MG Magnette KA, Magnette KD Instruction Manual

MISCELLANEOUS DRIVING HINTS

Do

read this Manual thoroughly and laid down.

Do

use the gears freely, particularly on hills and when accelerating after corners, in traffic, etc.

Do

free the engine by hand when cold before using the starter.

Do not

Do

Do please

Do

Do not

race the engine when of pistons and bearings, and may even result in piston seizure. same time do not allow warming up speed is 1000 r.p.m.

run the engine with the mixture control in the rich position longer than necessary.

avoid " harsh " driving, particularly when braking ; the smooth and powerful and need never be "stamped on."

drive slowly in the vicinity of the factory when visiting us.

retard the ignition before starting the engine.

write to us or come and see us (by appointment, please) when in any difficulty.

allow the engine to " pink."

slip the clutch except when actually starting off or changing gear ; change down in traffic, to bottom gear if necessary.

subject the tyres to glancing blows from the kerb when drawing up beside the pavement ; this may interfere with wheel alignment and have a serious effect on steering and tyre life.

it

carefully and follow out the instructions

is cold ; this will shorten considerably the life

it

to idle, this is equally injurious.

M.G.

brakes are

At the

The best

Do not

Do

lean on open doors.

under any circumstances allow the oil level to fall below half full best to keep

mix different brands of oil in the sump.

allow the engine to labour.

forget to top up the battery regularly.

forget to turn the petrol tap back to the main the tank.

leave the headlamps alight when the car is stationary at night ; this drains the battery unnecessarily and is very discourteous to other road users.

try to improve your car's performance by altering the ignition timing or interfering in any way with standard settings and adjustments. makers know best.

forget to lubricate clutch thrust.

always quote model, year, engine and chassis numbers when writing.

is

very important.

See Hints at the end of Pre-selector Gearbox section.

it

always up to three-quarters at least.

position after refilling

;

This

it

is

The

FOREWORD

The object of this lnstruction Book is to place the owner in possession of as much

detailed information as is possible concerning the

intended first of all in the early chapters to afford a pictorial survey of the chassis generally,

and the book is so arranged that all the essential information and instructions necessary

to mointain the car in efficient condition are contained in the early part. The remaining

chapters contain more detailed information which it is hoped will prove of interest to

most owners, including details of both the manual and pre-selector type gearboxes.

"

K

"

Type M.G. Magnette. It is

The time arises when

to the lnstruction Book can be of considerable value, as it points out both to the owner

and repair shops, unacquainted with the construction of the car, the correct method of

procedure.

There are a number of adjustments that have to be carried out from time to time

such as adjusting the valves and brakes, and more detailed information is given upon these

points separately. The book is provided with a comprehensive index, to which reference

should be made, as it is quite possible that either illustrations or reading matter con-

cerning the same parts may come under different headings. Should at any time the

owner fail to find the particular instruction he requires in the lnstruction Book, it is hoped

he will not hesitate to communicate with the Service Department at Abingdon, who will

always be only too ready to afford any assistonce they can at any time.

o

car has to be dismantled, and it is then that the reference

SECOND EDITION REVISED MARCH.

1934.

Page

One

IMPORTANT POINTS CONCERN1 NG LUBRICATION

The first thing that the owner will want to know concerning his car will be the various lubricants that are recommended by the makers and the points of the chassis that require attention. The engine oil filler is situated on the off-side of the engine, alongside which there is a dipstick. Under no circumstances should

the car be driven fast on the lower gears or exceeding

500

on top gear during the first

oil should be drained and the base chamber refilled with new oil. The oil filters

(one in the sump and the Tecalemit unit), which will be referred to later should be removed, the suction filter in the sump washed out with petrol, and the spare Tecalemit element should be fitted in place of the used one.

It is inadvisable to run a cold engine fast until the oil has had an opportunity of warming up sufficiently in order to circulate freely through the oil passage ways throughout the engine. The pump is called upon to suck from the base chamber or sump, oil which has become thick with standing, particularly in cold weather.

It

may be noticed that the oil gauge will show that the pressure may drop as the speed increases that the oil has not become sufficiently thin to pass into the pump in sufficient quantity. The gear type pump lubricates the whole of the engine including the valve gear.

The gcarbox and rear axle are provided with hexagon-shape filler caps. Indication of the height level to which oil should be filled is provided, preventing overfilling. It must be remembered that the car should not be moved in any way when the gearbox and back axle are filled, otherwise additional lubricant may be carried round by the teeth of the gears, thus causing the housings to contain more oil than they need and above the proper level.

if

the engine is driven at all fast when cold. This

miles. At the end of this period the engine

40

miles an hour

is

an indication

Chassis fittings are conveniently lubricated from six oil nipples, three on either

side of the car, which are to be found on the brackets supporting the dashboard. The bonnet has to be lifted and the nipples fed with gear oil hy means of the large

oilgun. Reference to the plates attached to the dashboard show that on the off-side

of the car there are nipples marked A, B and C, and on the near-side of the car nipples cables, the spring anchorages, the steering box and column and the brake cross shaft. The brake operating spindles which pass through the brake-drums require no lubrication. The steering head pins and the track rod and other steering ball socket joints need lubricating separately.

D,

E

and

F.

The points lubricated by these various riipples are the brake

Only

use Shell Gear Oil in the

large oilgun.

A two-colour lubricating chart is provided herewith indicating the lubrication

that is carried out from the central dashboard nipples and is shown in black, and

the other points on the chassis that have to be individually lubricated are shown with a red circle surrounding them, and if there is any doubt in any owner's mind as to the exact location of the nipples, they can be seen in one or more of the illustrations of the parts contained in this Manual. The only point that cannot be normally seen is the clutch thrust lubricator, but this will be dealt with on page

60,

from which

the thrust can be lubricated, which requires attention every 2000 miles minimum.

it

follows that the clutch inspection cover has to be removed before

Page

Three

The following lubricants are recommended by the Company

:

Approved Engine

Oils.-Every M.G. Magnette is tested on Duckham's Adcol "NP5" Aero and the sump and spare quart tin are filled with the same brand when the car is issued new. We very strongly recommend the use of this oil, both in Summer and Winter.

On the rare occasions when this oil cannot be obtained the following oils

are approved for use

:-

Duckham's Adcol " NP3 " Summer and Winter.

Wakefield Castrol

"

XL " Winter, " XXL " Summer.

Filtrate Sports Winter and Summer.

Mobiloil " AF " Winter, " D " Summer. Pratts' Essolube Racer Summer and Winter. Price's Motorine "C " de Luxe Summer and Winter.

Shell Triple or Aero Shell Summer and Winter. Speedolene Aero Engine Oil Summer and Winter.

"

WW

"

Sternol

Heavy Summer and Winter.

Under no circumstances are a mineral and vegetable base oil to be

mixed in the engine.

Gearbox and Back Axle.-As

in the case of engine oils, we recommend the

use of Duckham's oil, the particular brand for the gearbox and back axle being:-

Pre-selector Gearbox.

Duckham's Adcol

"

NP3."

Filtrate S.C." Wakefield's Castrol F."

Manual Gearbox and Back Axle.

Duckham's Gear Oil

N."

Pratts' Super Gear Oil. Castrol Swanshot Gear Oil. Price's Motorine Amber " B." Filtrate Gear Oil. Shell Gear Oil. Mobiloil " C " (Gearbox " CW

").

Speedolene

"

H."

Hub Grease. Duckham's Adcol HBB."

Universal Joints.

Great care should be exercised in mixing oils at all, and

Duckham's Hardy Spicer Grease.

it

is far preferable, if anybody wishes to run on a particular oil or is so forced by circumstances, that the old oil should be drained out first and a complete replenishment made.

Under no circumstances should paraffin be used to wash out the lubricating system unless the engine is being dismantled. lubricating system of the engine will be found on pages

More detailed instructions of the

48

and 51, which deal with the complete travel of the oil from the sump to the pump, thence through the various pipes and passages in the engine to the main and big-end bearings and to the overhead valve gear. The oil pump is provided with a relief valve of very simple construction consisting of a spring and dash-pot enclosed in a cover plug. The details of this will also be found on page 50.

We will now leave the general

lubrication summary with the advice to

only recommended oils whenever obtainable.

Keep the receptacle that is used

use

for filling clean and covered, and also wash round back axle and gearbox filler caps before these are unscrewed.

The gearbox and back axle should be refilled

for preference after the car has been running some time, so that the

lubricant has had a chance to become fluid.

Page

Four

THE M.G. MAGNETTE

CHASSIS DETAILS

General Survey.

As soon as the owner receives his car

it

is advisable to make himself familiar with its general mechanical details, and in order to assist in this as much as possible,

it

has been thought advisable to take a general pictorial survey of the chassis, in particular those parts that cannot be seen after the body has been fitted.

The view shown in Illustration No.

it

people, but

is the view obtained by looking at a chassis from underneath.

I

is perhaps a little unconventional to some

The petrol tank is not in position, but the undershield beneath the gearbox and front passenger's compartment can be seen. Certain views taken from below will be

described later, more particularly the front and rear axles.

ELECTRIC

WIRES

Illustration I.-View of the M.G. Magnette chassis as seen from below. As the position of batteries differs on models, these must be considered as of one type only. It is possible to see from this illustration the position of the slide to obtain access through the undershield which is fitted only with manual type gearboxes to drain the gearbox. The suspension can be examined and the manner in which the wiring is carried out in flexible metal tubing.

It

will be noticed that the undershield is fitted with a slide, which should be pushed forward in order to obtain access to the gearbox drain plug, which can be removed by using a box spanner.

The body is mounted on extension brackets attached to the outside of the frame, these extension brackets can be seen in the illustration.

In order to obtain a better view of the chassis,

It

will also be seen that semi-elliptic springs are fitted fore and aft.

it

has been found desirable to

remove unnecessary fittings such as wings, wheels, etc.

Page

Five

Illustration

in the frame, showing the position of the dynamo and water pump, the manner in which the frame is upswept over the axle and details of the suspension. Note the position of the oil filter. The insert

shows the thermostat for controlling the temperature of the water.

2.-Near-side front view of the engine mounted

Illustrations Nos. 2 and 3 are two separate views of the near-side of the engine.

No.

2

particularly shows the upsweep of the frame over the front axle, the mounting of the radiator and the two water connections to the engine. Cooling is by water pump, which is driven direct from the timing gears. The water pump is shown in the illustration coupled to the radiator by means of a rubber hose.

On certain models an

adjustable thermostat is fitted to control the water

temperature.

It will be seen from this illustration that the dynamo, which is placed vertically and driven from the front end of the engine, has a coupling at its upper extremity which in turn operates the overhead camshaft.

This illustration indicates the position of the oil relief valve, which is situated

on cop of the oil pump, and the relationship of the latter to the Tecalemit oil filter.

A

rubber buffer is placed between the frame and the front axle, and the position where the brake cable passes through the frame will be seen, as well as the oil pipes which lubricate the spring anchorage.

Page

Six

One small pipe in front of the engine should be noted.

This is the oil delivery pipe from the pump to the overhead valve gear. This particular unit will be dealt with separately.

3

Illustration No.

shows another view of the near-side of the engine and chassis and the manner in which the exhaust manifold and water outlet pipe are bolted to the cylinder block. It will be seen that the exhaust manifold is formed into two branches which unite at a point underneath the undershield which is in

front of the silencer, as can be seen by referring to Illustration No. I.

Illustration

position of the self-starter operated through the solenoid. The central-

ised position of the oiling nipples will be seen on the dashboard bracket from which pipes convey lubricant, as shown on the oiling diagram. The electrical wires are enclosed and the cut-out and fusebox covers

have been removed to disclose these fittings on the dashboard.

The Tecalemit oil filter can be seen and the tap has been replaced

by a plug on later models.

).-Rear view of the near-side of the engine, showing

The self-starter is situated on this side of the engine, being attached to the

flywheel housing, the action of the self-starter being controlled by a solenoid.

A

number of details of the electrical equipment can be seen, including position of

the cut-out and fuses, the wires from which are carried in a covered casing.

Page

Seven

We will now pass to Illustration No. engine, as shown when fitted in the frame. towards the rear end of the engine, and just in front of this a dipstick is provided in order to test the level of the oil in the engine from time to time. Whenever the dipstick is removed, first of all wipe be taken after removal. The oil gauge on the dashboard which indicates the engine oil pressure is coupled up to a tap situated close to the oil dipstick, as shown in the illustration, which makes necessity arise.

it

possible to cut off the oil from the gauge, should

4,

which is a view of the off-side of the

The oil filler, as will be seen, is situated

it

clean, insert, and a correct reading can

Illustration 4.-General off-side view of the engine and chassis before the body is mounted.

The central lubrication nipples and pipes are clearly shown, as well as the petrol feed pipe to the

change-over tap; the bottom bowl of the Petrolift acts as a filter. It will be noted that the carburetters

are set slightly at an angle, giving access to the sparking plugs.

The lubrication details can also be studied, viz. the position of the engine oil filler and dipstick.

At the top left of the illustration, the Petrolift will be noticed, which is electric-

ally operated. The lubrication of the spring anchorages and certain other parts are

carried out from the centrally located oil nipples A, bracket. These will be seen on referring to the oiling chart, those on the near-side being marked

There

nipples, which are referred to in the oiling chart as A, correct lubrication and part which each nipple supplies. The pipes can be seen in the illustration attached to the side member of the frame. The radiator and dash-

board are tied together by means of stay rods which are adjustable.

This illustration also shows the magneto and the three carburetters in position.

The carburetters are supplied with petrol from the Petrolift, which is provided

with a filter which consists of a metal bowl at the base of the Petrolift. The

removal of the filter

pipes will be seen on the left-hand bottom corner of the illustration

situated just behind the body bracket to permit of their removal from time to time.

(Later models are fitted with a petrol pump, details of which are to be found at the end of this manual.)

Page Eight

D,

E

and

F.

is

a description upon the plate on the dashboard bracket, carrying three

is

effected by unscrewing the bottom nut. The petrol feed

B

and C attached to the dashboard

B

and

C,

indicating the

;

unions are

Momentary reference should be made to the jet control levers of the three

carburetters.

If

ever jets are adjusted,

it

is necessary to remove the pins in the

jet control rods, so as to give effect to the adjustments, but this matter will be

referred to later.

lllustration No.

5

is a close-up view of the off-side of the front of the engine and contains a number of points with which the owner should familiarise himself. There is first of all an oil level dipstick, which has already been referred to, the next

;

important point is the water drain tap which empties the radiator

this tap is actually beneath the radiator and is only indicated in the illustration to draw attention to

it.

In addition to this drain tap,

is another tap towards the rear of the cylinder block.

it

will be seen on lllustration No.

It

is necessary when draining

31

that there

the water to turn on both the taps, so as to be sure of draining the cylinder block

as well. Remove radiator cap while draining and leave

it

off

till

the radiator is

refilled.

lllustration

of the engine. The water drain tap is placed below the radiator (also shown

in lllustration No. 14). The position of the magneto drive through vernier

coupling can be studied. from the interior of the magneto to the contact breaker and cover. Never attempt to start the engine with the contact cover off. The jet control to the carburetter can be seen, and if ever it is necessary to adjust the jets, to remove the pins from the levers and adjust the equaliser rod.

5.-A

more detailed view of the components of the off-side

It

will be noted that there is an external wire coupling

it

is necessary

The magneto is mounted on a bracket and driven through a train of gears by

means of coupling with vernier adjustment, so that if ever the magneto is removed,

it

can be replaced without altering the timing gears.

It

is fitted with two points for lubrication (this should be carried out sparingly and with special oil), the oiling holes being covered by spring-loaded caps.

Special attention is drawn in the illustration to a wire which passes to the rear contact breaker cover. This wire is attached to the same terminal as the earth or switch wire, and

it

is

impossible

to start the engine

if

ever the contact breaker

cover is left off.

Page

Nine

No mention has so far been made of the lubrication details of the engine, except

the fact that oil is delivered from the pump to the overhead valves operating

mechanism. It stands to reason, of course, that oil which is so delivered will have

to be returned to the sump, and this is effected by means of two external pipes,

one of which is shown in Illustration No.

5.

The oil return conducts oil in the

magneto timing gearcase, so that this is virtually automatically lubricated.

Illustration

ing (pre-selector model); the details of all the various levers can be studied and the location of the stop light switch.

6.-Central view of the chassis, showing the gearbox mount-

The next point in Illustration No. 5 is the steering gearbox, which is attached to a bracket on the front cross member of the frame. It will be seen that the steering box is lubricated from the central lubricating nipple

The next illustration, No.

6,

deals particularly with the view of the dashboard,

C.

steering column, clutch, brake, and accelerator pedals, gearbox and the general

controls of the car, including ignition control. The ignition and jet controls are

operated by two small levers situated alongside the change speed lever. The hand

brake lever is on the near-side of the gearbox.

The actual illustration is of a chassis fitted with pre-selected gearbox, and the

gear control lever will be seen at the end of the remote control tunnel. owner should realise that the petrol tap

is

brought close to him, whereby the

The

control of the main and reserve petrol feeds can be switched over while the car

is in motion by simply turning the knob on the right-hand side of the tunnel. The slow-running control is

marked.

The stoplight switch controlling the stoplight to the rear of the car

placed on the opposite side. Both controls are clearly

is

coupled direct to the foot brake-rod.

Page Ten

The speedometer is driven from the rear of the gearbox immediately in front

of the universal joint.

The latter is coupled to the front end of the propeller shaft

by means of a splined telescopic joint, allowing for the rise and fall of the rear axle

and the movement of the rear springs.

Continuing the general survey of the portion of the chassis which is entirely covered by the body, reference should be made to lllustration No. illustration, No.

8,

has been prepared to cover the lubrication points more clearly,

7.

A

separate

as well as the petrol feed line in the off-side of the frame.

lllustration No.

7

shows the gearbox attached in the frame by means of a tubular cross member which passes through the bell housing which unites the engine to the gearbox.

It

also shows the change speed lever and the remote control.

In order to prevent any fumes from the engine entering the driving compart-

ment of the car, the flywheel housing is fitted with a rubber ring which seals the

it

space between

and the metal covered dashboard. In both types of gearbox

employed in this chassis, the filler orifice is situated on the near-side.

