Mitsubishi 4DQ5 Repair Manual

SERVICE

MANUAL

MITSUBISHI DIESEL

4

ENGINE

5

GENERAL

INDEX

MAJOR DATA AND SPECIFICATIONS

DISASSEMBLY

INSPECTION AND

REASSEMBLY

LUBRICATING SYSTEM

COOLING SYSTEM

FUEL

ELECTRICAL SYSTEM

BENCH TEST

MAINTENANCE STANDARDS

SYSTEM

REPAIR

..........................................

..............................................

5

8

16

37

49

52

56

71

87

89

SEALANT APPLICATION DATA

TIGHTENING TORQUE

SPECIAL SERVICE TOOLS 105

TROUBLESHOOTING CHART

.............................................

102

103

110

GENERAL

1. Major

1-1

component

Left-hand side view

parts

1-Water

pump 2-Fan 3-Fan

belt

4-Fuel

injection 5-Fuel feed 6-0il

pipe

7-Fuel

inlet 8-Fuel feed 9-Fuel

filter

pump

connector

pipe

10-Fuel

injection

11-0il

filler

injection

12-Fuel

13.Rocker 14-lntake 15-Fuel 16-Cylinder 17-Adjusting 18-Hanger

manifold

leak-off

cap

cover

head

lever

-1-

nozzle

pipe

19-Cran kcase 20-Flywheel 21-0il

pan 22-Drain 23-Control 24-Governor 25-Starter

plug

housing

rack

402500

stopper

1-2 Right-hand side view

l-Cylinder 2-Crankcase 3-1

ndicator 4-Flywheel 5-Rocker 6-0il 7-Breather 8-0il

cover

filter

filler

head

switch housing

9-0il

filler 10-Exhaust ll-Elbow l2-Screw 13-Water 14-Fan l5-Fan 16-Alternator

plug

pump

belt

-2-

cap

manifold

l7-Alternator 18-Timing 19-0il

level gauge

20-0il

pipe

21-0il

bypass alarm

22-0il

pan

23-0il

pipe

gear

402501

bracket

case

switch

1-3

Longitudinal sectional view

1-Rocker 23-Thermostat 4-Exhaust 5-lntake 6-Water 7-Piston 8-Camshaft gear 9-Fan

cover

Thermostat

valve

pump

case

10-Connecting rod 11-Cran

kshaft

gear

shaft

kcase

shaft

head

pu

case

bracket

12-Crankshaft gear 13-Timing 14-Rocker 15-Rocker 16-Valve push rod 17-Cylinder 18-Cran

-3-

lIey

19-Tappet 20-Camshaft 21-Crankshaft 22-Flywheel 23-Flywheel 24-0il

strainer

25-0il

pan

26-Drain plug

402502

housing

1-4

Transverse sectional view

1-Exhaust 2-Piston 3-Valve push rod 4-Connecting 5-Tappet 6-Camshaft 7-0il 8-0il

manifold

rod

level gauge pump

9-0il

strainer 10-Rocker 11-Rocker 12-Glow 13-Fuel 14-lntake 15-Fuel 16-Cylinder

plug

injection

-4-

arm cover

manifold

head

nozzle

pipe

17 -Cran kcase 18-Fuel

injection 19-Fuel feed 20-Starter 21-Cra n kshaft 22-0il

pan

402503

pump

MAJOR DATA AND SPECIFICATIONS

Engine model

Type

of

cylinders-arrangement 4-in line

No. Bore x stroke mm (in.) 84 x

displacement

Piston Compression ratio Compression pressure Firing order Direction Burns (fuel) Grade No. 2D diesel fuel (ASTM specification) Engine oil

Dimensions Overall width mm (in.) 562 (22-1/8)

ca

..

a.I

=

a.I

(.!)

Weight, dry Cylinder sleeves

No. rings

Valve arrangement

Valve timing

Valve clearance (both intake and exhaust valves) (cold)

Starter

Fuel feed pump

Fuel injection

5

pump

"til

~

a:i

::I

r-

Governor

Fuel injection

nozzles

of

piston

Intake valves

Exhaust valves

rotation Counterclockwise

Overall length 717.5 (28-1/4)

Overall height

Compression rings 2 Oil ring

Open at: Close at: Open at: Close

Model Cam

lift mm (in.) Model Plunger diam mm (in.) Plunger lead Cam lift Model Type Type Type

of

nozzle holders

at:

cc(cuin.)

cm

2 (p si)

kg/

kg

(lb)

mm (in.)

