The crankshaft runs in five main bearings.
Thrustwashers are fitted to the centre main
bearing (upper half) to control crankshaft
endfloat.
The connecting rods rotate on horizontally-
split bearing shells at their big-ends. The
pistons are attached to the connecting rods
by gudgeon pins which are an interference fit
in the connecting rod small-end eyes. The
aluminium alloy pistons are fitted with three
piston rings, comprising two compression
rings and an oil control ring.
The cylinder bores are formed by
replaceable wet liners which are located from
their top ends. Two sealing rings are fitted at
the base of each liner to prevent the escape of
coolant into the sump.
The inlet and exhaust valves are each
closed by coil springs and operate in guides
pressed into the cylinder head. The valve seat
inserts are pressed into the cylinder head and
can be renewed separately if worn.
On the K8 engine, the camshaft is driven by
a toothed timing belt and operates the eight
valves via self-adjusting hydraulic tappets,
thus eliminating the need for routine checking
and adjustment of the valve clearances. The
camshaft rotates in six bearings that are line-
bored direct in the cylinder head and the
(bolted-on) bearing caps. This means that the
bearing caps are not available separately from
the cylinder head and must not be
interchanged with others from another engine.
The distributor is driven from the left-hand
end of the camshaft and the mechanical fuel
pump is operated by an eccentric on the
camshaft.
Apart from the fact that it has two
camshafts, one inlet and one exhaust, each
controlling eight valves and both retained by a
single camshaft carrier, the same applies to
the K16 engine. On the K16 engine, the
distributor is driven from the left-hand end of
the inlet camshaft. The fuel pump is
electrically-operated.
On both engine types, the coolant pump is
driven by the timing belt.
Lubrication is by means of an eccentric-
rotor trochoidal pump mounted on the
crankshaft right-hand end. It draws oil
through a strainer located in the sump and
then forces it through an externally-mounted
full-flow cartridge-type filter into galleries in
the oil rail and cylinder block/crankcase, from
where it is distributed to the crankshaft
(main bearings) and camshaft(s). The big-end
bearings are supplied with oil via internal
drillings in the crankshaft, while the camshaft
bearings and the hydraulic tappets receive a
pressurised supply. The camshaft lobes and
valves are lubricated by splash, as are all
other engine components.
Repair operations possible with
the engine in the car
The following work can be carried out with the
engine in the vehicle:
a) Compression pressure - testing.
b) Cylinder head cover - removal and
refitting.
c) Crankshaft pulley - removal and refitting.
d) Timing belt covers - removal and refitting.
e) Timing belt - removal, refitting and
adjustment.
f) Timing belt tensioner and sprockets -
removal and refitting.
g) Camshaft oil seal(s) - renewal.
h) Camshaft(s) and hydraulic tappets -
removal, inspection and refitting.
i) Cylinder head - removal and refitting.
j) Cylinder head and pistons -
decarbonising.
k) Sump - removal and refitting.
l) Oil pump - removal, overhaul and refitting.
m) Crankshaft oil seals - renewal.
n) Engine/transmission mountings -
inspection and renewal.
o) Flywheel - removal, inspection and
refitting.
Precautions
Note that a side-effect of the above
described engine design is that the crankshaft
cannot be rotated once the cylinder head and
block through-bolts have been slackened.
During any servicing or overhaul work the
crankshaft always must be rotated to the
desired position before the bolts are
disturbed.
2 Engine oil and filter - renewal
1 Details of checking the engine oil levels and
renewing both the oil and filter are contained
in “Weekly Checks” and Chapter 1.
3 Compression test -
description and interpretation
2
1 When engine performance is down, or if
misfiring occurs which cannot be attributed to
the ignition or fuel systems, a compression
test can provide diagnostic clues as to the
engine’s condition. If the test is performed
regularly it can give warning of trouble before
any other symptoms become apparent.
2 The engine must be fully warmed up to
normal operating temperature, the battery
must be fully charged and the spark plugs
must be removed. The aid of an assistant will
be required.
3 Disable the ignition system by
disconnecting the ignition HT coil lead from
the distributor cap and earthing it on the
cylinder block. Use a jumper lead or similar
wire to make a good connection.
4 Fit a compression tester to the No 1
cylinder spark plug hole. The type of tester
which screws into the plug thread is preferred
(see illustration).
5 Have the assistant hold the throttle wide
open and crank the engine on the starter
motor. After one or two revolutions, the
compression pressure should build up to a
maximum figure and then stabilise. Record
the highest reading obtained.
6 Repeat the test on the remaining cylinders,
recording the pressure in each.
7 All cylinders should produce very similar
pressures. Any difference greater than that
specified indicates the existence of a fault.
Note that the compression should build up
quickly in a healthy engine. Low compression
on the first stroke, followed by gradually
increasing pressure on successive strokes,
indicates worn piston rings. A low
compression reading on the first stroke, which
does not build up during successive strokes,
indicates leaking valves or a blown head
gasket (a cracked head could also be the
cause). Deposits on the undersides of
the valve heads can also cause low
compression.
8 If the pressure in any cylinder is reduced to
the specified minimum or less, carry out the
following test to isolate the cause. Introduce a
teaspoonful of clean oil into that cylinder
through its spark plug hole and repeat the
test.
9 If the addition of oil temporarily improves
the compression pressure, this indicates that
bore or piston wear is responsible for the
pressure loss. No improvement suggests that
leaking or burnt valves, or a blown head
gasket, may be to blame.
10 A low reading from two adjacent cylinders
is almost certainly due to the head gasket
having blown between them and the presence
of coolant in the engine oil will confirm this.
11 If one cylinder is about 20 percent lower
than the others and the engine has a slightly
rough idle, a worn camshaft lobe could be the
cause.
12 If the compression reading is unusually
high, the combustion chambers are probably
coated with carbon deposits. If this is the
case, the cylinder head should be removed
and decarbonised.
13 On completion of the test, refit the spark
plugs and reconnect the ignition system.
Engine in-car repair procedures 2A•5
3.4 Measuring compression pressure
2A
1689 Rover 214 & 414 Updated Version 09/97