The adjustment for taking up wear of the hand brake is effected by means of

a thumb screw adjuster situated at the base of the hand brake lever, clockwise

rotation being applied to tighten the brake. Extension body brackets are mounted on the frame as shown. The electric wires from the battery are carried in a metal conduit situated underneath the frame on the near-side. The propeller shaft is normally entirely covered by a shaft tunnel, the forward mounting of which is shown

7.

in lllustration No.

small

oilgun is introduced to lubricate the front universal joint.

This shaft tunnel has a hole drilled in

it

through which the

lllustration

gearbox and pre-selector gear control. overflow plug must be unscrewed so as not to overfill the gearbox. chassis can be seen, viz. body mounting bracket, electrical wire conduits, the hand brake adjuster

and the bracket to which the shaft tunnel is mounted.

7.-View of the near-side with the central portion of the chassis showing the The filler plug should be noted, and when this is used the

Various other details of the

Page Eleven

Gearbox extension with remote gear control showing reverse catch and speedometer

connection.

General view of manual gearbox mounted in the frame, showing oil filler and grouped

controls.

Page Twelve

Illustration

pipes and unions and the manner in which the electric wires are carried out in a conduit to the instrument board. and that they require lubrication occasionally through holes suitably provided.

8.-Off-side view of the

It

should be realised that universal joints are enclosed beneath the shaft tunnel,

M.G.

Magnette chassis, showing position of petrol feed

Illustration

when these are fitted forward of the axle in two 6-volt units. The tubular propeller shaft has purposely been disconnected from the axle to indicate the flange fitting; access to

the batteries and rear axle filler and dipstick can easily be obtained under the rear seat.

9.-View of the rear end of the chassis, showing location of the batteries

Page

Thirteen

A

separate illustration, No.

8,

has been prepared to cover the lubrication points

more clearly, as well as the petrol feed line in the off-side of the frame.

It

will be seen in this illustration that the clutch pedal is directly coupled to a lever on the gearbox by means of a rod, which in the case of pre-selected boxes does not actually operate a clutch as in the ordinary accepted sense of the term.

it

The effect, however, is the same, as

disengages the transmission of power from

the engine to the rear axle.

The rear cross member has extensions on either side in which the rear end

of the rear springs are located, as seen in lllustration No.

9.

The petrol tank is, in point of fact, actually supported in the body. The two petrol feed pipes couple up the main and reserve supplies.

Illustration

end of the frame showing suspension and shock

absorber mounting.

10.-General view of the rear

lllustration No. 9 is a view of the rear end of the frame as seen after the body

has been removed.

shows the propeller shaft uncoupled from the rear axle

;

It

the position of the batteries will be noticed and the fact that two 6-volt units are employed, coupled in series to make a 12-volt unit.

Care should be exercised to see that the nuts which hold the battery lids in position are secure, after the batteries have been filled up with distilled water on regular occasions. The fact that the battery is temporarily out of sight sometimes leads to its neglect. Removal of the rear seat pan will afford access to the batteries and to the rear axle filler, which is combined with a level dipstick to show exactly how much oil the axle actually contains.

10

lllustration No.

the chassis.

Particular instructions will be given subsequently of points fhat can

is the opposite view of the rear axle seen from the rear of

be seen in this illustration, including the shock absorbers, rear brakes, and spring anchorage lubrication.

Page Fourteen

lllustration No.

particularly one side of the rear axle.

I I

is a close-up view of the rear end of the chassis, showing

It

will be noticed that there is a rubber-

lined rebound clip which limits the travel of the rear axle upwards when passing over very bad roads, and there is a rubber buffer on the frame as well to cushion any shock in the opposite direction. It will be seen that the shock absorbers are

mounted on a stabilising cross member, the tension of the shock absorbers being obtained by tightening the central nut in a clockwise direction.

The brake cable passes to the anchorage underneath the axle, and the manner

In

which the rear brakes are applied can clearly be seen.

Illustration No. 12 is a view well worth studying, as

it

shows that the springs are attached to the rear axle and the manner in which the lubrication pipes convey oil to the points of suspension from the central dashboard nipples.

On previous illustrations the batteries are situated in front of the axle.

In

some models they are situated behind the axle in the manner shown.

Illustration I l.-Close-up view of the rear axle showing detachable cover-plate.

The shock absorbers are mounted on the cross member and the rebound of the axle

is limited by the clip.

On later models the greaser is not provided for the rear brake camshaft.

Page Fifteen

Illustration

part of the rear spring mounting. smaller bolts preventing the leaves from separating. will also be noted, as well as the petrol pipe unions at the rear end of the line. Rear axle drain plug should be noted.

12.-View of the chassis as seen from below. The springs are attached by means of four large bolts, the two

The brake cable attachments to the rear brakes

The shock absorber bracket forms

Steering.

out of view,

As the majority of the parts of the steering layout are normally

it

is as well that the owner should become familiar with the design and

principle, so as to be able to carry out his part of lubrication, and in the event of any accidental damage occurring to see exactly how the parts are mounted. The steering box proper is attached to a bracket on a cross member of the frame and

is fitted with a drop arm which is coupled to a transverse pull and push rod. This will be seen in subsequent illustrations, but the view shown in Illustration No.

13

is of the steering bracket and the off-side steering arm, which is in turn coupled to the steering head and the track rod. Every articulating joint of the steering is

fitted with an oil nipple. The track rod is threaded at either end. In fact, all the

steering rods, or, to be more exact, tubes, are threaded.

This permits of accurate

adjustment and to take care of any irregularities in the tracking of the wheels.

It is essential that anyone removing one of the divided track rods should see

that

it

is replaced the correct way round.

On examining the track rod

it

will be found that the ball joint at one end of

the rod is loaded by a coil spring, and at the other end by a coil spring washer.

The end with the double coil spring washer should be fitted to the triple

steering arm.

The end with the coil spring should be fitted to the steering knuckle arms.

The draglink from the steering gear to the triple steering arm is fitted as standard with the long ball end at the steering gear, and the short ball end at the triple steering arm. This could be reversed without doing any harm, but as there

is no object in reversing

it,

the standard position should be adhered to.

All steering connections should be lubricated with gear oil.

Page

Sixteen

Illustration 13.-Front end view of the frame after the engine has been removed : the brake cables pass through the chassis as shown. The front cross member is utilised tosupport the engine and the steering bracket is indicated: the oiling nipples on the steering rods should be examined.

Illustration 14.-View of the front end of the chassis as seen from below. The spring mounting

will be noted, including rebound spring clips. General steering lay-out can be examined, including the pivot lever which passes through the axle body. of the radiator drain tap and the bolts on the underneath side of the sump to secure crankcase.

Particular note should be made of the position

it

to the

Page Seventeen

Steering on the

M.G.

Magnette differs from conventional layout. It will be

noticed that in Illustrations 13 and 14 a pivot is formed on the off-side on the front axle between the spring perches to accommodate the main steering arm. This special shaped arm is connected to the drop arm of the steering by means of a

short coupling tube, and its lateral movements in one direction or the other cause the pivot lever to operate the track rods which are attached to

is

socket joints. Each of the articulating joints

provided with a lubricating nipple

it

by means of ball

which requires attention, from time to time ; in fact, reference to the oil chart shows that they should receive lubrication by the oilgun every 1000 miles.

lllustration IS.-View of the near-side front end of the chassis, showing the steering head and shock absorber, and sub-divided track rod with the lubricator nipples. be seen how the brake cable passes through the frame, terminating in a rubber-covered end. The greaser on the brake camshaft is not used on later models, and the shock absorbers are parallel with the chassis instead of transverse.

It

will

lllustration No. 13 also affords an excellent opportunity of seeing how the

brake cables pass from inside the frame through a bracket attached to the outside

of the frame, and lubrication of these points ensures the inner brake cables being

continually lubricated.

lllustration No. 14 is a view taken from beneath the front of the car. While

it

is primarily intended to show the underneath side of the steering box, the pull

push rod, track rod, and steering arms, yet at the same time

and

it

affords an excellent opportunity to examine the underneath side of the engine, timing case, oil pump, extension bracket which supports the radiator, and the attachment of the front axle to the spring by means of four bolts at each side, in addition to the

two bolts which prevent the leaves from separating.

Particular care should be taken to note the position of the radiator

drain tap.

lllustration No. 15 is a view of the front axle and near-side front wheel and steering head. The position of the pivot pin can easily be discerned as well as the lubricators on the pivot pin arm. The actual attachment of the shock absorbers

;

varies in different models, but the principle employed is the same

in most cases

Page Eighteen

they are attached to the wing bracket supports.

The passage of the brake cable through the frame will be noted and also the rubber-covered end of the brake cable.

The brake actuation lever is attached to the operating camshaft. Always be careful to make sure when lubricating the steering head that the lubricant exudes from the thrust races, as, in addition to lubricating the steering head pins, foreign

matter, as well as water, will be expelled.

lllustration

and the manner in which the cross shaft is supported at one end on a needle bearing.

Brakes.

in the book, and

illustrations

16.-Views of the brake cross shaft, showing the hand and foot brake adjustments.

No useful purpose will be served by including redundant illustrations

it

will already have become apparent from the examination of

Nos. 12 and 15 that the brakes are applied through the agency of steel cables which pass through covered outer cables from either side of the centre of the chassis to the brake-drums, the final application being shown in lllustration No. 15.

sketch is provided on page 22 showing

diagrammatically

how the brakes are

A

applied. A cross shaft is placed in the middle of the chassis, anchored at either end, and supported in the centre to a tubular cross member of the frame. This can be seen by referring to lllustration No.

7,

which more particularly illustrates the hand

brake. The lever is situated on the near-side of the gearbox, and towards the base

an extension will be found on which there is a thumb nut. The foot brake adjustment

is on the off-side of the car. The brake cross shaft removed from the car is shown in lllustration No. 16.

The foot brake pedal is coupled to the brake actuating cross shaft by a rod, and

either extremity of the brake cross shaft is provided with a pulley having holes

drilled through

it

top and bottom to receive the end adaptors of the brake cables. As either brake is applied, the brake cross shaft is rotated, pulling the rear brake cables forward and the front brake cables backward.

Page

Nineteen

Illustration

the thumb nuts should be turned in a clockwise direction.

17.-Details of the foot and hand brake major adjustments.

To tighten the brakes

Independent Adjustment.

Should

it

be necessary to adjust the brakes independently this can be done by means of adjusting screws fitted to the cable stops on the back plates. At this point on the cables a rubber dirt excluder is fitted in the form of a rubber tube, and this tube is mounted on what is actually the lock nut for this adjustment.

By undoing this lock nut the cable stop can be adjusted on its thread by the

amount required and the lock nut re-tightened.

The whole of the brake cross shaft is lubricated from one of the dashboard

nipples, and in order to give perfect freedom for the rotation of the cross shaft,

it

is mounted at one end on what is termed a needle or roller bearing. These are

it

shown in Illustration No. 16. Should cross shaft,

if

care is exercised the entire bush of the needle bearings need not be

ever become necessary to remove the

removed. To reassemble the needle bearing, the inner shaft should be covered with

grease and the rollers embedded in

it,

when

it

will be found that they will stop in

position in order that they can be inserted inside the cable operating pulley.

Page

Twenty

OUTER

INDIVIDUAL

CABLE

ATTACHMENT

ADJUSTING

/

CHASSIS

BRAKE

NUT

Illustration

17a.

-

-{

5.

$

c

RUBBER

TO

EXCLUDE

COVERING

pendent brake adiustment for each wheel, see text on page

Inde-

20.

The front and rear brake-drums of the car are identical in design. from time to time to remove the brake-drums in order to clean out the brakes or have them re-lined. The procedure is very simple. as shown in lllustration No. releasing the brake, the drum can be withdrawn by a slight tapping on the ribs with a wooden mallet or a piece of wood and a hammer. The brake-drum and its components are shown in lllustration No. 18, and in the right-hand side of the illustration the brake-shoes with the pull-off spring can be seen.

The countersunk screw in the fluted portion of the front hub is intended to permit the split pin of the hub nut being easily removed and replaced through the hole in the hub, when the complete hub

18,

take off the nuts with a

is

to be removed.

When the wheel is removed

in. spanner, and after

It

is necessary

NOT

-0

0

a

-

lllustration 18.-View of front hub after the brake-drum has been

removed, showing the type of brake employed.

A

SHIM

Page

Twenty-one

Brake Anti-squeak Device.

The brake-shoes are fitted with an anti-squeak

device, which consists of lead alloy blocks fitted into the channel section of the

brake-shoes and held in position by means of clevis pins and little coil springs. When vibrations take place in the brake-drum, they are communicated to the brake- shoes and the shoes vibrate

the lead weights, however, are in effect " left behind

"

;

by the vibrating shoes and energy is wasted in friction between the weights and the shoes.

The conditions under which the weights are mounted can in practice be made such that they can always waste more energy than the squeaking forces can generate and the squeak is prevented.

These are fully illustrated below.

Illustration 19.-Sectional view through a

brake-shoe, showing the lead weight attached to the brake-shoe, and the various component parts for same.

Showing diagrammatically how the brakes are applied.

Running Adjustments.

Before dealing with the detailed description and dismantling of the various units of the chassis, the owner may require to know particulars of adjustments which he can effect.

Illustration 20.-View

adjusting the valve clearance.

by single camshaft. By utilis

should never be undertaken

Tappet Adjustment.

of an M.G. Magnette engine, showing the operator in the act of

The removal of cover discloses the fact that the valve gear is operated

;ing an eccentric bush the valve clearance can be accurately set

unless the engine is hot.

:

this

Before the owner has had an opportunity of reading through the whole manual he may require to adjust his valves, and in order that he should know what is taking place, a careful examination of Illustration No.

20

will make the matter clear. He will probably be aware that there is a necessity

to have a definite clearance between the cam and the valve rocker

is

parts are distinctly marked in the illustration. It

of course important to see

;

the various

that the valve is properly seating when any adjustment is attempted, and this can easily be seen by the position of the cam in relation to the rocker. There is a single camshaft operating both the inlet and the exhaust valves. These are easily distinguished from the fact that all the exhaust valves are on the near-side of the engine and the inlet valves on the of-side of the engine. The valve rockers are attached to separate shafts at their outer extremity, and are provided with eccentric bushes. The opposite extremity of the rocker is wedge shaped, so that

if

the nut which forms parts of the eccentric bush is rotated, the wedge end of the rocker will either advance or recede from beneath the cam, and present a thicker or

thinner section to the face of the cam when this rotates. The rocker is locked in

20

position on the eccentric by means of a locking screw, and in Illustration No.

a

spanner is shown in position ready to slack off the locking set screw. The eccentric

bush can then be rotated inside the rocker boss to give the required clearance. See

that the bush does not rotate while the locking screw is being tightened.

Page Twenty-three

Correct clearance between the valve rocker and the face of the cylindrical

portion of the cam should be

illustration 2Oa.-Sectioned view of the cylinder head showing the correct position of the rocker eccentric, and the point at which the rocker clearance should be checked.

.006

in. when the engine is hot.

It

may be found that after grinding in valves the power will drop off unless

A

the length of the valve stem is also adjusted. for this purpose, consisting of a horse-shoe shaped piece of metal which, when

resting on the cylinder head, gauges the exact length of the valve stem that protrudes

through the guide. Such a tool is only necessary in the case of extreme accuracy

being required, and should only be carried out by an

adjustment being capable of taking care of normal needs. It may, however, be

necessary after the valves have been ground-in several times.

THE CORRECT VALVE ROCKER CLEARANCE IS

special gauge has to be employed

M.G.

Service Depot, the ordinary

.006

in.

FOR BOTH

INLET AND EXHAUST.

Page

Twenty-four

INSTRUCTIONS

FOR TWO-CARBURETTER MODELS

MAGNETTE

(See Sectional

Carburetter.-Separate instruction concerning the S.U. is provided with the car, but the following particulars specifically apply in the case of the M.G. Magnette.

To afford a richer mixture for slow-running, the jet control nut should be

unscrewed.

By screwing the jet adjusting nut upwards, the petrol consumption can be cut down if the owner is satisfied with a lesser degree of acceleration and speed, and sometimes in hot weather general all-round better carburation can be obtained

by thus cutting down the petrol supply. Screwing up too much may cause popping

through too weak a mixture.

A

little machine oil should be injected into the dashpot or suction chamber

brass cover screw every thousand miles, to lubricate the piston guide rod

drops of machine oil is advised for this purpose.

Under no circumstances should the body of the piston be lubricated.

illustration

on Page Twenty-five)

;

three

By inserting the finger through the air inlet to the carburetter, the piston can

be lifted inside the body of the carburetter, and should rise and fall freely.

Page

xxv

The use of the strangler, or, as

it

is correctly called, the jet control, is intended

only for starting when the engine is cold, and should be employed as little as possible.

The effect of using the jet control is to enrich the mixture when starting. If

it

is left in operation longer than is necessary the cylinder walls will be bathed with surplus petrol, which will soon have a damaging effect on the pistons and other parts of the engine as well.

Reference to Illustration No. 21 shows the jet control lever in position. The

jet adjustment nut is in point of fact only a stop against which the jet head rests

when the jet control lever

pulled backwards, so that

it

stands to reason that if

is

any adjustment of the jet has to be effected, this has to be carried out on each

separate carburetter.

It

follows that as all the three jet control levers are coupled

up, and if only one jet nut is unscrewed, unless the jet controls are slackened off

first,

all the other carburetters will have been adjusted similarly to any individual

one.

The two screws that hold the piston body in which the piston and suction disc operate should be removed, so that the piston and its guide rod can be cleaned. Extreme care should be exercised in removing the pistons, so as not to damage

the taper jet needle in any way. Mark the suction chamber before removal and

it

replace

the same way as originally fitted. Do not change the suction chambers

from one carburetter to another.

Sources of Trouble.-There are only four troubles which may affect the

functioning of the

S.U.

carburetters.

I.

The piston may be sticking and not functioning properly.

2. There may be dirt or water in the carburetter.

3.

The float mechanism may have become deranged, and the carburetter is

in consequence flooding.

The carburetters may require synchronising.

4.