Water-cooled, 4-stroke, swirl-combustion chamber type diesel

26 (369.7), min (at

Class-CC

or better (API service classification)

Dry type made or integral water-jacket type

RUV (for prime power)

Centrifugal flyweight, all-speed

40Q5

94

(3.307 x 3.701)

2084

(127.l)

21

: 1

150 ~ 200 rpm)

1-3-4-2

as

viewed from flywheel side

629.5 (24-3/4) 200 (441)

of

special cast iron

1 (w/spring expander)

Overhead 30°

BTDC

50°

ABDC

74°

BBDC

30° ATDC

0.25 (0.0098)

Electric

ND-EP/KS22A

(0.24)

6

PES4A65B

(0.256)

6.5 Right

(0.31)

8

Throttle

CA

Bosch

1 7SD

-5-

Engine model 4DQ5

Type

of

nozzle tips

~

Fuel injection

~

nozzles

~

'1:l

=

""-

Fuel filter Paper-element type

Oil

pump Capacity at oil temp.

e

III

~

Oil

>.

'" '"

=

.sa

~

.~

'"

..

3

e

III

~

>.

'"

pressure

Oil

filter Paper-element type

Relief valve

Refill capacity

Oil

bypass

valve

Water pump

Thermostat

'"

.Sf

'0

0

Fan

U

Drive belt

Refill capacity (engine water jacket)

Spray hole diam mm (in.) Spray angle

Injection pressure

Type Speed ratio

50 ± 5°C (122 ± 9°F); pressure 3 kg/cm (42.7 psi)

At duty run At idling 1 - 2 (14.2 - 28.4)

Type Piston-valve Valve opening

pressure Oil pan Oil

filter Type Piston-valve Valve opening

pressure Type Speed ratio

Capacity Type

Valve opening temperature 76.5 ± 2°C (169.7 ± 3.6°F) Valve lift temperature Type No.

of Outside diameter Ratio to crankshaft speed 1.3 Type Low-edge cog B No.

of

to

crankshaft

to

crankshaft

blades 6

belts 1

kg/cm2 (psi)

liter (cu in.)/

2

min/rpm

2

kg/cm

kg/ cm 2 (psi)

liter (U.s. gal)

kg/ cm 2 (psi) 0.8 - 1.2 (11.4 - 17.1)

liter (cu in.)/ min/rpm

mm (in.)

liter (U.S. gal)

(psi)

Bosch

ND-DNOSD21 1 (0.04)

0°

120 +18 (1706 +

Trochoid

1/2

8.37 (510.8), min/lOOO (pump rpm)

3

- 4 (42.7 - 56.9)

± 0.2 (42.7 ± 2.8)

3

6.5 (1. 7)

0.7 (0.18)

Centrifugal type

1.3

(6408)/3900 (pump rpm)

105

Wax

90 ± 2°C (194 ±

Circular-arc pusher type

380 (15)

4.5 (1.2)

14

6 )

3.6°p)

-6-

Engine model

Working voltage volt Polarity

Type

Glow plugs current ampere

....

=

cv

S

.9-

Starter

i

co

.l:t

...

....

<:J

~

Alternator Manufacturer Mitsubishi-Electric

Regulator

Rated voltage -

Resistance at normal temperature

Model Type Manufacturer Voltage-output

No.

of

pinion teeth/

No.

of

ring gear teeth Model A001T25070 Type 3-phase

V oltage-ou

Rated speed Working speed Speed ratio to crankshaft 1.68 Type Regulated voltage volt

tpu

t

volt -

ohm

Totally enclosed, drip-proof, pinion-shift type

with overrunning clutch

volt kilowatt

volt ampere

rpm

Negative

Sheathed

10.5 - 8.3

M002T54172

Mi

tsu b

12

1000 ~ 13500

IC

type built in alternator

4DQ5

12

(-

1.26

ishi-

12

- 2

11/121

AC

- 35

5000

14.4

) ground

Electric

type

± 0.3

-7-

(1) Drain the oil.

(2) Remove the fan belt and alternator

(a) Loosen bolt

and alternator, and remove

(b) Remove

(1) securing fan belt adjusting plate

fan

bolts (1) and (3) and remove alternator.

as

follows:

belt (2).

DISASSEMBLY

(3) Remove the starter

(a) Loosen attaching nuts (1).

(b) Remove starter from rear plate.

(4) Remove the fuel filter

(a) Disconnect fuel feed pipes (1) (2).

(b) Loosen attaching bolts (3) and remove fuel filter

(4).

as

follows:

as

follows:

-8-

(5) Remove the injection pipes and injection nozzles

follows:

(a) Loosen connectors

pipes

(2).

(b) Remove fuel return pipe (3) by loosening union

nut. (c) Loosen nuts (4) and remove fuel leak-off pipe (5). (d) Remove nozzle assemblies.

(6) Remove the lube oil pipe from injection pump.

(1) and disconnect injection

as

(7) Remove the water pump pulley and crankshaft pulley

as

follows:

(a) Loosen water pump shaft nut

water pump pulley (2).

(b) Loosen crankshaft nut (3) and remove crankshaft

pulley (4).

(8) Remove the timing gear case.

(9) Remove the rocker cover.

(1) and remove

-9-

(10) Disconnect the water pump bypass hose and oil

pipe. To disconnect bypass hose, displace thermostat elbow and water pump clamp.

(I

1) Remove the water pump (a) Loosen attaching bolts (1).

(b) Remove water pump assembly (2).

as

follows:

as

(12) Remove the rocker shaft assembly

(a) Loosen union nut (1).

follows:

(b) Loosen short bolts (2) and long bolts (3).

(c) Remove rocker shaft assembly (4).

"0"

rings

valve

(2 pcs - to

caps.

as

(d) Remove oil pipe (5) and

be

replaced with new ones).

valve

(e) Remove (f) Remove intake manifold.

(13) Remove the cylinder head assembly

(a) Loosen cylinder head bolts (1). (b) Remove cylinder head and gasket.

push rods and

follows:

-10-

(14) Remove the oil pan and oil pump assembly

follows:

(a) Loosen attaching bolts and remove oil pan (1) and

gasket.

(b) Loosen attaching bolts and remove oil pump (2)

assembly.

as

(15) Remove the timing gear train

(a) Loosen idler gear bolt (1). (b) Remove thrust plate (2) and idler gear

(Draw idler gear while twisting it in the direction of

its helix.) (c) Loosen injection pump drive gear nut (4). (d) Remove injection pump drive gear (5).

(16) Remove the camshaft assembly

Take out camshaft assembly (1) from crankcase.

as

follows:

as

follows:

[NOTE]

There are tappets in crankcase; this makes it !}ecessary to turn crankcase upside down when removing camshaft assembly.

(3).

(17) Remove the front plate and injection pump

assembly

(a) Loosen attaching bolts (1). (b) Remove front plate and injection pump

as

assembly.

follows:

-11-

•

..

.

..

~

......

@l

.

.,

(18) Remove the flywheel and rear plate.

(19) Remove the connecting rod bearing caps and

bearings (lower shells) by loosening attaching bolts.

(20) Remove the connecting rods and pistons.

(21) Remove the main bearing caps by loosening

attaching bolts.

-12

-

(22) Remove the crankshaft.

(23) Remove the main bearing shells.

(24) Disassemble piston and connecting rod

(a) Remove compression rings

by using piston ring tool (A).

(b) Remove oil ring spring.

(c) Remove snap

(B).

rings

(3) by using snap

(1) and oil ring (2)

as

follows:

ring

tool

-13-

(d) Remove piston pin (4) by using drift (C). (e) Remove piston pin bushing and connecting rod

bearing (upper).

(25) Disassemble the rocker shaft assembly

(a) Remove snap (b) Remove rocker assembly (2). (c) Remove rocker bracket (3). (d) Remove rocker assembly (4). (e) Remove spring (5).

rings

on both ends (1).

as

follQws:

(26) Disassembly the cylinder head

(a) Remove nozzle holders.

(b) Remove

(c) Loosen bolts (2) securing exhaust and intake

manifolds.

(d) Remove exhaust manifold (3).

(e) Loosen thermostat cover bolts and remove

thermostat cover (4).

glow

plugs

(l).

as

follows:

(f) Remove thermostat (5).

-14-

(g) Remove

(Depress valve spring

valve

cotters (6).

by

(h) Remove retainer (7).

(i) Remove valve spring (8).

G)

Take

out

valve (9).

(k)

Remove

valve

guide by using valve guide

remover (A).

valve lifter.)