Piston Sticking.-The suction piston consists of the piston proper forming

the choke ; the suction disc, into which is inserted the hardened and ground

;

piston rod working in a bearing in the suction chamber

and a tapered needle

regulating the jet opening. If the piston is sticking this can easily be ascertained

by inserting a finger in the air intake and raising the piston. The piston should

it

is

come up quite freely and return to its seat with a click as soon as

A

large percentage of the carburetters returned to the Works for correction

released.

have had the jet removed and replaced without being correctly centred. On no

account should the jet be tampered with.

It

is quite an easy matter to bend the needle if the piston is at any time removed,

it

in which case the needle is bent-providing the jet is not out of centre-remove

will bind on the jet and cause the piston to stick. To ascertain if

it

from the piston,

refit the suction chamber on to the body of the carburetter and see if the piston

it

falls freely. If the needle is bent the only satisfactory remedy is to replace

by a

new one.

Page

xxvi

Float-chamber Flooding. This is usually obvious from the quantity of petrol

flowing over the float-chamber and dripping from the air inlet.

Flooding is generally

caused by foreign matter finding its way on to the seating of the float-chamber needle.

It

can sometimes be removed by flooding the carburetter with the tickler pin, thus

permitting the incoming petrol stream to wash away the particles of grit, otherwise

access to the needle

it

the needle

in position.

is

After taking away the guide the needle will drop straight out ; the

is

obtained by removing the float-chamber top. To take out

necessary first of all to take out the pin which holds the needle guide

seating should on no account be ground in.

Copper packing washer

-

Copper packing washer

Jet holding screw

Brass washer

An enlarged section of the jet assembly. the junction between the jet and the jet bearing is rendered perfectly petrol- tight by means of two cork washers which are forced against the sides of the jet by a coil spring and conical washers. If the jet is dismantled great care must

be taken not to lose these washers.

-

Top half jet bearing

Cork gland washer

Brass washer

Bottom half jet bearing

Cork washer

Cork gland washer

Jet adjusting nut

It

will be noticed that

Synchronisation of Carburetters.-Before attempting to adjust the car-

buretters,

it

is

advisable to check over the following items.

Ignition timing.

clutch inspection opening. No. I piston

Set the I and 6 mark on the flywheel in the centre of the

is

then at T.D.C. Distributor and plug

points should be checked for cleanliness and gap, i.e. .015 in.l.020 in. on distributor and .018 in. on plugs, also valve clearance should be .006 in. between base of cam and rocker.

Having checked these items, remove the dashpot covers and the dashpots from

the carburetters, disconnect the jet coupling rod and screw the jet adjusting nuts

right up. On pushing the jets up to the full weak position the correct petrol level should be

mm. below the top of the jet. If this

is

not so, and assuming the floats

I

are in good condition and not punctured, the level can be adjusted by bending slightly

Page

is

xxvii

the guide controlling the float needle, up to raise or down to lower, whichever

required.

Next proceed to set the needle in the dashpots.

In the case of the

or piston.

Refit the dashpot and cover to the carburetters, making sure that, when

screwed down tight, the dashpots will fall on to their seatings with a click.

"

L

"

needle, the shoulder should be flush with the dashpot

Screw down the jet adjusting nuts two complete turns and screw off slow-running rod and butterfly adjusting screws so that they are not in use. Then slacken one butterfly flexible coupling bolt, press both butterflies hard closed and re-tighten

bolt, making sure neither butterfly moves during this operation.

Screw down the butterfly adlusting screws to allow engine to run at three

hundred to four hundred r.p.m. with ignition fully retarded.

It has been observed that the suction type screen wiper valve screw is usually left open by car owners, the wiper action being only controlled by the start and stop lever. The screen wiper valve screw should therefore be left open when adjusting the carburetters, as there is occasionally a slight leak at this point.

Allow engine to warm up to normal running temperature before attempting

to do the final adjustments. When that is attained the mixture may be judged

by the exhaust note.

one of the jet adjusting nuts up, making sure that the jet

If

the engine is hunting, which is due to rich mixture, screw

is

pushed up also.

If this makes no improvement, return

same process with the other. On the other hand, if the exhaust note

it

to its original position and try the

is

irregular the mixture is too weak and the jet adjusting nuts should be screwed down, first one and then the other.

Having obtained somewhere near the correct mixture a check can be made by opening the throttle suddenly, when both carburetters should spit back a light spray of petrol. (For maximum performance

it

is

advisable to set the adjusting

nuts one flat on the rich side of the setting.)

A fairly good check can be obtained for the synchronisation of the butterflies by opening the throttle by hand and noting the height of the pistons one with the other through the mouths of the carburetters while the engine is running.

General.-It will be realised from the foregoing that the S.U. carburetter is

a very simple instrument and easily managed when understood.

hand, considerable damage can be done if

it

is not treated correctly.

On the other

We would emphasise that the four troubles previously outlined are the only

ones that can be caused by defects in the carburetter, and

if these points are in order

the carburetter should on no account be dismantled or altered, since the trouble

must lie elsewhere.

Page

xxviii

lNSTRUCTJONS FOR THREE-CARBURETTER MODELS

Carburetter.

Separate instruction concerning the

S.U.

is provided with

the car, but the following particulars specifically apply in the case of the M.G.

Magnette. In normal use the needle numbers are-D6 either end, carburetter, with dashpot

DETACHING

NU7

TICKLER

PIN-

HEFDLE SEAT

&

N377B.

07

in the centre

NEEDLE-

FLOAT

-

Illustration 21.-Sectional view through an needle is locked into a piston which is causcd to rise by the suction increase the orifice of the jet, thereby governing the petrol flow. illustration that the effect of screwing the jet adjusting nut up or down has actually no effect on

the jet itself; two screws holding the suction disc outer chamber in position should be removed from time to time, and the suction disc and piston carefully cleaned with a dry rag should oil be used on the suction disc. The oil cap on the top of the suction disc chamber simply

lubricates the spindle which guides the suction disc during its up and down travel.

The steel adjusting screw on the outside of the carburetter is only intended for slow-running

adjustment and does not alter the mixture.

it

is simply an abutment for the jet head which is controlled by the jet lever. The

S.U.

carburetter, showing how the taper

of

the engine and so

It

will be realised by this

;

under no circumstances

Page

Twenty-five

To afford a richer mixture for slow-running, the jet adjusting nut should be

unscrewed.

By screwing the jet adjusting nut upwards, the petrol consumption can be cut down if the owner is satisfied with a lesser degree of acceleration and speed, and sometimes in hot weather general all-round better carburation can be obtained by thus cutting down the petrol supply. Screwing up too much may cause popping through too weak a mixture.

A

little machine oil should be injected into the dash-pot or suction chamber

brass cover screw every thousand miles, to lubricate the piston guide rod

;

three

drops of machine oil is advised for this purpose.

Under no circumstances should the body of the suction

disc or piston be

lubricated.

By inserting the finger through the air inlet to the carburetter, the piston

can be lifted inside the body of the carburetter, and should rise and fall freely.

it

The use of the strangler, or, as

is correctly called, the jet control, is intended

only for starting when the engine is cold, and should be employed as little as possible.

The effect of using the jet control is to enrich the mixture when starting. If

it

is left in operation longer than is necessary the cylinder walls will be bathed with surplus petrol, which will soon have a damaging effect on the pistons and other parts of the engine as well.

5

Reference to Illustration No.

shows the jet control lever in position.

The jet adjusting nut is in point of fact only a stop against which the jet head rests when the jet control lever is pulled backwards, so that

it

stands to reason that if any adjustment of the jet has to be effected, this has to be carried out on each separate carburetter. It follows that as all the three jet control levers are coupled up, and if only one jet nut is unscrewed, unless the jet controls are slackened off

first, all the other carburetters will have been adjusted similarly to any individual one.

The two screws that hold the piston body in which the piston and suction disc operate should be removed, so that the piston and its guide rod can be cleaned. Extreme care should be exercised in removing the pistons, so as not to damage

the taper jet needle in any way. Mark the suction chamber before removal and

it

replace

the same way as originally fitted. Do not change the suction chambers

from one carburetter to another.

Page

Twenty-six

NEVER

USE

CLEAN

Illustration 2la.-View of the inlet manifold with the carburetters attached. The right-hand carburetter is partially dismantled, showing the suction disc removed from the suction chamber and the relative position of the jet and needle. To lubricate the spindle engine oil should never

be used ; only very light machine oil.

The two accompanying illustrations, Nos. 21a and 21b, show the actual

carburetter arrangements on the M.G. Magnette. It is seldom that the float-

it

chamber requires dismantling, but

is very simply effected by removing the

nut on the top of the float-chamber and removal of the petrol pipe union.

The jet control arrangements are shown in Illustration No. 21 b.

SUCTION

CHAMBER

L

PIS

NEEDLE

lllustration 2lb.-Another view of the carburetters, showing one of them partially dismantled. The principal feature of this illustration is the adjustment of the jet control lever.

3

can be screwed up or down, but which couples up the jet control levers must be uncoupled and the rods shortened or lengthened so that the control levers force the jet heads up against the abutments

if

FLOAT

CHAMBER

COVER

any modification is made to any individual carburetter, the rod

ADJUSTMENTS

1,

2

and

The nuts

3.

1,

2

and

The three jet adjusting nuts are marked

levers force the jet head up against the nuts

If

normal running. control lever is not altered to correspond, the Nos. I and same extent as No. be to enrich all the three carburetters instead of, say, No.

remove the pins from the front and rear carburetters and alter the position of the yoke ends, so that the pins which couple them to the jet control levers pass through freely.

it

much experience.

which have already been dealt with, and the clutch (when fitted), which will be dealt with under its own heading, but the following notes will indicate the nature of the adjustments which are carried out with the aid of a spanner and screwdriver.

It

is possible with three carburetters to effect changes in adjustment, and

is a matter that should not be lightly undertaken

Other points that may require adjustment from time to time are the brakes,

nut No.

3,

and the effect of the adjustment,

3,

for example,

1,

2

and

3,

and when the jet control

1,

2

and

3,

the carburetters are set for

is

screwed downwards, and the jet

2

jets will only rise to the

if

so carried out, will only

3

only.

It

is necessary to

if

the operator has not had

Page

Twenty-eight

COIL IGNITION INSTRUCTIONS

The high-tension distributor with automatic advance mechanism is very accessible. It is provided with an oiler to lubricate the spindle, and only a few drops of thin machine oil should be put in every 1000 miles.

lllustration

A.-The

distributor and

oil

pump.

The contacts can be inspected by unclipping the two springs, when the cover

it

carrying the high-tension leads can be removed. Should for any reason

be necessary to check or adjust, the ignition timing should be set so that No. I piston is on top dead centre, measured on the flywheel when the

centre of the clutch inspection aperture and the inlet valve of No.

1

6

marking is in the

6

is opening and the contact breaker arm pointing towards No. I plug segment. Then, after slackening the -securing bolt, rotate the body of the distributor and set the contact breaker arm so that the fibre heel on the contact breaker arm is on the apex of the cam on the rotor. The points may require adjustment from time to

time, and a spanner is provided with the tool kit for this purpose. The clearance

between the points should be

15-20/1000 of an inch. They are carefully set

before leaving the Works. It is not advisable to alter the setting unless the gap

varies considerably from the gauge supplied. If adjustment is necessary, proceed

Page

xxix

as follows :-When the contacts are fully opened, slacken the locking nut on

the stationary contact screw, and rotate

set to the thickness of the gauge. After making the adjustment, care must be taken to tighten the locking nut.

The centre spindle of the high-tension distributor carries a " Bakelite " arm

called the " rotor."

(it

simply pulls off)

exercised to see that

mention lost after secured by means of pointed contact screws which pierce the rubber insulation to make good contact with the cable strands, at the same time securing the cables tightly in the terminals. The screw heads are located on the inside of the distributor

moulding.

The automatic advance device, which consists of a centrifugal governor, is

housed in the distributor body. and needs no attention beyond very occasional lubrication. the distributor moulding by pushing aside its two securing springs. electrodes are clean and free from deposit. with a dry duster and clean the electrodes with a cloth moistened with petrol. Clean the outside of the moulding, particularly the spaces between the terminals. Next examine the contact breaker kept free from any grease or oil. cleaned with very fine emery cloth and afterwards with a cloth moistened with

petrol. Care must be taken that all particles of dirt and metal dust are wiped away.

Misfiring may be caused

I.

Dirty sparking plug (correct plug gap 20/1000 inch).

2.

Cracked porcelain.

3. Bad connection to high-tension leads.

4. Bad connection from high-tension distributor to coil.

5.

Improper adjustment of make-and-break points.

6.

Dirt between make-and-break points.

7.

Defective coil.

It can only

it

affords an excellent thiefproof device, but care should be

it

does not become chipped or in any way damaged, not to

it

has been removed. The ends of the high-tension cables are

if

the contacts are not kept clean, or by any of the following

fit

It

it

by

its

hexagon head until the gap is

on the spindle one way.

is

packed with grease before leaving the Works

If necessary, wipe out the distributor

;

it

is important that the contacts " C " are

If they are burned or blackened, they must be

If

this part is removed

Occasionally remove

See that the

:-

These causes exclusively deal with the electrical side.

remote cause of electrical failure, namely bad earth contacts from the battery to

the frame. Other causes of misfiring can be attributed to carburetter and improper

valve adjustment, the latter having been already dealt with on pages 23-24.

Page

xxx

There is one other

Very little attention is needed to keep the distributor in first class condition.

We advise that

it

is inspected occasionally, and the following instructions on

lubrication, cleaning and adjustment should be carried out.

Illustration

Contact Breaker.

A-Distributor moulding. B-Securing springs for moulding. C-Contacts.

D-Lock nut. F-Rotating cam.

G-Condenser.

H-Rotating distributor arm.

J-Spring contact.

B.-Distributor

and

Distributor.-Occasionally remove the distributor moulding by pushing aside

its two securing springs.

See that the electrodes are clean and free from deposit. If necessary, wipe out the distributor with a dry duster and clean the electrodes with a cloth moistened with petrol. See that the carbon brush is clean. the outside of the moulding, particularly the spaces between the terminals. examine the contact breaker

;

it

is important that the contacts " C " are kept

Clean

must be taken that all particles of dirt and metal dust are wiped away. Misfiring may be caused if the contacts are not kept clean.

The contact breaker gap is carefully set before leaving the Works, and a gauge is provided on the spanner dispatched with each distributor. Provided that the cam is kept clean and that the instructions on cam lubrication are carried out, the contact breaker gap will only need adjustment at very long intervals. It is not

advisable to alter the setting unless the gap varies considerably from the gauge. If adjustment is necessary, proceed as follows :-When the contacts are fully opened, slacken the locking nut

D " on the stationary contact screw, and rotate

it

by its

"

hexagon head until the gap is set to the thickness of the gauge. After making the

adjustment, care must be taken to tighten the locking nut.

Lubrication-(l) Distributor Shaft. Add one or two drops of thin machine

oil through the oiler provided about every 1000 miles.

Cam. About every 3000 miles, give the cam the slightest smear of vaseline.

(2)

(3)

Automatic

rotating arm

"

Timing

H

"

(Illustration No.

Control. About every 3000 miles withdraw the

B)

from the top of the spindle by lifting

it

off, and add a few drops of thin machine oil. Do not remove the screw exposed to view, as there is a clearance between the screw and the inner face of the spindle through which the oil passes to lubricate the automatic timing control.

Page

xxxi

Coil.-The coil unit is not adjustable in any way, and requires no attention

beyond seeing that the terminal connections are kept tight, and the moulded coil

top is kept clean.

Warning Lamp.-A warning lamp is provided in the instrument panel, which

gives a red light when the ignition is

"

ON

"

and the car is stationary.

The warning lamp will also light when the engine is running very slowly, due to the fact that the dynamo is not running at sufficient speed to generate a high enough voltage to actuate the cut-out.

The Detection and Remedy of Ignition Faults.-If a failure of ignition or misfiring occurs, unless the cause is at once apparent the owner is strongly recom- mended to proceed in accordance with the following routine, which should quickly enable him to locate the trouble.

Before proceeding with the examination, make sure that the trouble is not

due to defects in the engine, carburetter, petrol supply, sparking plugs, etc.

Engine

the ammeter reading. The engine should be turned by hand if

will

not Fire.-Switch on the ignition, turn the engine and observe

it

is known that

the battery is in a low state of charge.

If an ammeter reading is given which rises and falls with the closing and opening

of the contacts, then the low-tension wiring is in order.

If the reading does not fluctuate in this way, a short in the low-tension wiring is indicated, or the contacts are remaining closed. When no reading is given, a broken or loose connection in the low-tension wiring is indicated, or the battery may be exhausted.

Examine the high-tension cables, i.e. cables from the coil to the distributor, and from the distributor to the plugs. If the rubber shows signs of deterioration or cracking, the cable should be renewed. Remove the distributor moulding and examine the contacts

;

if necessary, clean them as described on page xxxi.

Turn

the engine over by hand, and see that the contacts come together.

If a fault is indicated in the low-tension wiring, examine the cables from the switch or junction box to coil, and from coil to distributor.

See that the battery terminals are tight and that the cables from the switchbox to the battery are secure. The battery may be dismissed as the cause of the trouble if the lamps will light.

Test the coil independently of the distributor as follows :-Remove the cable

it

from the centre distributor terminal, and hold

about $ in. from some metal part of the chassis and turn the engine. The sparking should be strong and regular if the coil is functioning correctly.

Misfiring and Bad Starting.-Examine the high-tension cables and the plugs.

20

If necessary, adjust the gaps to the correct setting (about

thousandths of an inch).

Sooty or oiled plugs may be dismantled and washed out with petrol.

The plugs and high-tension cables may be tested by removing the plugs in turn and allowing them to rest on the cylinder head and observing whether a spark occurs at the points when the engine is turned by hand. It should, however, be noted that this is only a rough test, since the plug

is

under compression.

it

is possible that a spark may not take place when

Remove the distributor moulding and see that the electrodes and contacts are

clean. If necessary, clean them as described on page xxxi.

See that the contact gap

setting is correct.

If after carrying out the examination suggested, the trouble cannot be found, we advise that the equipment should be examined by the nearest Lucas/Rotax Service Depot, the addresses of which are given later.

Page

xxxii

FOR

CARS

WITH

MAGNETO

IGNITION

Ignition.

is provided on the magneto itself.