-15

lO-Valve guide ll-Cy

Ii nder head

A-Valve guide remover

-

Cylinder head

(1) Inspection

INSPECTION AND REPAIR

Check the gasketed surface flatness in the case

check is

jets removed.

Use necessary,

(2) Precombustion chamber

Do placed. To remove the in

by

using a straightedge and thickness

of

checking the crankcase surfaces. This

to

be made with the precombustion chamber

a surface grinder

to

the specified flatness.

Specifications Unit: mm (in.)

Item

Warpage surface head

not remove the jets unless they have to be

it, drive it

of

gasketed

of

cylinder

out

with a drift pin

jet

of

the cylinder head for

to

reface the cylinder head,

Standard

O.OS,max

(0.0020)

jet

replacement

as

when cracks are noted

of

about 6 mm

0/4 in.) diameter inserted through glow plug hole,

as

shown.

gauge

Repair limit

0.20

(0.0079)

re-

as

B-

L...::t=---

.....

--_

I

....

~

o

Checking cylinder head gasketed surface for flatness

...

·F

A·lntake B-Exhaust

port

C·Jet

-16

Removing precombustion chamber jet

Direction of precombustion chamber jet

orifice

in

installed state

-

©

Valve guides

(1) Check each valve for carboning, burning, wear

other for cracks. Replace the valve

(2) Check each valve guide for wear. Remember, the

guide wears down more rapidly than

meter part meter exceeds the repair limit in Table below, replace the valve guide.

and

valve seats

defect

on

at

any

other

of

the guide

in

two

directions. Measure the outside dia-

of

each valve stem.

head; also check cap

if

parts. Measure the inside dia-

at

its ends and a t its middle

If

end

damaged.

at

its

both

the measurement

and stem

ends

or

,

)

~:

Wear

on

valve guide

(

,

.

:~

(3) Valve face and valve seat

Check contact. reface valve, proceed

valve face and valve seat for wear and

If

valve face is found excessively worn,

it

by

using a valve refacer.

as

follows:

Item

Angle

To

reface the

Clearance of

valve stem in valve guide

Valve guide

length outside hole

Valve stem diameter

Specifications

Nominal

value limit

30°

Standard

Repair

Item

Specifications

Intake

Exhaust

Intake

Exhaust

Unit: mm (in.)

Standard

0.055 -0.OS5

(0.00217

(0.00276-0.00413)

(0315

-0.00335)

0.070-0.105

18

± 0.3

(0.709 ± 0.012)

S

-0.045

-0.060

-0.00177)

.

-0.00236

8

-0.060

-0.080

-0.00236)

. -0.00315

Service limit

Repair

limit

0.15

(0.0059)

0.20

(0.0079)

-0.10

(-0.0039)

-0.15

(-0.0059)

Unit: mm (in.)

Valve seat

Valve margin

Sinkage

Width

O.S

1.4

1.7

(0.031)

(0.055)

(0.067)

±0.2

(±O.OOS)

±0.14

(±0.005S) (0.063)

-17

1.3

(0.051)

1.6

Reface up

1.2

(0.047)

-

Valve seat

to

angle l

~

~~~

C:J~

~I~am

~

t Valve sinkage 1

Counterbore

n

Face i

Valve

margin

Valve refacer

Set a valve refacer

(a) (b) Grind the valve stock

is

margin the valve.

Valve seat cutter

Repair

valve

(c)

When

as prevent uneven cutting. After cutting, reface the seat by rotating the cutter with No. sandpaper put between the cutter and seat.

(d)

If

30-degree cutter.

1.6 seat. Also replace the seat when exceeds

Valve

seat

less than

an

excessively worn

seat grinder

using a valve seat cutter, exercise

to apply a uniform pressure to

valve

seat width is overcut,

mm

(0.063 in.) due to wear,

1.3

installation

mm

(0.051 in.).

to

an

angle

of

45 degrees.

to

a minimum and,

1.2

mm (0.047 in.), replace

valve

seat by using a

or

valve

seat cutter.

repair

If

valve

seat width exceeds

valve

it using a

rep.lace

valve

if

the

care

so

seat to

400

the

sinkage

Chill the valve seat inserts in ether or alcohol containing

of

in

80°C

the

dry ice. Heat the cylinder head to a temperature to 100°C (176°p to 212°p). Press the inserts cylinder head by using the insert calking tools (3069102700 for intake valve, 30691-02800 for exhaust valve). Leave the cylinder head and the inserts in the air until

shrinkage-expansion fit

is

obtained between the two. Calk around the inserts with the insert calking tool to machine the seat width.

(NOTE]

The insert calking tool may be used pressing and calking the reversing the calking ring.

valve

seat inserts

both

for by

-18

-

'Valve springs

Inspect each spring for cracks, and check it for squareness, free length and as-installed length against these specifications:

Specifications

Item

Valve spring free length

Valve spring squareness

Load compress spring initial working lenfth

[43 mm (1.69 in.)

kg(lb)

to

Standard

48.85

(·1.9232)

1.5°, max

19 ± 1

(41.9 ± 2.21)

Unit: mm (in.)

Repair

limit

47.6

(1.874)

15

(33.08)

Checking valve spring

Exhaust manifold

If

the flange faces are

(0.0079 in.) when

and flat. manifold_

If

checke<;l

any flange is

warped

by

as shown, grind

found

cracked, replace the

more

than

them

0.2 mm smooth

Checking exhaust

-19

-

Checking

valve

spring for squareness

manifold flange surface for flatness

Cylinder sleeves

(1) Using a cylinder gauge, take ID measurements in

to

two directions (parallel and transverse shaft axis) indicated

If

wear reaches the repair limit, reb ore the sleeve

to the

on

each cylinder sleeve, at three places

below.

crank-

Specifications

Item Standard

84

+0.035

Cylinder

Out

roundness

Taper

(2) There are three oversizes for cylinder sleeves,

(3) An oversize to which any sleeve worn taper and/or

sleeve ID

of

ly, +0.25 mm (0.0098 in.), +0.50 mm (0.0197 in.) and

+0.75 mm (0.0295 in.). The tolerance to which

the sleeves should be refinished by boring

0.035 mm (0.0014 in.). When the sleeves are bored, oversize pistons and piston rings should be used.

out

of

round

by relying

cylinder sleeve whose abnormal wear (0.0157 in.) should be rebored to 1 mm (0.0394 in.) oversize, for example.

(3.307 +g.00138)

is

to be rebored should be determined

on

the most worn part

0

0.1

(0.004),

max

0.015

(0.0006),

max

Unit: mm (in.)

Repair

limit limit

+0.20

(+0.008)

is

0 -

of

the sleeve. A

is

0.4 mm

Service

0.70

(0.0276)

name-

re-

I

Taking

0111

~~'

ID

Crlnkcase

oJ,

(0.43i

r

measurements

gaske,ed

1

2

3

surfKe

on

cylinder sleeves

.:)

'.

Positions for checking sleeve bore diameter

(NOTE]

a)

All cylinders should be rebored the same oversize.

b) When the sleeves are not worn beyond the

but

repair limit, renewed, correct stepped wear on the top part

of

the sleeve by using a ridge reamer and, if necessary, refinish the sleeves by honing.

the piston rings have to be

to

one and

-20

Removing ridge

-

with

ridge reamer

(4) When the sleeves are worn beyond the service limit,

or when any cylinder bore the sleeve should be replaced with a new one.

When the inside surfaces bores in the crankcase are found it

is

necessary In this case, new ones. To replace, proceed

(a) Removal

to

too,

the liners should be replaced with

e Fix a boring machine

with the cylinder bore from which a sleeve removed. Aligning should be made at the part

of

the liner where

occurred.

• Bore the sleeve until it reaches 0.5 mm (0.0197 in.)

in stock thickness.

• Break the sleeve, exercising care not to damage the inside surface