Little instruction need be given on this subject, as a special handbook

The principal points for the owner to note are the gap clearance of the contact breaker points, and the fact that they should be clean and the rocker-arm free on its bush. Only a very occasional lubrication is required, and a high-quality machine oil introduced into the oiling apertures, two or three

drops at a time.

The magneto is attached by means of set screws fitted to the base, which register

with holes in the plate, and is also secured by means of a strap, which can be seen

by referring to Illustration No.

5.

"

K1 " TOURER

AND

"

K2

"

OR

"

K3" MODELS

Valve timing diagram for the K.1 Tourer and K.1 Saloon.

materially and must not be confused.

It

will be seen that these vary

Page Twenty-nine

General description of the M.G. Magnette Engine.

In order that the

owner may become familiar with all the details of the power unit, illustrations have

been prepared showing the complete engine unit removed from the chassis.

OIL

FILLER

lllustration

engine bearer member. The sump drain plug can be seen, as well as the position of the dipstick.

lllustration No.

22.-Three-quarter view of the engine removed from the frame, showing front

22

is a view of the off-side of the engine suitably lettered to

indicate the various parts. More detailed instruction will be subsequently given

concerning the items of magneto and dynamo. The principal points of interest

in this illustration are the location of the oil filler and the sump. The majority

of the details shown in this illustration have already been covered in lllustration

No.

5,

but this particular illustration shows the sump or oil container of the engine

its

and special tool

drain plug, which consists of a brass nut having a square plug hole.

is

provided in the tool kit for removing this drain plug.

seen in this illustration that there

It

is

a return oil feed pipe from the front and

A

will be

rear end of the cylinder head.

The near-side of the engine, Illustration No.

23,

shows a good deal more than

can be seen when the engine is in the chassis.

Page

Thirty

There is a front extension on the extreme left of the illustration which acts for the dual purpose of starting handle bracket and radiator support as well as front engine bearer.

The water inlet pipe from the pump to the cylinder block is also visible.

It

will have become obvious that the front end of the crankshaft is fitted with

gearing which in turn drives the oil pump. The oil is sucked up by the pump from

it

the sump and delivered to the oil filter, where

passes through a specially prepared

inner body, to be delivered to the main bearings and the overhead valve, camshaft

and rockers. The manner in which the oil

is

delivered to the two centre and rear

main bearings will be seen subsequently, as well as the details of the oil filters.

The filter is fitted with a cover-plate, the removal of which gives access to

the felt element that has to be changed and cleaned periodically.

ENGINE

BEARER

Illustration

shows the water inlet and outlet pipes and the two exhaust branches of the oil pump and the fact that oil is drawn from the sump and delivered by the pump to the oil filter, whence

pipe as shown, the extension of which feeds the overhead valve rocker gear.

23.-Near-side view of the engine removed from the frame.

it

is delivered internally to three main bearings. The front main bearing is fed by the

;

it

further shows the position

This first of

Page

all

Thirty-one

lllustration No.

24

is a front view of the engine, showing in more detail

the position of the oil and water pumps.

Illustration

showing the dynamo in position between the crankshaft gears and overhead valve mechanism the latter will be noted, and the surplus lubricant is conveyed back to the sump through the large pipe which feeds the magneto drive. The position of the oil and water pumps can be seen.

24.-A

view of the front of the engine

;

the oil feed pipe to

It will be noticed that the dynamo is placed vertically in front of the engine and the armature shaft is utilised to drive the overhead valve gears. The magneto drive gear is seen on the left-hand side of the illustration and the return oil pipe

feed which conveys part of the surplus oil back to the magneto drive, at the same

is

time being of sufficient diameter to effect a release for crankcase fumes and

point of fact what

is

shown on the off-side of the engine which serves to feed the overhead valve gears with oil. This whenever the head

is

commonly known as a " breather pipe." An oil feed pipe

is

attached to the cylinder head and should always be removed

is

lifted, very carefully, because behind the nut and flange there

in

is a detachable metering or restriction pin, which controls the amount of oil that

passes through the orifice.

If ever the pin is removed, as can be seen on referring to lllustration No.

it

will be noted that

it

has a flat machined on

it

which meters the amount of oil

33,

passing to the valve gear.

Page

Thirty-two

Illustration No.

25

shows the water and exhaust ports after the manifolds have

been removed and the copper and asbestos washers which are fitted between them

and the cylinder head. If ever the manifolds are removed, the washers should be

inspected and cleaned, as well as threads on the studs by which the manifolds are

refitted. The nuts holding the manifolds to the studs should be gradually tightened so as to get a uniform pressure and prevent any possible chance of leakage through distortion.

25

Illustration No.

also shows the valve operating parts after the cover has

been removed.

The valve cover

is

held in position by six nuts which should be tightened up

evenly so that a good joint between the cover and the cork washer fitted on top

is

of the cylinder head

formed. It will be noticed that the two bosses on the top

of the valve cover are slotted, so as to form breathers.

Illustration

This is held in position by six nuts, and these should be tightened equally to make the cover

evenly on the cork washer. The slots in the valve cover can be seen acting as crankcase breathers.

It

is possible to see how the exhaust pipes and water outlet pipe are attached to the engine and the

type of washers employed.

25.-View of the overhead valve mechanism as seen after removal of the cover.

Page Thirty-three

tit

Action of the Electric Starter.

The engagement consists of a coarse threaded shaft on which a pinion is fitted. When the starter button is pressed the starter motor rotates quickly, causing the pinion to be rotated, but owing to

it

the form of this pinion

has a tendency to travel along the starter extension shaft, and thus engage with the teeth of the flywheel, the shock being taken up by a recoil spring.

The moment the engine starts up and the self-starter button is released the flywheel rotation causes the pinion to travel back along the starter shaft out of engagement.

The front end of the self-starter shaft is provided with a square end, and

it

is

possible in the case of only a slight jam to rotate this spindle with a spanner and

thus disengage the starter pinion from the flywheel. The above explanation will

26,

be made clearer on examining lllustration No.

from the engine.

It

is held in position by two studs and one bolt, and there is a

which shows the starter removed

distance plate between the starter housing and the flywheel housing. The flywheel teeth can be seen and also the spiral thread on the extension of the starter shaft, along which the engaging pinion travels to and fro

;

the recoil or buffer spring is

clearly visible.

DISTANCE

AND

STARTER

PIEC

BOLTS FOR

MOUNTIN

BOL

lllustration

The forward end of the self-starter spindle has a squared end on to which a spanner can be fitted,

in the case of a slight jam of a pinion in the flywheel. The squared end should be turned

clockwise, i.e. in the same direction as the engine.

Before dealing with the internal dismantling of the engine,

26.-Self-starter removed from the engine to show the method of attachment.

it

may be as

well to clean up the exterior fittings by referring to the method in which the engine

is mounted in the frame at the front end, and the removal of the self-starter.

The self-starter has already been illustrated in lllustration No.

No.

26

shows the starter after removal of the engine.

A

solenoid is fitted on the top of the self-starter

3,

and lllustration

Should, through accident, the solenoid stick and the starter continue to revolve,

it

is possible to pull the smallest of the wires on the solenoid off, which will break

the electrical circuit. This might also be necessary in the event of the self-starter

switch jamming.

Engine Mounting.

tube passes through the bell housing of the flywheel and

It

has been seen in lllustration No. 7 that a steel

is

supported in two brackets, one on either side, in order to secure the rear end of the engine unit in the frame. The front end mounting, however,

is

entirely different.

The frame is provided with a front tubular cross member, which is shown in

A

lllustration No.

27,

in its relationship to the engine.

central bracket is attached

to the cross member, and by means of a bridge piece the front end of the engine

extension bracket is attached to the cross member, bushes being interposed to afford a certain amount of resiliency to the mounting, and isolate the engine from

road shocks. Reference back to lllustration No. 14 shows the front cross member in the frame, and the means whereby the radiator is attached thereto. This illustration is particularly instructive in case

it

is necessary at any time to remove the radiator. The radiator proper is mounted on the front engine extension by means of two studs and nuts and interposed fibre washers.

lllustration 27.--The frame front cross member has been photographed in its relation to the front engine bearer. and attaches

The top cover of the water pump has been removed to expose the pump impeller.

it will be noted that there is a bearer clamp which holds the engine in position

it

to the cross member, bushes being employed as shown.

Page Thirty-five

Engine Dismantlement.

having been dealt with,

it

The principal external components of the engine

is now proposed to describe (in dismantling the engine

pictorially) the construction of the engine and the method employed.

The first feature in dismantling is obviously the cylinder head. This

comprises the timing of the valves, the dismantling of the valve gear, the grinding

of the valves, the relationship of the cylinder head to the cylinder block, and the

method of driving the camshaft.

The first thing that should be borne in mind is that considerable care has been exercised in the design of the engine to render the operation of valve timing as simple as possible. through the dynamo

is in a certain position there

It

must be taken for granted that the drive from the crankshaft

is

correct, and

it

follows, therefore, that when the dynamo

is

a definite relationship between the arms of the

coupling on the top of the dynamo and the position of the piston in the cylinder.

The firing order is

1,

4,

2,

6,

3,

5.

Illustration

be carefully studied because has to do with the timing of

the valves and shows the relative

position of the armof thedynamo

coupling when two of the pistons

are on top dead centre. The

valve cover cork washer can be

seen and the type of gears em-

ployed to drive the camshaft.

28.-This should

it

When the cross head of the dynamo coupling is in the position shown

in Illustration No. 28, that

attached to the dynamo towards the front of the car, then No.

is

on top dead centre.

is

to say with the bolt through the coupling

I

piston

The cross head coupling attached to the dynamo is connected to the coupling

driving the vertical spindle by means of laminated steel discs, and when the overhead

valve camshaft cover is removed bevel gear wheel which meshes with the camshaft gear wheel, and

it

will be seen that there is a mark on the driving

if

ever the camshaft is removed, provided nothing else has been disturbed, these marks only have to coincide for the timing to be correct.

Page

Thirty-six

It

also follows that if one wants to find top dead centre to check the ignition,

or for any other purpose,

it

can be found by turning the dynamo coupling, as shown

in the above illustration.

it

To check which cylinder is on the firing stroke,

is necessary to remove

the valve cover and inspect the position of the camshaft.

The form of coupling employed

permits the cylinder head being removed

without disturbing the timing in any way.

It

is

only necessary to undo two bolts to disengage the coupling between the

dynamo and the cylinder head.

Diagram showing the order in which the cylinder head nuts

should be screwed down on M.G. Magnette engines.

Illustration

view of the inlet side of the engine ; the pipe on the left-hand side of the illustration

feed from the head to the base chamber.

that a tool like a screwdriver can be inserted to help to lift the cylinder head.

Cylinder Head Removal.

it

is

obvious that the oil delivery pipe and return pipes will have to be disconnected. There are 18 cylinder head holding-down bolts, and Illustration No. cylinder head partially removed. the cylinder head and the cylinder block, and if ordinary care

29.-View of the cylinder head partially removed from the cylinders.

It

will be noted that there are notches in the gasket, so

Whenever the cylinder head has to be removed

29

A

copper and asbestos gasket is fitted between

is

employed, there

is no reason why this should be damaged in removal.

Page Thirty-seven

This is

is

a return

shows the

a

EXHAUST

COMBUSTlON

Illustration 30.-Interior of cylinder head, showing the position of the valves, the shape of the combustion spaces and the holes through the cylinder head through which the holding-down studs pass, as well as the passage ways conveying water to the head. The coupling for the overhead camshaft will also be seen.

CHAMBERS

SIDE

SHOWING

VALVES

DRIVE

COUPL'NC

ALWAYS

GASKET

NOTE SLOT

Illustration 31.-Plan view of the cylinder block and the gasket. gasket should only be fitted the correct way. An important feature of this illustration is the cylinder head water drain tap which has to be open when the entire water system is to be emptied, as, for example, in Winter time as a precaution against frost.

REPLACE

CORRECTLY

NOTCH

It

should be noted that the

Page Thirty-eight

After the cylinder head has been removed the combustion chamber side

presents the view seen in lllustration No. 30.

Each valve is numbered in relation to the number on the face of the cylinder head, and valve grinding can be effected either by holding the valve in a suitable clamp from above, or by means of the screw-

It

driver from the combustion chamber side.

is as well to study this illustration from another point, namely the possible necessity of changing a valve spring. In a case of emergency a rod can be inserted through the sparking plug hole, after the sparking plug has been removed, which will prevent a valve dropping into the cylinder, but should a spring break to change the spring.

As has been previously stated, there are 18 cylinder head

it

is preferable to remove the head in order

studs, and lllustration No. 30 shows the holes through which the studs pass. The

remaining holes in the head are for the free travel of water from the cylinder body through the gasket to the cylinder head. The right-hand side illustration shows the coupling attached to the pinion shaft which operates the overhead gears.

lllustration

32.-Plan view of the cylinder head, showing the camshaft and rockers in position.

A plan view of the cylinder block after the head has been removed, lllustration No. 31, is worthy of careful consideration. position and the cylinder head gasket resting alongside.

to replace a gasket,

it

should be carefully noted that there is only one way in which

It shows the cylinder head studs in

Before an attempt is made

the gasket must be fitted. There is in the first place a slot at one end, while there are holes at the other end for the passage of water, and the shape of the gasket must conform to the contour of the combustion chamber. This illustration affords an opportunity of noticing notches made in the gasket which afford a method of inserting a screwdriver or similar tool between the head and the cylinder block, in order to

break the joint, which may have become very tight

due to the presence of carbon

and jointing compound.

Page Thirty-nine

FRONT

BEARING

Illustration

its four bearings, which are white-metal lined. restriction or metering pin will be noticed. This pin has a flat machined upon amount of oil that passes to the overhead valve gear. Oil is delivered to the front bearing of the camshaft and then through the rocker-shafts to lubricate the rockers and remaining bearings.

33.-A very detailed view of the cylinder head, showing camshaft removed from On the left lower side of the illustration the

it

to control the

Illustration

drive removed. A separate unit has been dismantled, the parts being as follows

A number of shims are employed in the original assembly. These should never be dismantled.

I.

Camshaft driving shaft.

2.

Camshaft driving bevel pinion.

3.

Camshaft driving bevel pinion key.

4.

Hyatt roller bearing.

4a. Hyatt roller bearing,

5.

Bevel pinion bearing sleeve. Oil drain housing (front).

6.

Universal joint fork for bevel

Page

Forty

34.-View of the underneath side of the cylinder head, with complete camshaft

7.

Bevel pinion washer.

8.

Bevel pinion thrust washer.

9.

Bearing retainer plate.

10.

Bevel pinion oil thrower.

Part not numbered

in ion.

:-

Illustrations Nos.

32

and

33

need very little explanation as they afford to those interested a detailed view of the cylinder head as seen from above, with the valves in position. In the latter illustration the camshaft is removed and the articu-

lating rockers and the rocker-shafts can be inspected.

The camshaft is held in position in four white metal bearings by bearing caps, and oil is introduced into the bearings along each of the rocker-shafts, as well as supplying the drilled rockers. The surplus oil, as has been previously explained,

drains back into the sump. It will be noticed that some of the cylinder head holding-

down bolts pass through brackets that support the rocker-shafts in position and

a

&"

size spanner

By swinging the valve rockers out of position

is

required to slacken the holding-down bolts.

it

is possible to remove the

valve cups and cotters after the camshaft has been lifted. Particular note should

be made of the thrust on the front end of the camshaft, and be sure that this registers properly when the latter is reinstated.

The number of washers will be seen on the camshaft, consisting of a steel disc

and a spring steel washer. These fit on the front side of the front bearing next to

the bevelled gear, and take the thrust of the drive of the shaft.

Before leaving the cylinder head the details of the overhead valve gear drive

can be seen by reference to Illustration No.

34.

The complete camshaft drive assembly on the left-hand side of the illustration is bolted to the cylinder head by four studs and nuts, and in order to ensure correct meshing of the driving pinion with the camshaft gear wheel a number of shims are employed between the face of the cylinder head extension and the assembly housing. These are in point of fact a Factory fitting, but care should be exercised, if ever a unit is removed, to see that the shims are neither damaged nor omitted. The caption beneath the illus- tration suffices to describe

it.

Page

Forty-one

Engine Components.

The following operations will deal with a number

of parts, such as oil pump, magneto and bracket, and dismantling of timing gears.

prior to dealing with the most important subject of engine knowledge, namely lubrication. All the various parts are so CO-related in the case of the M.G. Magnette

it

engine that the description may appear to be somewhat disjointed, but

will be found that the illustrations will materially assist and are, in fact, more informative than any amount of text.

Take Illustration No.

35.

This shows a view of the engine as seen from below.

There is the sump, the oil pump, the front engine bracket, the dynamo, magneto

drive, and suction filter.

Illustration

position of the suction filter inside the engine, also how the magneto bracket is bolted to the base chamber. by the timing gear off the same shaft that drives the magneto gears.

REMOVING AND CLEANING THE SUCTION

35.-This illustration is primarily intended to show the

It

will be noted that the oil pump is driven

FILTER

The suction filter consists of a tube surrounded by a fine mesh gauze through

which the oil in the sump has to pass prior to being drawn into the oil pump.

The filter should be removed from time to time and thoroughly washed in petrol. When replacing

is not damaged.

it,

make sure that the fibre washer between the nut and the sump

It

is also necessary to see that the short snail-shaped pipe between the suction filter and the oil pump is properly tightened up, because a very small leak at this point would be fatal to the oil circulation.

Page

Forty-two

THRUST

OIL

PUMP

REC~STER~INSIDE

MAC DRIVE EXTENSION

SPINDLE

RELIEF VALVE

SPINDLE

NGAGES WITH

GEAR

CRANKSHAFT

ON

Illustration

removed from the engine. driven by the same shaft. inside the extension of the magneto drive.

36.-Magneto drive and oil pump It will be seen that these are

The oil pump spindle registers

METHOD OF DRIVING AND DISMANTLING THE OIL PUMP AND

MAGNETO DRIVE (IF FITTED)

Reference to the above illustration shows the pump actually removed.

pump is attached by means of five studs.

The upper end of the pump spindle castellated and registers inside the lower extension of the magneto drive, which shown in Illustration

NO.

36

coupled to the pump, thus forming a single unit and

The

is

driven by the gear which engages with the gear on the crankshaft.