(b) Installation

It

Visually check the inside surfaces bores for condition. bores

if

e When

bores, proceed

• Measure. the diameter outside diameter that the clearance between the sleeve and the bore is

0.08 mm (0.0031 in.) to 0.145 mm (0.0057 in.).

Heat the crankcase

Press the sleeve into the bores using a hydraulic press in such a manner to make the top to 0.020 in.) from the crankcase. Then, finish them to

be

flush with the crankcase. After pressing the sleeves, rebore and hone them to th

t

em a 0

of

the cylinder bore.

they are damaged.

it

is

unnecessary

as

in steps below.

of

sleeve protrude by 0.3 to 0.5 mm (0.012

84

+0.035

is

found to be defective,

of

one

of

more cylinder

to

be defective,

refinish the bores

as

to

the crankcase in alignment

less

abnormal wear has

It

is

necessary

to

reb ore the cylinder

of

cylinder bore and the

sleeve. Select oversize sleeve

to

about 300°C (572°F).

in

(3307

mm.

+0.0014. )

by

boring.

follows:

is

bottom

of

the cylinder

to

rebore the

the crankcase by

0

tn

..

to be

so

Pressing sleeve

• When

Cylinder sleeve

Standard

0.5 -oversize

Part

30607-50301

30607-50401

it

is necessary press the sleeves into position proceed

Prepare 0.5 sleeves.

Rebore the cylinder bores so

between the sleeve and the bore

(0.0031 in.)

After pressing the sleeves, rebore and hone them to th

When replacing the sleeves, use the sleeves following part numbers.

as

follows:

t 84 +0.035

em a 0

No.

mm

to

87+0.10

(3 425 +0.0004)

. +0.0028 875+

. +0.07

(3445

. +0.0028

to

rebore the cylinder bores,

as

in

b above, and

(0.0197 in.) oversize cylinder

that

the clearance

is

0.08 mm

0.145 mm (0.0057 in.).

(3307

mm.

Specifications

boring dimension

87

-0.010

-0.045 0

875-

.

-0.045

Specifications

0.0.

+0.07

10

0

.

+0.0004)

+0.0014. )

0 m

Unit·

Sleeve

(3 425

.

010

.

(3

445

.

1.0. Remarks

83.5

-0.2

83.5

0 0

-0.2

(3.287_

0

(3.287

-0.008)

-0.0004)

-0.0018

-0.0004)

-0.0018

Unit:

0

.

008

0

..

mm

(in )

of

the

mm (in.)

Standard

)

Oversize

-21-

Pistons and piston rings

(1) Pistons

Inspect each piston for any abnormal wear sliding surface, for cracks at the crown and for evidence grooves for stepped wear and sloped wear. Replace pistons found in bad condition.

of

melting or fusion. Examine the ring

of

its

(2) Measure the outside diameter

tions perpendicular to each other. exceeds the service limit, replace the piston.

Item

Standard

of

Specifications

0.25 (0.0098)

Diameter (at

skirt)

oversize

0.50 (0.0197)

oversize

0.75 (0.0295)

oversize

piston in two direc-

If

the diameter

Unit:

Standard

83.90 (3.3031)

84.15 (3.3130)

84.40

(3.3228)

84.65 (3.3327)

mm

(in.)

Service

limit

-0.2

(-0.008)

-22-

(3)

Replacing pistons Replace the piston with a new one ment exceeds

to

have

the pistons recommended

on

a piston selected linder for convenience. When the cylinder sleeves are bored pistons and piston rings

should be used. There are three oversizes for pistons and piston rings, namely, +0.50

mm The variance in weight among the pistons per engine should be

the

service limit. Where any pistons

be replaced, the variance in weight among

must

not

exceed the limit.

that

cylinder number be stamped

to

be used in a particular cy-

of

+0.25

(0.01969 in.) and 0.75

±5

grams (±0.18 oz), max.

if

the measure-

to

the

the same oversize

mm

(0.00984

mm

(0.0295 in.).

It

oversize,

in.),

Front

of

engine

t

is

Pilton

_ight

Piston weight marking

(4) Piston

(5) Piston ring

riD&

Check placing pushing

Insert the thicknesses

side clearance

gauge@.

the

gaps

ring gap

ring

in

pistOll true

Piston ring gap

grooves

compreuion

into

the

with

a straightedge and thickness

with

a thickness gauge

by

a new cylinder sleeve, and

and

square

in

the

bore.

Specifications

Item

and oil rings

grooves, and measure the

of

known

Piston

ring

Checking piston ring gap

Standard

0.30

(0.0118 ~ 0.0197)

~0.50

Gap

Unit: mm (in.)

Service

limit

1.5

(0.059)

Fit

in ring

grooves

Item

No.1

compression

ring No.2

compression ring

Oil

ring

Specifications

(0.00197 ~ 0.00335

(0.00098 ~ 0.00236)

-23

-

Measuring piston ring groove

Standard

0.050

~ 0.085

0.025 ~ 0.060

Unit·

mm

(in

Repair limit

0.20

(0.0079)

0.15

(0.0059)

)

(6)

Replacing piston riDp If