In order to remove the magneto drive,

bolts which secure

it

to the timing cover, disconnect the magneto and give the

housing a half turn in order to disengage the gears, as

are a true worm. If ever the magneto drive

it

is

first of all necessary to undo the

it

will be noticed that they

is

removed,

it

is necessary to remove the oil pump first, and when the oil pump is replaced care should be exercised to see that the splines register without force.

Page

Forty-three

MAGNETO

DRIVE

NOSE REAR

PIECE

HALF

CRANKSHAFT

Illustration

love the fan pulley,

rerr

I

i"

B.S.F.

tWC

bolts, the pulley can be withdrawn from the crankshaft.

37.-Oil pump, water pump and magneto drive removed from the engine.

it

is necessary first of all to unscrew the starting handle dog nut and, by us

To

ing

Illustration No. 37 shows how the front end engine bearer has first of all been

a

removed from the front end engine cover.

B.S.F.

bolts, which act as drawers, and then the front end engine housing can be

The pulley is removed by using

in.

withdrawn by the removal of four bolts, disclosing the front end of the crankshaft, as seen in lllustration No. 37.

The forward end thrust of the crankshaft is taken

through a hardened steel washer butting up against the white metal of the front

main bearing. The rearward thrust is taken by interposing steel and white metal

washers between the housing and the timing gear.

It

stands to reason that before the pulley can be removed the nut on the front end of the crankshaft which acts as a starting handle dog, and shown at the bottom of lllustration No. 37, must first of all be removed.

It should be highly improbable that the magneto drive need ever be dismantled,

It

it

is copiously lubricated and runs on ball bearings.

as

consists, as can be seen

in Illustration No. 38, of the housing in which there are a pair of spiral gears attached to the vertical and horizontal shafts.

Poge Forty-four

The lower extremity of the vertical shaft is fitted with worm gear, and there

is a thrust washer placed between the vertical gear and the shaft housing.

38,

magneto coupling is shown on the right of Illustration No.

consisting of a star

The

coupling, which is bolted on to the magneto shaft and registers inside a flexible body of the other half of the coupling, which is attached to the magneto drive spindle. The magneto can be removed simply by slipping the two couplings out of engage-

ment, after undoing the strap and set screws, but whenever this is done

it

is as well to mark how they come out so that they can be properly re-engaged in relation to the proper firing order.

It

is always possible to increase the amount of advance of the magneto by slackening the nut on the vernier coupling referred to, and rotating the latter slightly and then tightening the nut, but as

is set when

it

leaves the Works is best for

it

all-round running.

Illustration

component parts have been dismantled to show the manner in which the shafts are supported. The magneto coupling has attached to the magneto fits.

Details of the magneto drive, showing a complete drive on the left, and the

38.

a

moulded rubber inset into which the portion of the coupling

Page

Forty-five

lllustration

mesh the drive gears it will be noted that packing shims are interposed between the dynamo body

and the timing case. The water pump is driven by a separate gear in front of the bevel which drives

the dynamo.

40.-This shows the manner in which the dynamo is driven. In order to correctly

DYNAMO

given under the heading of the electrical section on page at some time to remove the dynamo.

DRIVE.

Full details of the method of removing the dynamo are

92.

It may be necessary

This is a comparatively simple matter if reference is made to lllustration No. 40. The front end extension of the crankshaft is fitted with two gears, a helical bevel and a worm. The helical bevel drives the

dynamo, and here again we find the necessity for correctly assembling gears, which

is taken care of by a number of interposed thin metal shims. The dynamo gear

is attached to the spindle by means of a bolt and tab washer, the gear being held

in position on the shaft by means of a key. The gears are suitably marked for re-meshing, but the dynamo cannot be put back wrong if No.

top dead centre and the coupling on the top of the dynamo placed on so that

points accurately fore and aft, as indicated in lllustration No.

Water

Pump.

lllustration No. 41 shows the complete water pump after

removal from the engine, and below this the pump will be seen dismantled.

I

28.

piston

is

put on

it

The

principal point of which the owner has to take care is the packing gland adjustment.

This consists of a brass bush screwed at one end to register inside the pump body and hold the gland, consisting of special pump packing, in position that will prevent water creeping along the pump spindle and leaking. The packing gland nut can

be tightened by inserting a small piece of rod in the holes drilled in the nut and using the side of the pump body as a fulcrum.

In order to remove the pump from the engine

two nuts that hold

it

in position, and after the removal of the rubber hose

connections it can be withdrawn by giving

it

a gentle pull. Care must be exercised,

it

is

necessary to unscrew the

however, in reinstating it to see that the gears mesh, before any pressure is put on the pump in replacing the impeller will rotate on the shaft.

it.

Should any foreign matter find its way into the pump

It is held in position by a small bolt. The slot in the shaft is larger than the diameter of the bolt to allow for endwise adjustment.

There are three small items which really only concern the Repair Shop. They relate to the removal of the gear wheels from the crankshaft and the front end housing of the base chamber. After the dynamo has been removed

it

is possible to withdraw the worm wheel from the crankshaft by tapping

it

with a suitably soft tool, such as a piece of brass, through the dynamo housing.

It is a parallel

fit

on the crankshaft and is held in position by a key.

WATER.

PUMP

BY

TAPER

AND

Illustration 41.-View of the water pump completely dismantled. The principal point of

interest to the user is the packing gland tightening nut. The gland needs no lubrication and should

only be tightened sufficiently to prevent leaks, should they occur.

SEE

SEPARATE SECTION DEALING WITH COIL IGNITION

KEY

AND DISTRIBUTOR.

lllustration No.

42

shows the necessity of employing a puller to remove the helical bevel pinion from the crankshaft. The holes in the pinion are tapped B.S.F.

3

in.

To remove the front end housing

4~

in.

in the form of two

B.S.F. bolts. These are shown in lllustration No.

We then see, in lllustration No.

it

is also necessary to use a means of withdrawal

48,

the front end of the crankshaft, also the

two keyways on the crankshaft on to which the two gear wheels

42.

fit.

TOOL

FOR

WITHDRAWING

GEAR

CR

AN

FROM

KSlJAFT

FRONTCOVER

lllustration

helical bevel wheel is

a

wheel removal tool, similar to that shown, in order to extract this. The principal parts are as

:-

follows

Engine

5

quarts of oil are contained in the sump when filled to its proper level.

The oil flow can be followed by referring to lllustration No.

42.-View of the components attached to the front end of the crankshaft.

a

tight

fit

on the shaft, held in position by a key, and

I.

Helical bevel wheel.

2.

Worm wheel for driving oil pump.

Lubrication.

5.-Packing shims.

The actual lubrication of the engine is very simple.

3.

Distance collar.

4.

Washer with thrust face.

it

is

43.

necessary to utilise

The

Here we see the sump, oil suction pipe, and the pump. Oil is delivered from the pump to the oil filter, which is shown attached to the near-side of the engine and having two connections

I

and

2.

The oil filter is also shown removed in this illustration, with

Poge Forty-eight

the connections I and 2 marked thereon.

seen on the removed oil filter marked

In point of fact the holes that can be

"

oil feed holes " couple up with holes drilled across the crankcase, so that the oil that is forced by the pump into the oil filter is cleansed and is delivered internally to the two centre and rear main bearings.

The oil feed passes through the union No.

2

to deliver oil by means of an external

pipe to the front main bearing and the overhead valve gear.

illustration

which is connected to the sump by the oil suction pipe, and the external view of the oil filter

which has unions marked

is delivered through two small holes which communicate with the main bearings of the engine, as well as the pipe to the pressure gauge on the dashboard.

The Tecalemit oil filter, referred to on this page, shown in complete form and also dismantled. The various figures serve to indicate the position of the various components to assist assembly when fitting a new element.

43.-View of the front part of the engine showing the position of the oil pump,

I

and

2.

After oil has passed through the element inside the filter

ALWAYS

L13

KEEP

TIGHT

it

Page Forty-nine

PUMP

BODY

PAPER

OIL

RELEASE

DIFFERENT

LENGTH

BOLTS

IDLER

GEAR

Illustration

pump spindle engages with the idler gear.

The principal part of the pump to examine is the relief valve, which consists of a plunger, spring and hollow cap nut. When and allows the plunger to uncover a passage which will cause the pressure of the pump to drop. There is no adjustment to the amountof pressure

by a spring.

The pump

44. The components of the oil pump, which is of the gear type.

theoil pressure registers a pre-determined limit, thespring is compressed

;

this is determined at the Factory, and isgoverned

is

of the gear type, fitted with a cover-plate and having a by-pass

CUP

The gear on the

relief valve incorporated in the body of the pump. The relief valve, as can be seen

44,

in Illustration No.

consists of a cover which encloses a spring and maintains the small piston up against a seating in the pump body until such time as either the force of the oil through pressure or non-fluidity in cold weather forces the piston off

its

seating. The release of excess oil will maintain the oil pressure at a point pre-

It

determined by the makers, dependent upon the resistance of the spring.

is obviously possible to increase the tension of the spring by introducing washers in the cap, or obtaining a stronger spring, but no such alterations should be effected without first obtaining the advice from the Works.

Page

Illustration

baffled to prevent surging. this is removed, be careful to see that washer at the front.

Fifty

45.-View of the interior of the sump, showing how

It

is fatal to get an air leak.

it

The suction filter is shown in position. If ever

it

is screwed up tightly against the fibre

is

Oil

that is forced to the main bearings finds its way under pressure to the big-

end bearings through holes drilled in the crankshaft, whence in the usual course

it

is thrown out by centrifugal force finding its way upwards to lubricate the pistons

and gudgeon pins. The path of the oil can better be followed

if

the dismantling of

the engine is now continued.

Before proceeding with the details of the oil circulation

the interior of the sump, from which

it

will be seen that there are a number of

it

is as well to examine

baffles to take care of oil surging, and also the manner in which the suction filter registers in a boss in the centre of the sump.

lllustration No. 46 shows a view of the crankshaft in position after the sump has been removed. The crankshaft runs in four main bearings, the front and rear bearings being white metal lined bushes and the two centre bearings being of white metal cast direct in the split steel housings. Examine for a moment the crankshaft

after removal.

Owing to the size of the balance webs of the crankshaft

it

is

necessary to employ split housings to accommodate the two centre main bearings

and to register these in the barrel type crankcase. These housings are held in

position by long bolts which pass through them, and a view of the crankshaft after

it

has been removed is shown in lllustration No. 47, which shows the crankshaft, front end housing with its bush for the front main bearing, the rear end housing of the crankcase and the split centre main bearings, and the manner in which the bolts pass through them.

lllustration

crankshaft in position in the main bearings. The oil feed pipe to the three main bearings can be seen and also the heads of the bolts crankcase in which the main bearing housings are fitted and lock these in position.

46.-View of the base chamber after the sump has been removed, showing the

1,

2, 3

and

4,

which pass through the centre supports of the

As has been stated already, the front main bearing is fed with oil by an external

pipe, and

it

is now possible on examining lllustration No. 46 to see how the oil feed holes on the side of the base chamber correspond with the large front cross web coupling up the two halves of the crankcase and, of course, integral therewith. The two centre and rear main bearings receive their supply from the oil pipe that can be seen in the illustration.

The crankshaft centre main bearings are fitted into housings which will be

shown later, and these housings are held in the crankcase by means of long bolts,

1,

2,

3

Nos.

and 4, the bolts being prevented from turning by the use of tab washers.

Page

Fifty-one

There

is

one other point that should be noted in this illustration, namely the

position of the oil feed to the main bearings. It has been shown in lllustration No. 46 that the centre and rear main bearings are fed by one pipe, which delivers oil to the main bearing housings and to a union below the rear main bearing. The oil then goes via the bearing feeds as marked

l,

2,

3

and 4 in lllustration No. 47.

The rear main bearing

is,

however, differently designed. An examination

of the rear end of the crankshaft, as shown in lllustration No. 48, will disclose the fact that the crankshaft has a tapered rear end, and

is

fitted with a key. A flange

is fitted on to this with an extension. The object of the flange is to act as a mounting

is

for the flywheel. A white metal lined bush

fitted over this extension and

registers inside the rear end of the flywheel housing.

CRANKSHAFT

HOLE

lllustration

end housing. end of the crankshaft is fitted with a sleeve to receive the flywheel. is white-metal lined.

47.-View of the crankshaft removed from the engine and its relation to the front

It

will be noted that the two centre main bearings are split in two halves. The rear

MAIN

B

EEARlNG

0

!.:r

S

SLEEVE

The front end main bearing

Before dealing with the rear main bearing and its construction,

it

may be as well to examine the crankshaft, two views of which are shown in lllustration No. 48, the main journals being indicated by the letter

indicated by numerals,

1,

2,

3,

4,

5,

6. A close examination of the illustration will

" M "

and the big-end journals

show that the shaft is drilled so that oil can pass through the holes in the shaft from the main to the big-end bearings. The front end of the crankshaft is slotted to receive two keys, on which the timing gears are fitted. The rear end of the

crankshaft, however, can be seen in two positions, I and

showing that on one side there is an oval slot with a hole in

2,

in lllustration No. 48,

it,

and on the other

side there is a key, the purpose of which will be made clear on examining lllustration

No. 49.

is

First of all the flywheel

No. 2 in lllustration No. 49. This flange has a hole in

attached to the crankshaft by utilising the flange

it

on one side and a keyway cut on the inside. The external extension of the flange fits inside the rear main bearing and

is

locked in position by a nut which can be seen on the end of the crankshaft in

is

secured to the tapered end of the crankshaft by means of a key, and

lllustration No. 48.

Page

Fifty-two

OIL

FEED

HOLE AND

rT

(51

Illustration 48.-Two views of the crankshaft: (I) the front end of the shaft two keyways on to which the timing gears arefitted: at the rear end can be noted the oil feed hole and slot. The lower illustration (2) shows four main bearings marked

key at the rear end to register the rear journal and flywheel flange on the shaft.

is

provided with

"M

"

and also the long

The hole in the flange 2 registers with the oil feed hole in the slot in the

crankshaft

3,

so that the

lubricant which is delivered to the union on the rear main bearing I passes through hole 2 and into the hollow crankshaft in order to lubricate the big-end bearings.

SPLIT

CENTRE

BEARINGS

MAIN

Illustration 49.-This is primarily intended to show the manner passes through the flywheel housing, the actual journal of the shaft being the sleeve 2. bearing

of the sleeve 2, which registers with the slot in the crankshaft shown in Illustration

I,

which is really upside down, receives oil through the nipple; this passes through the hole

,

OIL

HOLE

in

which the crankshaft

Page Fifty-three

The main

48.

3

In order to remove the crankshaft hub

to that shown on the right-hand side of Illustration No.

it

is

necessary to employ a tool similar

It

50.

has already been

shown that the flywheel, hub, and bearing sleeve are fitted on to the crankshaft by

means of a taper and key

is

normal clutch

employed, but the method of flywheel attachment is similar in

;

this type of flywheel actually illustrated

is

used when a

all cases.

Note

:-Should the owner have the misfortune to run a bearing-in other

words, through insufficient lubrication the bearings become molten-it will be found that part of the white metal will actually run into the oil channel ways in the crankshaft and block these. Cases have been known where the bearing has

been refitted, and omission to clear the crankshaft has only resulted in the bearing

running immediately after reassembly. that all the ducts through the crankshaft are cleaned out, and

If

ever a bearing runs,

it

is

necessary to see it

may even be

necessary to remove the blanking plugs and pass drills of correct size through

It

the holes.

run into the oil ways, and

it

is possible to see

may be found, however, that only a small quantity of white metal has

if

a syringe of thin oil is squirted through these oil ways

if

they are clear.

Illustration

bolted to the detachable rear crankshaft flange, which latter is held in position by the large hexagon

nut and split pin.

the right-hand side of the illustration.

Page

Fifty-four

50.-Rear view of the flywheel in position on the crankshaft.

It

is necessary to use a withdrawal tool to remove the flange ; this is shown on

The flywheel is

GUDGEON

FLOATING

DURALUMtN

END

IN

PISTON

CAPS

Illustration

float in piston and connecting rod. prevent scoring the cylinder walls.

Connecting Rods, Pistons and Gudgeon Pins.

the type of connecting rod employed. with three rings (the lower one being a scraper ring). to rotate in the piston boss and

51.-The gudgeon pin is hardened and ground and is free to

It

is fitted with duralumin end caps to

Illustration No. 51 shows

The pistons are of aluminium alloy fitted

The gudgeon pin is free

the small-end bearing of the connecting rod.

Duralumin end caps are pressed into the gudgeon pins so that these can contact

with the cylinder walls without in any way damaging them. White metal is cast

it

direct into the connecting rod for the big-end bearings, and

will be noticed that the bottom cap is of generous proportions and is held in position by means of two bolts. The heads of the big-end bearing bolts are so formed that they register with the connecting rod and are thus prevented from turning round.

Page

Fifty-five

Various types

I.

Cylinder head gasket.

2. Oil filter body joint.

3. Joint for oil pump.

4. Main oil feed flange joint.

5.

Cylinder head feed pipe joint.

6. Cylinder head drain pipe joint (top rear).

7. Water pump joint.

8. Joint for oil base.

9.

Joint for cylinder jacket cover-plate.

10. Exhaust flange gaskets.

I

I.

Carburetter flange gasket.

12. Cylinder head drain pipe joint (front

13. Ditto (front top).

14. Ditto (bottom rear).

Page

bottom).

Fifty-six

of washers used.

15. Joint for oil gauge adaptor.

16. Exhaust manifold joint (front).

17. Ditto (intermediate).

18. Ditto (rear).

19. Valve cover joint.

20. Joint for bell housing.

21. Joint for front bearing housing.

22. Joint for oil filler.

23. Joint for magneto bearing cap.

24. Joint for Tecalemit

25. Joint for magnero drive casing.

26. Induction manifold gasker.

27. Joint for oil pump cover.

28. Joint for water outlet pipe.

29. Joint for engine hose piece.

filrer cap.

FOR CARS FITTED

WITH

MANUAL TYPE GEARBOX

Clutch.

speaking fool-proof; that is to say, when the clutch pedal is pushed down the power

from the engine is disconnected, but when the pressure on the pedal is released the clutch engages. From a point of view of actual maintenance there are only two items in connection with the clutch that the owner need trouble about-

one is periodical lubrication of the clutch withdrawal ball race or thrust ; secondly,

adjustment of the set screws attached to the withdrawal arms in order to give the

necessary clearance between the clutch plates when the clutch is disengaged, and

equally to prevent slipping when engaged.

Access to the clutch withdrawal collar is obtained by removing the clutch

cover-plate.

none at all.

Always use non-separating grease. Do not put more work on the withdrawal

bearing than is necessary by pressing the foot on the clutch pedal when driving.

TO

do so will overheat the withdrawal and induce clutch slip.

Before proceeding with a description of the clutch, to study the details shown in lllustration No. seen when removed from the flywheel housing. In the first place there is a withdrawal shaft consisting of a finds a bearing in either side of the housing. This shaft is attached to the clutch

pedal, so that when the latter is pushed forward the force the clutch withdrawal sleeve forward into contact with the friction-faced disc which is attached to the three withdrawal arms, which has the effect of separating the clutch plates and compressing the springs which cause the centre plates to be gripped between the Ferodo faces attached to the

pressure plate and clutch cover-plate. It will be noticed in lllustration there is a splined shaft passing through the clutch withdrawal collar, and this shaft enters into the centre plate of the clutch, the centre being also splined as shown.

The operation of the clutch on the modern motorcar is comparatively

;

The withdrawal only needs a little lubricant Excess will be flung on to the clutch plates, which will cause slipping.

52,

which is the clutch housing as

"

U

"

shaped member attached to a shaft which

;

this clutch withdrawal sleeve comes

too much is worse than

it

is as well for a moment

"

U

"

shaped bracket will

NO.

52

that

lllustration

mechanism, and the lubrication point is shown in lllustration No.

52.-View inside the clutch housing showing the withdrawal

56.

Page

Fifty-seven

Clutch

ship of the various parts, he is referred to lllustration No.

Operation.

In order that the owner may understand the relation-

53,

for each part has been photographed in its correct relationship. The parts are also shown in lllustration No.

54,

in this case each one on the clutch parts by different people, but in the as follows

:-

its

own. Various terms are employed to describe

M.G.

Works they are described

First there is the clutch cover-plate

next to

;

that the duralumin centre-plate with fabric facing on either side steel floating plate which contacts with the pressure plate, the rear of which

it

the floating plate ; next to

;

then another

is

into a series of cups to house the clutch springs, and behind this the flywheel.

GUIDE

EEL

4

PRESSURE

PLATE

3

FLYWHEEL

G

CLUTCH

COVER

PLATE

lllustration 53.-Various components of the clutch, showing that there are

two floating steel plates and that the pressure plate is nearest the flywheel.

5

DURALUMIN

CENTRE

PLATE

WITU

..,..,

FABRIC

FACING

FLOATING

PLATE

formed

The driven plates are made of steel, and, as has been previously explained,

are a sliding

fit

on the front end extension of the gearbox shaft. The clutch cover- plate, centre plate, and the pressure plate are each fitted with Ferodo discs, the Ferodo being attached by means of rivets suitably countersunk. There are six clutch

fit

springs which

into recessed cups on the flywheel side of the pressure plate, and

the flywheel is fitted with six guide pins that pass through slots in the pressure

plate, and, when the whole clutch is bolted up, register through holes in the clutch

53

and

cover-plate. These pins are shown in Illustrations Nos.

It

stands to reason that when the clutch

lllustration No.

56

the pressure of the springs will force the pressure plate

is

bolted up solid as shown in

54.

into contact with the driven plate, and grip the latter between the pressure plate and the clutch cover-plate. It

is

essential that the Ferodo rings must be free from any lubricant so that they can work effectively, and one can visualise that letting in the clutch with a jerk may rough up the Ferodo faces. Alternatively, by letting the clutch continually slip, the centre plates will become overheated, which will, in turn, have a detrimental effect on the clutch surfaces.

Page

Fifty-eight

FLYWHEEL

lllustration 54.-Inner view of the clutch and its components. The clutch cover-plate is bolted

to the flywheel and the centre plate 2 registers over the guide pins in the flywheel.

plate

3

is forced rearwards by the action of the springs, when it grips the floating plates 4 and 5 between the friction surfaces on the plates 1, 2 and through holes, one of which is marked

flywheel, thereby compressing the clutch springs.

3.

When the clutch is pushed out, three push pins pass

"

A

"

in the plate

I,

and forces pressure plate 3 towards the

The pressure

Clutch Withdrawal. In order to effect the disengagement of the clutch

it

is necessary to force the pressure plate out of engagement with the floating

plate by compressing the clutch springs.

It

will be seen on reference to lllustration

No. 54 that on the inner side of the clutch cover-plate there are three holes, one of which is marked A, in which short plungers register, which, when the clutch is assembled, come into contact with the three hardened steel abutments marked AI in lllustration No. 54. These plungers are controlled by the adjusting screw carried in the withdrawal arms, which can be clearly seen in lllustration No. 55. Pressure on the clutch pedal forces the withdrawal arms forward, and in turn these

force the adjusting screws against the plungers, which in turn force the clutch

pressure plate towards the flywheel, thus compressing the clutch springs.

it

The action of the clutch thus having been described,

simply remains to show how adjustment is effected, and the reason for the three small springs marked I shown in lllustration No. 55. The springs are only intended to anchor the withdrawal plate to the withdrawal arms.

It

is also necessary to limit the travel of the clutch

pedal so as to avoid the clutch being pushed out too far. As the clutch gradually

wears, the thickness of the Ferodo rings will decrease, which will cause the floating

plates to come nearer to the clutch cover-plate. This necessitates the clutch with-

drawal set screws being adjusted to give a clearance between the fabric face and withdrawal disc. The correct clearance is in. when the clutch pedal is out of engagement.

In lllustration No. 55 a spanner and screwdriver are shown on the adjusting

set screws, access being obtained through the aperture in the upper housing marked

"

clutch oiling and inspection."

for

Illustration

clutch, and above this the clutch housing and withdrawal mechanism. The withdrawal plate is moved forward by the action of the clutch pedal and presses upon a fabric faced ring in the centre of the cover-plate ; this forces the small set screw set screws are fitted into what are known as "toggle arms." which can be adjusted by a spanner and screwdriver through the clutch inspection cover.

55.-Clutch cover-plate as seen from the exterior of the

"A"

forward sufficiently to disengage the clutch. The

ADJUSTER

Illustration

pedal, inspect the left-hand illustration. central portion in the shape of a

hand end of the illustration shows the first motion shaft of the gearbox, the forward

extension of which passes through the clutch and engages with the steel floating plate

by means of splines. The whole clutch mechanism is lubricated from a point behind the clutch withdrawal collar and through the inspection cover. Use small grease gun with non-separating grease.

Sixty

Page

56.-In order to show the clutch withdrawal and the action of the clutch

"

The clutch pedal is coupled to a shaft having a

U,"

this registers in the withdrawal plate.

The right-

DON'T FORGET TO LUBRICATE THE CLtJTCH THRUST RACE

EVERY

2000

MILES (cars with manual gearbox only).

Page

Sixty

A

Manual

length as

Gearbox.

it

differs in many respects from the orthodox type of box. It has been

It

is thought desirable to deal with the gearbox at some

seen that the change speed lever is fitted to an extension to the gearbox lid, and this

is shown removed in Illustration No.

reverse. The gate is marked so that

3rd and top speed gears are.

In order that the reverse gears shall not be inadvertently

it

engaged, the gate is provided with a stop clearly visible. The gears are operated by series of forks coupled to selector rods. These are shown in Illustration No.

The gearbox affords four speeds and

57.

is easy for anyone to see where the Ist, 2nd,

59.

a

lllustration

gearbox is bolted to the flywheel housing, through which the unit support tube passes. The position of the drain plug can be seen and also the small holes of the flywheel housing connecting with the bushes, carrying the clutch withdrawal shaft.

Illustrations Nos.

57.-The external view of the gearbox, showing the position of the oil filler.

57

and

58

also give the owner an idea of the manner in

The

which the selector rods are locked in position when the gear lever is placed in any of the forward or backward positions. The exterior view of the gearbox

it

should be studied, as

shows the filler on the side of the box which acts as an automatic high level, and the drain plug beneath the box which can be removed through the trap door in the undershield by means of a box spanner.

Page

Sixty-one

Illustration 58.-View of the gearbox partially dismantled, showing the flywheel housing. The centre housing carries the reverse gear and the main and layshafts built up on to the rear end cover.

It

layshaft is also mounted on roller bearings.

mainshaft.

will be noted that the spigot on the end of the mainshaft has a roller bearing and the

The third speed gear on the layshaft is always in constant mesh with the third speed on the

The rear end of the engine and forward end of the gearbox are supported in the frame by the tubular member which is located in the bell housing by means of a bolt and set screw on either side. Examination of the illustration will show that the clutch withdrawal shaft is supported in the bell housing. Bushes are located therein by means of set screws, and there is an oil hole in either side of the housing for lubrication of the withdrawal shaft ends.

In dismantling the gearbox there is no necessity to remove the nuts marked

A,

and

it

will be noticed that the rear end housing of the gearbox is provided with lugs, so that the rear end cover cap is removed by tapping on the lugs instead of introducing a tool and damaging the facing.

Steel balls register in slots in the selector rods, and as the gear lever is moved to and fro the balls ride out of one slot and re-engage in another, according to the position of the lever. Looking at Illustration No.

58,

the user can obtain an excellent idea of the gearbox layout, apart from the gears themselves. It consists of three principal parts

;

the front end of the gearbox is formed by the bell housing, the centre of the gearbox acts as casing and a support for the reverse shafting, and the rear end of the gearbox supports the shafts and their gears.

It

will be seen that the first and second speed gears, which are on the left of the picture, are of the straight tooth variety, whereas the constant mesh gears and the third speed gears have the teeth cut at an angle, or what is usually called

"

double helical."

Page

Sixty-two

The principal point to note in this illustration is the gear on the lower or layshaft,

which is indicated in the illustration as

"

floating third gear," which is always in

constant mesh with the third speed pinion on the mainshaft.

Top gear is obtained in the ordinary way by sliding the third gear on the

mainshaft forward, so that the splines on the hub of the gear mesh internally with

it

the constant mesh pinion on the first motion shaft, and

will be noted that the spigot bearing is of the roller type. When, through the movement of the change speed lever, the third speed gear on the mainshaft is caused to slide rearwards, the nature of the tooth engagement will automatically cause the third speed gear on the layshaft to move backwards in unison

;

it

is then that the gear on the layshaft, which has internal cut teeth, engages with a set of teeth on the front of the second speed pinion. When any other gear is engaged except third gear this third gear on the layshaft simply rotates on its sleeve.

In order to make the matter clearer, the user should now refer to Illustration

59,

No.

which shows the layshaft train of gears locked up on a tube removed from the layshaft itself. The layshaft is fitted with roller bearings at either end and over these roller bearings the complete layshaft is fitted.

The internal mesh dog engagements of the direct drive on the mainshaft and

the third speed free sliding gear on the layshaft should be examined.

If

momentary reference is made to Illustration No.

56

it

will be noticed that the mainshaft protrudes through the gearbox, passing through the gearbox front end cover.

,INTERNAL MESH

M

AYSHAFT CONSTANT

GEAR5

.-

Illustration 59.-Another view of the gearbox components. The complete layshaft gears have been removed from the layshaft. mainshaft and the third gear on the layshaft.

\S1

2"“

BEARINGS

/

NOTE

INTERNAL

MESH

3""

/

ENGAGEMENT

CONSTANT

MESH

FITS

BEHIND

ocaDlhrr.

-

3'\

Note the internal mesh engagement of the top gear on the

MESH

FREE

SLIDE

TO

ci

U

DOG

MAINSHAFT

GEAR

COVER

GEAR

STRlhrrn

BALL

BOX

END

Page

Sixty-three

This cover will be seen in lllustration No.

a steel ring with four bolts passing through

59,

and alongside this will be found

It will be noted that this steel ring

it.

is placed behind the front ball bearing on the mainshaft to act as an oil retaining

washer, and

it

to act as registers for the bolts by which the front end gearbox cover is secured.

A

small hole is drilled on the lower portion of the front gearbox cover, permitting

it

will be also noticed that the ring has a number of lips formed upon

a certain amount of lubricant to pass through to lubricate the clutch thrust, which fits over the extension of the cover.

A

gear striker to operate the gears is shown at the lower right-hand corner

It will be noticed that there are two rods above the main-

of lllustration No. shaft which striker in its proper position by the aid of steel balls which

59.

have grooves in them.

These grooves are intended to register the

fit

into a recess in the

gear striker.

Universal Joint and Propeller Shaft.

The tubular propeller shaft is fitted at either end with Hardy Spicer universal joints. The front end of the propeller shaft is castellated and fits inside the castellated end of the universal joint. The object of this is to allow for the end movement of the propeller shaft due to the flexion of the rear springs and the rise and fall of the axle.

It is necessary to keep this sliding coupling joint lubricated, and in lllustration

No. 64 the nipple for this purpose is provided, access to

it

being obtained through a hole in the shaft tunnel. The universal joint proper consists of a plate carrying two jaws, a cross head with hardened steel roller bushes, and the opposite set of jaws attached to the propeller shaft. This can be seen by referring to lllustration

No. 64.

spring-loaded dust excluder cover.

The entire universal joint is enclosed by a pressed steel cover and a

The hardened steel rollers are grooved to receive semi-circular wire rings which prevent them floating outwards. It is essential that this joint should be packed with Hardy Spicer grease, and a one-pound tin would last a very considerable time. The small gun provided in the tool kit should be kept for lubricating the universal joint and clutch thrust.

lllustration

side is the flange having two jaws and carrying the cross head of the universal joint on steel rollers, the other two pins of the cross head being supported in the jaws of that portion of the joint which

is attached to the propeller shaft.

are supplied with half rings which

joint is entirely enclosed by covers held in position by a spring.

64.-Various components of the Hardy Spicer universal joint.

To prevent the steel rollers from being flung outwards the jaws

fit

into the grooves on the rollers. The whole of the universal

On the right-hand

Page

Sixty-four

Rear

Axle.

The external appearance of the rear axle can be seen from

Illustrations Nos. 65 and 65a. The casing consists of a steel stamping forming what

"

is known as the

banjo." The complete differential assembly including the

driving bevel and crown wheel are mounted on the front cover-plate. The rear

cover-plate

is

purely for inspection and dismantling purposes. A drain plug

is provided beneath the axle for draining this from time to time.

CLEAN

OCCASIONAL

INSPECTION

Illustration 65.-View of the rear axle removed from the chassis which needs no description.

The principal detail of the rear axle that the user should note

in which the rear axle

is

filled with lubricant.

Access to the rear axle

-

.

DRUM

. . .

CUT

-

is

the manner

is

obtained

underneath the rear seat, and the view obtained will be as shown in Illustration

No. 65a.

Illustration 6Sa.-Another view of the rear axle, showing the front end housing, on to which the differential assembly is mounted. the filler cap which can be seen, but the level in the axle can be tested simply by with- drawing the level dipstick.

Page Sixty-five

The rear axle is filled by removing

It

is

always advisable when testing the level of the oil in the rear axle to do

this after the car has been running for some time, so that the lubricant has had a

it,

chance of liquifying. By pulling out the level dipstick, cleaning a reading,

it

is

possible to see whether the gear oil

is

up to the right level. Under

and then taking

no circumstances should the car be pushed or the rear wheels rotated while the level is being checked, otherwise a certain amount of the lubricant will be carried round by the gear teeth and the reading nullified.

It is better to pour in a small quantity and again check the level.

This is effected by unscrewing the filler cap through which the level dipstick passes. Always be sure to press the level dipstick down sufficiently for

If, after filling the axle and checking this by means of the dipstick,

clip.

it is found that too much lubricant has been inserted,

it

to register inside the spring

it

is

essential that the drain plug should be unscrewed and sufficient let out to reduce the level to its proper height, otherwise the oil will run along the axle shafts and possibly through the bearings on to the brakes.

Illustration

inspection cover. The bearing clamps should be noted and the position of the lateral adjustment.

Illustration No.

66.-View of the differential assembly that can be obtained by removing the

66

shows the interior of the axle with the gears in position after the rear cover has been removed. It will be seen that the complete differential assembly is clamped in position by two bridge pieces, having nuts of the " ring

"

type on either side ; the object of these nuts is to permit of lateral movement of the unit in order to obtain correct meshing of the bevel gears. Once these have been set at the Works there is practically no necessity ever to remove them, but

it

in the case of an accident

may be found necessary to readjust the mesh for the bevel gears. Of course there must be two adjustments for the meshing of the bevel gears, namely the lateral adjustment of the crown wheel and the end adjust- ment of the driving bevel, permitting

it

to mesh correctly with the crown wheel.

WlTH DRAWN

HUB

COMPLETE DIFFERENTIAL

UNIT

-

LOCKING

AND

Illustration 67.-Rear axle partially dismantled showing how complete differential unit can

be removed, after the axle shafts have been withdrawn with the hubs.

Illustration No.

67

is a picture of the rear axle casing with the complete

NUT

WASHER

differential assembly removed, and one axle shaft and hub removed as well. Before

it

the differential can be withdrawn,

is necessary to withdraw both the axle shafts.

possible to withdraw an axle shaft.

of withdrawer.

Page Sixty-seven

REAR BRAKE

HUB

PARTIALLY

Illustration 68.-This shows that after removal of the brake-drum

DRUM

WlTH SHAFT

WITHDRAWN

AN

This operation may necessitate the use

it

is

Axle Dismantling.

and half-shaft can be withdrawn by refitting a wheel and pulling outwards, and

now examine Illustration No.

through the hollow axle casing, and the inner hub flange runs on a large ball

bearing. This bearing has to be periodically lubricated, which is effected by

forcing a little grease through a nipple on the inside of the hub recess. Under

no circumstances should gear oil be used for this bearing, but on the other hand a grease of the nature of vaseline is essential, as, for example, Shell R.B. This grease will remain in the bearing and not be flung out and find its way on to the

brakes. The ball bearing is locked on the axle tube by means of a ring nut and tab

If

washer. drift and hammer. Steel punches should never be used, except in absolute emergency.