the rings are replaced, the gap width will exceed the standard value, concern, provided that the service limit exceeded.

but

this

is

not

a matter

(7) Piston pin bosses

the piston pin bosses

Check topic, Piston pins, piston pin bosses and piston pin bushings, which follows.

by

referring

is

to

of

not

the

Piston pins, piston pin bosses

and

piston pin

bushings

(1) Check the pin clearance

piston by computing the difference between the two

diameter readings, one taken the other in the boss. (clearance) exceeds the repair limit, replace piston pin with a new one.

Specifications

Item

Piston pin diameter

(2)

('heck the clearance fitted to the small end computing the difference between the two meter readings. If the computed difference (clearance) exceeds the repair limit, replace the pin or the bushing whichever

in

the pin boss

on

If

the computed difference

Standard

0

25

-0.006

(0.984_8.00024 )

of

the pin

of

is

in

the connecting rod by

badly worn.

of

the pin and

Unit: mm

Repair

limit

the bushing

dia·

the

(in)

Miking piston pin bushing and piston pin

Item

Piston pin boss

ID

Piston pin clearance in piston pin boss

Piston pin

bushingID

Piston pin clearance in piston pin bushing

Specifications

Standard

25

(0.984 -8.00024)

0-0.016

(0

- 0.00063)

25

·+0.045

(0.984

0.020 - 0.051 (0.00079 -

-8.006

+0.020 +0.00079

+0.00177

0.00201)

Unit· mm

Repair

limit

0.05

(0.0020)

)

0.08

(0.0031)

(in

)

-24-

Connecting rod alignment and bearings

(l)

Check the connecting rod for evidence

of

especially cracks in the fillets ends. Replace the rod if any cral:k fillets.

(2) Mount each connecting rod

aligner and check for bend and twist below. is must

(3)

If rod

(a) To check the rod for bend, measure

In

a twisted connecting rod, the bearing

not trued

the connecting rod aligner

may

"2"

ment at "c"

(0.00197 in. per 3.937 in.) the rod with the use

to

the small end bushing. Such a rod

be

corrected with the

be checked

as

shown in the

is

larger than 0.05 mm per 100 mm

as

follows:

figur~

of

a press.

its small and

is

in

the connecting rod

use

of

a press.

is

not available, the

"a."

If

of"

2," straighten

of

cracks,

big

noted

in

the

as

shown

"c" and

the measure-

f

t

a.

Checking the connect·

ing

rod for bend

Checking connecting rod

<0.05

100

b.

Checking the connect·

ing

rod for twist

(b) To check the rod for twist, measure

shown in the figure "C"

is

larger than 0.05 mm per 100 mm (0.00197 in. per 3.937 in.) rod.

"b."

If

the measurement at

of

"2,"

correct the

"c"

Checking connecting rod for bend

as

Checking connecting rod for twist

-25

-

(4)

To

~he.:k

the

surfa~e

round bar

the rod with a piston,

plate

as

shown below, insert a

of

the

~rankpin

pla~e

diameter into and

through its big end bore, and take measurement

at

"A"

and

"B."

The differen.:e between the two

measurements

When

one or more, or

be

repla~ed,

in

weight among the rods

given

in

tel1s

the straighteness

sele~t

new rods

the spedfication.

all

connecting rods are to

so

that the variance

is

within the value

Specification

Unit: gram (oz)

Variance

in

weight

among connecting rods

the rod on

of

the rod.

A

//

B

/

Checking connecting rod on surface plate

(5) Check the connecting rod end

playas

follows:

Check each connecting rod for end play in the manner illustrated, with the cap bolts tightened

to 5.5

kg-m

(39.8 lb-ft). measure the end play (which big end and crank arm).

Use

a thickness

is

the clearance between

If

the clearance measured

gauge

exceeds the service limit, replace the connecting

rod or bearing.

Specifications

Item

Connecting rod

end play

(6) Check the bearings

Standard

0.15 --0.35

(0.0059"" 0.0138)

as

follows:

(a) Inspect each bearing for evidence

Unit:

(0.0197)

of

wiping or

Service

fatigue failure, for scratches by dirt particles imbedded in and for improper seating

bore. Determine whether the bearing should

be re-used

or

replaced on the basis

of

fmdings.

(b) Check the radial clearance between crankpin

and bearing; is

exceeded the bearing. Where the crankpin to

the next undersize,

ing

of

that

if

the repair limit speCified below

by

the checked clearance, replace

is

to

use

a replacement bear-

undersize.

be ground

The two bearing undersizes are 0.25 mm (0.00984 in.) and 0.50 mm (0.01969 in.).

to

mm

limit

0.50

on

(in.)

the

Checking end

play of connecting rod

-26-