Before the bearing housing is removed

69,

which shows the correct type of tool to use for removing the bearing nut. Primarily, the illustration is intended to show the components of an axle shaft, the outer bearing on which

will also be noticed that there is a felt washer used to prevent oil leakage in the axle.

should have the inner key to register in the keyway with the axle tube intact, as well as the outer lips for registering in the grooves in the bearing nut.

This illustration affords another opportunity of examining the brakes, including

the shape of the cam used, the return spring between the shoes and the pivot pins

on which the shoes articulate. The brake-shoes are held in position by thin nuts, which are split-pinned.

ever the ring nuts have to be slackened they can be driven off by a brass

It

is essential that the lock washer which holds the bearing nut in position

First remove the wheels and brake-drums. The hub

69

carefully. This shows that the axle shaft passes

it

is as well to examine Illustration No.

it

runs in conjunction with the rear hub housing.

It

Illustration 69.-The left-hand illustration shows the type of tool employed for removing the rear axle hub bearing nuts. These bearings are held in position and locked with a tab washer. components of an axle shaft are shown along the bottom of the illustration. The brake mechanism can be inspected in this illustration.

Page Sixty-eight

The

Illustration 69a.

Sometimes an axle shaft can be with-

drawn by taking off a wheel and brake- drum and using a copper hammer as shown on the re- placed wheel nut.

Sometimes a hub will become a very tight

adhere to the hub bearing housing. In such cases

by fitting a wheel locking nut on the hub, giving

fit

;

that is to say, the hub flange will

it

is possible to remove the shaft

it

a good blow with a copper

hammer on alternate ears.

It

is as well to know that the outer ball bearings are provided with felt washers,

or glands, to prevent the grease in the back axle creeping along the axle shafts.

ASSEMBLY

Illustration

the bridge clamp and the lateral adjustment by ring nuts. The correct mesh of the gears is obtained by using shims.

Sixty-nine

Page

70.-Differential and crown wheel assembly removed from its housing, showing The driving bevel assembly is also shown.

Differential.

the complete differential which is shown in lllustration No. 70, after being removed

from the aluminium housing and the bridge pieces which hold

bevel assembly has also been dismantled in lllustration No. and one ball bearing, the bearings being spaced apart by a distance collar. A number of shims are provided to take care of the correct meshing of the driving bevel with the crown wheel. The rear end plate enclosing the whole assembly is provided with tapped holes

noticed having a gap in thus preventing any forward motion of the roller bearing should subsequent wear take place.

be returned to the Factory, where

adjustment of the gears be effected.

After the axle shafts have been withdrawn

$

in. B.S.F. to act as means of withdrawal. A circular steel ring will be

it

which registers in the front of the driving bevel housing,

If

ever the differential assembly needs attention, the whole unit should

it

can be properly looked over and correct

it

is possible to remove

it

in position. The driving

71

;

this runs on one roller

BETWEEN BEARINGS

lllustration 71.-The crown wheel and differential are shown on the left removed from the housing, and the driving bevel assembly is shown dismantled. The bevel shaft is mounted on a roller bearing at one end and radial and thrust bearing at the other.

Suspension.

could be served by repeating illustrations, and in consequence occasionally to refer readers back to an illustration to make the point clearer.

Refer for a moment to lllustration No. spring, and to lllustration No. 10, which shows the rear end of the rear spring. There are no shackles employed in the M.G. Magnette.

The rear end of the front and rear springs slide in phosphor bronze blocks in

the spring anchorages.

upon fixed points. inequalities, the rear end of the springs slide to and fro. The top leaf of the spring is accommodated in split phosphor bronze blocks capable of rotating in their housings. The manner in which this is effected is shown in lllustration No. 72,

which shows a rear tubular frame cross member with the phosphor bronze slotted

bushes in position. These are held in place by a distance piece and the whole assembly locked up by a large nut. A greaser nipple is provided which screws into the

distance piece, and finally the whole assembly is enclosed by means of a moulded

rubber cover as seen in the illustration. The bronze bushes are capable of rotating inside the tube and the spring bushes.

As was mentioned in the opening chapters, no useful purpose

The front end of both front and rear springs are pivoted

As a spring compresses or expands, due to load or riding over

is

also capable of end movement in the slots of the

RADIAL~~THRUST

BEARING

it

is necessary

3,

which shows the rear end of the front

Page Seventy

FLAT

LEAF

DISTANCE

SPRING

\

COM~LETE

LEFT HAND

THREAD

REAR

CROSS

MEMBER

I

\

lllustration No. 72.-The component parts of the rear spring assembly. The trunnions, be seen, are in two parts to allow the spring to be withdrawn from the housing in the chassis frame. Note also the distance piece and cover-plate. The entire assembly is enclosed in a rubber cover

and lubricated centrally from the dash wall nipples.

Wheel

Removal, Brake Details and Front Hubs.

I

ER<NZE

TRUNNIONS

DISMANTLED

The brakes on the front

it

will

and rear axles are similar in design, and the two views, 73 and 73a, are of the front

hub, partially dismantled.

Metal parts that have been bolted tight for a considerable time have the

effect of causing an adherence of two parts, making the ordinary efforts to separate

it

them of no avail. In the case of a hub, tapping a wheel cap in the manner shown in lllustration No. 73.

is possible to make a hub drawer by

Note

:

The rear

hub is fitted on to the rear axle shaft under considerable pressure, so that the

type of drawer illustrated is only suitable for the front hubs.

it

To remove a front hub

is necessary to remove the stub axle nut.

be effected by first of all removing the plug which

is

found in the serrated portion

This can

of the hub, and through this hole the split pin which locks the nut in position can be

It

is

extricated.

sometimes possible by putting on a wheel to pull the whole hub

off. The component parts of a front hub are shown in lllustration No. 73a.

ALWAYS n'l~

ON

THIS SIDE

TO

UNDO

WHEEL

CAP

ADAPTED HUB DRAWER

FOR

BRAKE SILENCER

a

FOR

AWING

_-

lllustration 73.- Details of the brake gear and wheel cap adapted for front

hub withdrawal. Examination of the

steel locking cap

nuts show which is right-hand and left- hand, and the way

the nut should be

hit with the hammer in order to loosen

j

it.

1

i

I

l

I

FRONT

HUB

AND BRAKE

SPRING

TOOL

WHEEL

LOCKING

NUT

Illustration 73a.-Complete details of a front hub. To remove a hub

it

is necessary to take out a plug in the hub shaft, extract the split pin from the stub axle nut, then, after removal of the nut, the hub complete with bearings can be withdrawn. The numbered parts are

of the felt retaining washer distance piece; 7 is a washer with a small key registering in the keyway in the stub axle: and 8 is the axle nut.

2;

4

and 6 are the inner and outer ball races; 5 is a

There is first of all the oil retaining felt washer

I

casings

and 3.

The large ball bearing 4 is then fitted on to the stub axle, next

to this comes the tubular distance piece

:

I

and

3,

inner and outer gauges

2,

and the inner and outer steel

5,

and then the small ball bearing

6,

which is fitted into the outer portion of the hub, the whole unit being locked up by the nut 8 and the washer 7, which has an integral key which registers in a keyway on the top of the stub axle. The tube spanner is necessary to tighten up the axle nut

8,

which must be subsequently split-pinned.

It will be noticed by Illustrations Nos. 73 and 73a that the wheel locking nuts are shaped in a particular manner, and also the threads on the near-side and off-side hub are dissimilar, a left-hand threaded cap being fitted on the off-side. When removing a wheel the blow with the copper hammer should always be dealt on to the straight side of the extension of the cap, and not on the side which is decidedly angular. Both in Illustrations Nos. 73 and 73a the brake silencers have been removed to show how they are fitted, consisting of, as they do, a plate, two

springs, and two pins which are split-pinned in position.

Page Seventy-two

Page

Seventy-two

A

CLUTCH INSTRUCTIONS FOR CARS FITTED

PRE-SELECTOR GEARBOX

CEAR PRE-SELECTOR LEVER

PETRO

CONT

SPEEWMETER REDUCTION B0

PROPELLOR SHAFT FLANGE

BALANCING SPRING HOUSING

CEAR

CHANGING LEVER

WITH

THE

CLUTCH INSPECTION

Illustration

Clutch.

CONNECTING

74.-Showing the clutch connecting link and the method of adjustment.

Before proceeding with adjustment

LINK

it

is as well for a moment to deal with the synchronisation of the main clutch with the pre-selector gearbox clutches. The main clutch is connected to the pre-selector clutches by a link motion, so arranged that on depressing the clutch pedal the first movement disengages the main clutch

it

when further movement changes the gear previously selected, and of course

must

therefore follow that on releasing the clutch pedal the pre-selector clutch engages

it

first, followed by the main clutch. Under no circumstances is

advisable to alter the adjustment of the link motion unless such adjustment be carried out by fully qualified repair dep8ts.

Page Seventy-two

B

Clutch Adjustment.

withdrawal bearing comes into contact. position the clearance between the withdrawal race and withdrawal fingers should be pre-selector gearbox and main clutch. The adjustment to reduce or increase the clearance between the withdrawal arms and withdrawal race is effected from the outside of the gearbox

forward the withdrawal race would be brought closer to the withdrawal levers,

and conversely by adjusting the clutch pedal towards the rear, the withdrawal race would be brought away from the withdrawal levers. In Illustration be seen that the connecting link between the clutch pedal mechanism and the gear changing lever is threaded- for a portion having a nut fitted either side of a stop

bracket, this bracket coming against a stop on the balancing spring bracket, and these nuts are slackened and the bracket moved towards the rear the clutch pedal will be adjusted forward, or allowed to move farther back, care being taken to keep the adjustable stop bracket square with its stop and that the nuts are properly tightened up after adjustment.

".

Illustration No.

There are four clutch withdrawal arms with which the

When the clutch pedal is in the engaged

74

shows the link mechanism between the

;

it

will be easily seen that by adjusting the clutch pedal

No.

74

if

the bracket is moved forwards the clutch pedal will be

it

will

if

Clutch Lubrication.

and

is

packed with non-separating grease when the clutch is assembled. This lubricant

is sufficient for a very long mileage, and attention at this point is unnecessary.

The clutch thrust race has a special grease retainer

CLUTCH INSTRUCTIONS FOR CARS WITH MANUAL GEARBOX

ARE ON PAGES

57-60.

Poge Seventy-two

C

Pre-selector Gearbox.

under Wilson patents, fitted to M.G. Magnette gears requires comparatively little instruction. inside the box during the operation of

The gears work on what is known as the epicyclic principle, or, as they are sometimes called, planetary gears. The gear wheels are always in constant mesh, and the action of the gears takes place by the contraction of a number of brake bands which grip a series of brake-drums or annulli, depending upon the position of the selector lever be operated when the and then the pedal let up in the ordinary way. The term " clutch " pedal is used

in the sense that and, while having the same effect as an ordinary clutch, operates, of course, in an entirely different manner.

How

the hand brake is applied, make sure that the gear is in neutral by moving the pre- selecting lever to the neutral position, and depressing the pedal to its full extent and

releasing

gear position (or reverse, should extent and release as one would when engaging a normal clutch. The car will begin to move in the gear selected.

It

is as well, however, for the owner to know what

;

or in other words, the selector lever predetermines which gear will

'l

it

is the medium which disengages the power from the engine

to

operate the Controls.

it.

Then start the engine and move the pre-selecting lever to the first

it,

controlling the final part of the upward stroke of the pedal

The latest type pre-selector gearbox, manufactured

is

"

de-clutching " and selecting the gears.

clutch " pedal

is

pressed down while the engine is running,

To

start. Before starting the engine, see that

it

be required) and depress the pedal to its full

taking place

To

change gear. Whilst the car is moving forward in 1st speed, select 2nd, and when this speed is required relieve the accelerator pedal, depress fully the pedal and release when starting.

Proceed similarly for the engagement of 3rd and 4th speeds.

When changing up, pedal, and when changing down the accelerator pedal should remain partly de- pressed, and by this method Should the gear fail to engage on account of the pre-selector lever being between the positions indicated, move pre-selector to the correct position, depress and release clutch pedal a second time.

It

is usual to run on top with 3rd selected and ready for an instantaneous change when required. for any purpose will then cause the engagement of 3rd speed, and the engine should be accelerated to ensure a smooth change.

There is no need to change speed merely because the selector has been moved, and selection can be made long before the change is actually required. Early

"

should be kept in mind and driving will become much simpler.

it,

controlling the final part of the upward stroke of the pedal as

it

is

advisable to relieve the foot from the accelerator

it

will be found that the smoothest changes are effected.

It

should, however, be remembered that complete declutching

''

clutch

"Select

"

A

slight pressure on the pedal will give free engine position.

Page

Seventy-three

To reverse. Although reverse may be selected while the car is moving forward, on no account should engagement of reverse

it

be engaged until the car has been brought to rest.

is

effected by the depression and release of the pedal

The

as explained above.

A safety catch is incorporated on the selector lever to prevent reverse being selected by accident.

To stop. Depress and hold the clutch pedal right down before the car comes

it

is

wished to proceed immediately, select 1st speed and engage clutch

to rest. as described in paragraph " To start."

If

If on the other hand a prolonged stop is expected and the driver wishes to release his left foot, neutral must be selected before the pedal is allowed to return. When neutral is engaged the pedal will remain partly depressed.

When changing down care should be exercised to see that the speed of the car is not greater than the equivalent engine speed at

30

miles an hour

it

would not be advisable to change from top into

for example,

if

the car is running

1st

gear,

;

because this would cause the engine to run at a much greater speed than that for

which

of

it

is

steep hill on

30

miles an hour

designed, and

1st

gear with the clutch out, and after the car has attained a momentum

it

would be exactly the same thing as coasting down a

it

would be inadvisable to let the clutch in.

Before attempting to follow the operation of the gears

it

is

as well for the owner

to study the four illustrations A, B, C, D, which show the exterior of the gearbox from four points of view.

bell housing. The input shaft is coupled to the flywheel by means

of a short coupling shaft having rubberised fabric joints.

Page Seventy-four

Illustration

A.-View of the gearbox units attached to the

ENGINE

.-*.lT",,I

UNIT CONTROL

c

TUNNEL

FILLER

PLUG

n

)"

Illustration B.-Near-side of the gearbox showing the position

of the unit control tunnel and the gear selector lever. The principal

points in this illustration which concern the user are the position

of the gearbox filler plug and the level plug

circumstances

should not be over-filled.

LLVLR

must heavy oil be used in the gearbox, and

"A."

Under no

it

Illustration A is a view of the bell housing or flywheel housing as seen after

this has been removed from the engine. The mainshaft is in two parts, so

that

it

is possible for the front end to rotate and for the rear end to remain stationary-that is to say, the in-put shaft, which can be seen in the illustration pro- truding through the front end cover of the gearbox, is coupled up to the flywheel

by a short length of shaft and rubberised fabric joints.

It

will be noted that the

in-put shaft is splined.

The illustration also serves to show the tubular cross member by which the

A

unit is supported in the frame.

In Illustration

the remote control tunnel supports

the selector link which effects the gear selection.

it

The shape of the front end gearbox cover should be noted as

oil pump cover.

The object of the pump is to maintain the circulation of oil

contains the

throughout the whole of the working parts of the gearbox, but the operation of the

pump will be described later. It will be no:iced, however, that there are three rows of nuts in the illustration, the inner circle being used to attach the pump to the housing, the middle row for attaching the housing to the body of the gearbox, and the outer for attaching the bell housing to the gearbox.

We will now pass to Illustration B, which is a view of the gearbox as seen from the near-side. filler plug, which has been shown removed from the filling orifice.

be found the level plug

to Illustration

removing the level plug

The first point that should be noted in this illustration is the

Below this will

These two items can be more clearly seen by referring

A.

Under no circumstances should the gearbox be filled without

D.

A.

Page Seventy-five

The oil should be changed when the car has completed the first

It

should be replenished every 1000 miles, and every 3000 miles the plug at the

1000 miles.

bottom of the gearbox should be removed and the old oil drained out, and the

gearbox subsequently refilled up to the proper level.

Under no circumstances

should thick oil be used.

The action of the gear selector lever can be followed in Illustration

B.

When

the selector control lever is drawn backwards the gear selector lever is moved

it

downwards so that

registers with the aid of a spring-loaded ball in recesses in

a plate.

It

will be noticed that the rod between the unit control and the gear selector

lever is threaded at either end to permit of adjustment should same be necessary on the selector control lever and the gear selector lever. There is no reason for adjustment in the ordinary sense of the word, but

if

the unit has to be dismantled

at any time, the adjustment is provided should the position of the gear selector lever

not synchronise with the position of the selector control lever.

Illustration

of suspension and the short lever which is coupled up to the pedal. When the lever is moved although its operation is entirely different.

C.-Off-side of the gearbox showing the method

it

has the same effect as a clutch,

clutch"

There are two plates and two rows of nuts to be seen on the near-side of the

box which, under no circumstances, require attention.

We will now pass to Illustration

;

gearbox

the principal point to note being the lever which is controlled by the

C,

which is a view of the opposite side of the

pedal. This lever operates what is known as the busbar rocking lever.

The action of the busbar will be explained later, but, in short,

it

consists of a plate coupled up to a spring ; the plate or busbar is caused to move up or down inside the gearbox, depending whether

it

is being pulled up by the action of the spring

or pushed down by the action of the pedal.

Page Seventy-six

The last illustration of the exterior of the gearbox shows what has been

previously described as seen from the rear of the box.

A

;

filler plug and level plug

besides having the number of the gear marked on

selection a matter of some simplicity.

makes

is

it

clear that a slight rocking movement

moved forwards and backwards to make a change of gear. The remaining control

the selector control lever operating in a slot which,

it,

A

little experience in handling the box

is

necessary when the control lever

Illustration D shows the

has stops which make the pre-

levers are neatly arranged around the selector control lever for ignition, carbura- tion and shutting off petrol.

Illustration D.-Rear end view of the gearbox unit showing the controls. link through the control tunnel, and if ever this is dismantled care

should be exercised to see that the adjustment with the length of

the selector link rod is not altered. The remaining controls operating

through the tunnel are the engine slow-running, petrol tap change-

over and the ignition and jet control.

A

selector control lever is coupled up to the selector

There are two things that the owner will probably want to know at the outset

is

namely what happens inside the gearbox when the selector lever fro, and also what happens when the pedal

again. running, or

These two questions can be answered as follows. If the engine

if

the engine

is

running and the pedal

is

pushed down and then let up

is

not being pushed out,

moved to and

is

not

movement of the control lever simply rotates a camshaft inside the gearbox

is

without causing anything to happen, and secondly when the clutch pedal

it

causes a lever to rise and fall in the gearbox to either grip or slacken the

operated

brake bands which will be referred to later. The operations of these two units will be seen on referring to Illustration

E.

Here we see the gearbox upside

down after the contents have been removed.

Page Seventy-seven

Previous reference has been made to the in-put and out-put shafts. They can

be seen in lllustration

E,

wherein the in-put shaft registers in a spigot bush inside the out-put shaft. The train of gears, brake bands and drums have been removed so as to show the shafts and to afford a view of those parts of the gearbox which otherwise could not be seen.

The first question asked was, What does the camshaft do? The camshaft does

not have cams similar to those employed in operating engine valves, but they consist

of

of nicks in circular discs permitting any one of the series

five selector springs

to fall into the notch in the cam depending upon the position of the selector lever.

When the lever is put into position of 1st gear selection the camshaft rotates, allowing the notch in No. all the others, and

No. I train

struts.

A

number of small levers will be seen below the camshaft which act as gear

interlocks, making

it

of

gears to come into operation through the action of the operating

it

impossible for two gears to be engaged at once. Their action is

I

cam to let the selector spring No. I stand proud of

is the action of this spring which will cause the brake band of

entirely automatic, and the manner in which they are worked will be described later.

The second question which was asked earlier was, What is the action of the

clutch pedal inside the gearbox?

it

shows that the "clutch" pedal causes a lever inside the box to move up and down.

lllustration

E

answers this question in so far that

INTER

\SLOT

lllustration E.-Interior of the gearbox, showing the input and output shafts, but without the

actual gears and bands.

To understand the gearbox properly, it is necessary to pedal is to cause the busbar rocking lever to rise and fall. On referring to illustration roller on the end of the rocking lever comes in contact with the boss

B

shows the external view of the interlock and tail-plate bolts.

In this illustration the following parts can be seen: the camshaft, the selector springs and the gear locks. These three parts control the actual gear to be engaged. Rotating the camshaft by moving the selector control lever to and fro permits the selector springs engaging with the operating struts shown in lllustration than one gear being engaged at once.

LOCK

A

/TpPL,GLECTOR

,

CAMSHAFT

read the text.

(2)

on the busbar. lllustration

F,

and the action of the gear interlock device prevents more

The action of the

F

the

Page

Seventy-eight

AUTO ADJUSTER

REVERSE

THRUST

BOSS

WITH

ROCKING LEVER

PAD

ENGAGES

BUS

EAR

ADJUSTER

/

BUS

NUT

BAR

SUPP

ADJUSTING

BRAKE

SET

ANCHORAGE

lllustration

is mounted on anchorage links. Operating struts are caused to rise and fall by the action of a busbar which is under the control of the spring on the bracket pulls on the point mechanism on the top of the anchorage link consists of an automatic adjusting device, to take care

of any wear in the bands and give uniform pressure. When the clutch pedal is pressed down, the

busbar rocking lever forces the busbar outwards, thus freeing the brake band until the pedal is let up again.

This lever is known as the busbar rocking lever.

F.-This is a view of the base of the gearbox on to which the brake band assembly

6;

(3)

when the clutch pedal is in its normal position. Expansion of the clutch spring

(4),

causing the busbar to rise with

the busbar terminates at (I), making knife-edge contact

it

and contract the selector brake band. The

It

will be noted that at the inner

extremity of this lever there is a steel roller let into the fork end of the lever.

Before passing to the next illustration

it

will be remembered that lllustration

E

is the view of the gearbox taken from below, and is really, so far as the reader is

F

concerned, upside down. With this in mind pass to lllustration

and first of all

look at the part marked I Busbar, and then carry the eye along to the point marked

2,

which is a raised track on the busbar which engages with the busbar rocking

lever shown in lllustration

E.

When the pedal is pushed down the rocking lever moves downwards,

pressing upon the point of the busbar marked

(3),

and

it

will be noted that the point of support has a knife edge.

extremity of the busbar, at the point

5,

spring compression lever

which is clearly under the action of the spring

4,

It follows, therefore, that when the pedal

2.

The busbar pivots on supports

The outer

is coupled by means of a link to the

6.

is

pressed down the busbar is forced downwards, thereby compressing the spring, and when the pedal is let up or back, the spring

causes the busbar to rise, carrying with

it

one of the

6

operating struts which through the action of the various linkages at the top will cause one of the brake bands to contract. The busbar has a groove running the complete length, and when the selector lever is in neutral the 1st and reverse struts are engaged, and owing to the action of the gear interlock neither strut can reach the engaged position and the busbar will remain partly depressed.

Page Seventy-nine

I

NUTS

ENGAGED

AUTOMATIC

ADJUSTER

AND SPRINGS

l

OPERATING

STRUTS

3RD

SPEED

FNGAGED

\

B&

BP

ADJUSTER

/SET SCREW

Illustration

struts quite clear.

is forced upwards, while the other struts are free of the busbar and do not engage with it at all. The action of the busbar rising can be seen by referring to the right-hand illustration. that the adjuster set screws on the bands are all free of the adjuster nut, except the third gear, which

has been forced up against the adjuster set screw by the action of the busbar.

A

side view of the bands and operating mechanism can be examined after the

gearbox casing has been removed from the base plate. In Illustration

through the action of the spring, is in the up position, and

G.-The left-hand illustration will make the action of the busbar and operating

It will be seen that the second strut from the left is engaged by the busbar and

It

will be noted

G

the busbar,

it

will be noted that the 3rd speed actuating strut has been engaged with the groove in the busbar, and has been forced upwards while the other operating struts are entirely free of the busbar's action. The whole action of the busbar is to spring load the brake band contracting levers or linkages so as to cause the bands to grip the drum.

The first question that was asked was, What was the action of the camshaft?

it

is

This action will now be made clear when

realised that the flat springs inside the box, which are allowed to move forward when they drop into a notch in the cam, come in contact with the operating struts, with the result that when the

is

pedal is pushed out and the busbar

allowed to fall, the spring will force the operating strut sufficiently far forward to engage with the groove in the busbar and allow the particular pre-selected gear to come into operation. Carrying this further, the true understanding of the pre-selector gearbox will be grasped. Suppose, for example, that the car is running in 3rd gear, the busbar will be up and the 3rd speed brake bands will be contracted. The action of rotating the cam-

shaft by moving the selector lever will have no other effect than causing the springs

to move forward and backward, with the result that they will simply press up against the operating struts which are lying idly in the box. These operating struts cannot engage with the busbar because, on referring to Illustration will be seen that

it

is necessary for the busbar to drop considerably first.

G,

it

When the busbar does, however, drop through being forced down by the pedal, and another gear has been pre-selected, the small spring contained in the linkages of the operating struts will throw the strut that has previously been in operation outwards free of the busbar, and then the action of the flat selector springs on the

Page Eighty

side of the box will cause the next pre-selected gear strut to be forced forward

or towards the busbar, so that

it

in turn will engage with the groove of the busbar and in turn will be forced upwards and cause the particular band of the pre-selector gear to be contracted.

On the right-hand side of Illustration G

it

is possible to examine the interior

of the gearbox as is shown when the top cover is removed. The top cover is formed

in the case of the M.G. Magnette by the unit control tunnel mounting, and in this illustration the 3rd speed engagement that was shown previously is viewed from

above. The two further points that can be seen in this illustration are what are

known as the adjuster set screws and the adjuster nuts. The object of these is to permit of the wear that takes place on the brake bands being automatically com- pensated for by a corresponding shortening of the link which is attached to the brake band at the lower extremity and to the adjuster nut at the upper extremity.

H

Illustration

is a close-up view looking inside the gearbox after removal of

the cover. It will be noted that the adjuster nuts can be seen in Illustrations

F

and G, screwed on to a link, and beneath the nut there is what is

Illustration H.-View that can be obtained after removal of the gearbox cover lid. the arrows to these parts spring, then note the slot in the adjuster ring, and the part marked FP, i.e. fixed pin, in the opposite

half of the adjuster ring. Unless proper advice is obtained from somebody who knows definitely what

the action of the adjusting set screw really is, under no circumstances should these be touched. They

have a definite function to perform, but it has nothing to do with the actual contraction of the brake bands ; they form stops up against which the adjuster ring abuts, so that when a gear is engaged,

the adjuster ring is forced up against the stop and a certain angular motion is imparted, causing the

adjuster plate to pivot around the nut to the limit of the slot. The manner in which the spring is actually round the nut, when the clutch pedal is pushed out, will cause the adjuster ring to move outwards against the tail plate and rock the adjuster ring in the opposite direction, when it comes in contact with the adjuster set screw. This to and fro action causes the spring surrounding the automatic adjuster nut to grip its length of travel and automatically maintain proper adjustment.

If there is any semblance of drag or lack of quick response, when the clutch is let in "pump

clutch pedal, which means pushing

:

automatic adjusting nut, adjuster ring, adjusting set screw, tail plate, and

it,

which will cause

it

in and out fully several times quickly to take up any slack.

it

to rotate slightly on its bolt and so shorten

Page

Follow

Eighty-one

"

known as an auto adjuster ring and below this an adjuster table.

it

ring has a special shaped pin let into one side of

and a hole on the other side through

The auto adjuster

which a pin, riveted into the adjuster table, passes. Surrounding each nut there

is a spring specially coiled. The object of this spring is to grip the circular adjuster nut. This is effected by the shape and an action of the adjuster ring. It will be noticed that these are tapered at either end. with what is known as the brake band adjuster screw.

F

will show these screws and their relationship to the brake band. They are

The centre adjuster ring is contacting

Reference to Illustration

virtually abutments or stops against which the adjuster ring rests when any particular gear is engaged.

In Illustration H the centre gear is obviously engaged. As wear

takes place the two angular faces of the adjuster set screw and adjuster ring at the

time of engagement will cause the adjuster ring to pivot slightly. This action,

owing to the shape of the spring, will cause

it

to rotate around the adjuster nut. When another gear is engaged and the whole unit is forced outwards, the opposite end of the adjuster ring will come in contact with what and rock the adjuster ring in the opposite direction and tend to tighten

is

known as the tail plate

it

round on the thread of the link. By this means the brake bands are being constantly kept in correct adjustment, and should for any reason a band slip when engaged,

it

is only necessary to move the pedal fully abwt twenty times to and fro for

the automatic adjuster to take up the slack.

As in every other form of mechanism, excessive wear can be caused

by abuse, and it

reduced before the next gear

is

advisable in changing up to allow the engine speed to be

is

engaged, which

is

done by lifting the accelerator pedal while the clutch pedal is depressed and not re-accelerating before the bands have had time to grip the drums.

TOP GEAR

ENGAGING

THREE

CLUTC

TOP

SPEED

ACTUATION

Illustration K.-The front end of the gearbox with the cover removed and complete brake- drum assembly withdrawn to show the brake bands in position. The oil pump is fitted on to the front cover and is driven by an eccentric on the front end input shaft. and is delivered to the hollow shaft, so that all the gears are constantly lubricated.

LUG

BELL

HOUSING

STUD

\

OIL

BRAKE

ilN

OIL

PUMP

BANDS

POSITION

PASSAGE

CAMSHAFT

FRONT

SPl

N

DLE

Oil is drawn from the gearbox

COVER

Page

Eighty-two

TOP SPEED TOP

ACTUATING

RI

OUTER

NG

INNER

SPEED

RING

TOP GEAR

ENGAGING TOP

/

LUG

/

SPEED

CONE

lllustration

strung out to show the internal gears, the top speed cone engagement with the third speed drum, and the manner in which the top speed is actuated by its steel balls, forcing the top speed inner ring

forward under the action of the helical ball tracks, and the top speed actuating outer ring.

L.-Complete set of brake-drums and epicyclic gears. The parts have been slightly

Having thus described the details of the operation of gear selection and the

manner in which the bands are caused to contract, lllustration K should now be

studied. The next point is to see how the gears are built up into a unit on the in-put and out-put shafts, and how the various gears are operated. lllustration K shows a gearbox partially dismantled. The front end cover of the gearbox has

been removed, and is shown on the right-hand side of the illustration. This forms a housing for the oil pump, which can also be seen complete with its housing. The front end of the in-put shaft is provided with a cam-shaped extension or eccentric

which fits inside the

pump plunger extension, so that with every revolution of the engine a plunger which fits into an oscillating housing is caused to rise and fall. This sucks up oil through a small hole in the body of the gearbox, and as the pump oscillates and closes up the suction hole, the downward stroke of the pump plunger forces oil up through the hollow plunger into the hollow gearshaft, and is so distributed throughout the whole inner works of the box.

After the front end cover has been removed

it

is possible to withdraw the

complete train of gears and shafts as shown, presuming that the box has been removed

from the chassis.

The brake-drums can be clearly seen, which operate through

the action of the brake bands of the reverse, Ist, 2nd and 3rd speed gears. The

is

top speed, however,

K

the mechanism of the top speed can be seen. There

differently operated. On the left-hand corner of lllustration

is,

in point of fact, an actual conical engagement of the top speed cone and the Ferodo facing of the inside of the 3rd speed brake-drum. This is not brought about directly by spring pressure, but by the action of the top speed actuating outer ring, which is held stationary up

against the front end cover by means of three set screws and the steel balls which are positioned in helical slots.

Page Eighty-three

Reference to Illustration L shows the train of gears, brake-drums or annulli after the drums have been slightly drawn apart to show the inner planetary gears. This illustration also shows the top speed cone and the helical ball tracks which, when top speed is engaged, cause the cone to travel forward on the shaft and engage with the Ferodo facing on the inside of the 3rd speed brake-drum. When top gear is engaged, the whole train of gears and drums rotate as a single unit, there

being no gear movement at all. It will be seen from this illustration that the shaft

is supported by radial and thrust bearings, the rear end bearing, however, only being

visible. The rear end of the out-put shaft is provided with a keyway for fitting a gear wheel to drive the speedometer.

The following points should be carefully observed by the Driver

Always feel that the pre-selector lever is well in its notch opposite the desired gear before actuating the pedal.

Always depress the pedal to its full extent when making a change of gear, and do not rest your foot on the pedal after the change is made.

it

Always remember that

is the end of the upward stroke of the pedal which decides the smooth engagement of the gear. Therefore, control this part of the stroke of the pedal carefully with your foot.

Before leaving the car always make sure that neutral is not only selected but engaged by fully depressing the clutch pedal with neutral selected.

IMPORTANT.-K. Type cars fitted with the pre-selector gearbox

have an oil pump fitted inside, which operates only when the car is in gear. These cars therefore

must not be towed, unless the

propeller shaft is disconnected. Failure to do this will cause

the gearbox to seize, as when the gear lever is in the neutral

position the oil pump does not function and seizure takes place.

Adjustment to Steering Gearbox.-The

which control all that can be required.

I.

Adjustment for end play of cam.

2.

Adjustment of

m.1

.v......

fit

between follower and cam.

adjustments are two in number,

They are as follows

:-

.a"=-

-.

,

Various sectional views of the Marles-Weller steering gear, parts of which are referred to

Page

Eighty-four

in the text.

..

Adjustment I.-Referring to the illustration

it

will be noted that a series of shims are located between the end cap and the face of the steering box. Remove one or more of these shims as required until the end play disappears, care being taken to see that when the end cap is securely rebolted, the thrust bearings are

still quite free to rotate. Care should also be taken to see that the joint between the end cap and the box is properly re-made if oil leakage is to be avoided. The gear should be filled up with oil to replace any loss during adjustment.

Adjustment 2.-Adjustment for play between the follower and track, although very seldom required, and not at all until the car has been in use a considerable time, is effected by renewal of the hemispheres, those on one or both sides of the follower being changed according to the degree of adjustment required. Remove

cover-plate and drain off sufficient oil to expose the cam and its track.

Withdraw the follower from its bearing on the rocker-shaft.

Replace one pair of hemispheres from one side of the follower by a new set,

and then insert the follower unit into the cam track in its mid position, i.e. approximately midway between the two ends of the cam. This, for the moment, should be done independently of the rocker-shaft, which should be moved over to one side to leave the centre portion of the cam track exposed.

Should further adjustment be required, the remaining set of hemispheres

should be replaced in like manner.

Correctly adjusted, the follower unit should be a free sliding fit in the centre

portion of the track to ensure a free passage of oil between the surfaces, but only

fit

a minimum of sideplay should be permitted. Too close a steering. This point determined,

it

now only remains to replace the follower unit

will result in a stiff

through the rocker-shaft and into the track. This is most easily done with the

rocker-shaft over in the extreme lock position, as the track is purposely made slightly

wider at these points. A little care should be exercised here, and the hemispheres

may with advantage be slightly tilted in their seatings to give a lead-in effect when entering the track. A slight to and fro movement of the steering wheel in con- junction with a light pressure on the back of the follower facilitates this assembly.

When inserting a new set of hemispheres see that they are quite clean and free from grit before inserting them into the follower. A smear of thick grease

in the seatings will check any tendency for them to fall out.

The cover-plate and its shims should next be replaced, taking care to re-make

the oil joint properly, and the gear filled up with fresh oil.

General Notes.-The shims between the cover-plate and the box should not

be removed.

They are intended for initial assembly only.

A certain amount of

end play is called for, and is desirable in the rocker-shaft, and no attempt should

be made to take up this by removing the shims.

Should the thrust bearings be, for any reason, taken off the shaft, care should

be taken to replace them the right way round. The right way round is when the

"

word

thrust " stamped in one side of the inner race of the bearing is up against

the end of the cam.

Page

Eighty-five

MG Magnette KA, Magnette KD Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

MISCELLANEOUS DRIVING HINTS

FOREWORD

CHASSIS DETAILS

steering arm.

how the brakes are

The steel adjusting screw on the outside of the carburetter is only intended for slow-running

COIL IGNITION INSTRUCTIONS

H-Rotating distributor arm.

Test the coil independently of the distributor as follows :-Remove the cable

IGNITION

ever the differential assembly needs attention, the whole unit should

CLUTCH INSPECTION