1989 BMW 3 SERIES ECU

applied. Tighten the retaining nut to the
specified torque to hold the tensioner in its
correct position. Note:It is important that the
timing belt is tensioned correctly. If the belt is
over-tightened, it will howl, and there is the
possibility of it being damaged. If the belt is
too slack, it may jump on the sprockets.
24Check to make sure the camshaft and
crankshaft timing marks are still aligned(see
illustrations 10.5a and 10.5b).
25Turn the crankshaft clockwise through
two complete revolutions. (Remove the
camshaft positioning tool from the M40
engine first.)
Caution: This is necessary to
stretch the new belt. If not done,
the belt tensioner will be too
loose, and damage could result.
26On the M20 engine, loosen the tensioner
roller bolts, then tighten them to the torque
listed in this Chapter’s Specifications.
27On the M40 engine, loosen the tensioner
roller retaining nut, and re-adjust the tension
of the timing belt as described in paragraph
23. On completion, tighten the tensioner roller
retaining nut, then fully tighten the camshaft
sprocket bolt if previously loosened (see
illustration).
28Verify that the timing marks are still
perfectly aligned. If not, remove and refit the
timing belt.
29The remainder of refitting is the reverse of
removal.
11 Front oil seals- renewal
5
Note:Oil seals are fitted with their sealing lips
facing inwards (towards the engine).
M10 and M30 (timing chain)
engines
Camshaft front seal (M30 engines
only)
1Remove the upper timing chain cover only
(see Section 7).2Support the cover on two blocks of wood,
and drive out the seal from behind with a
hammer and screwdriver. Be very careful not
to damage the seal bore in the process.
3Coat the outside diameter and lip of the
new seal with multi-purpose grease, and drive
the seal into the cover with a hammer and a
socket slightly smaller in diameter than the
outside diameter of the seal.
4The remainder of refitting is the reverse of
removal.
Crankshaft front seal (M10 and
M30 engines)
5Remove the crankshaft pulley and vibration
damper (see Section 7).
6Carefully prise the old seal out of the cover
with a large screwdriver. Be very careful not to
damage the seal bore or the crankshaft with
the tool. Wrap the tip of the screwdriver with a
piece of tape to prevent damage.
7Clean the bore in the cover, and coat the
outer edge of the new seal with engine oil or
multi-purpose grease. Also lubricate the lips
of the seal with multi-purpose grease. Using a
socket with an outside diameter slightly
smaller than the outside diameter of the seal,
carefully drive the new seal into place with a
hammer (see illustration). If a socket isn’t
available, a short section of large-diameter
pipe will work. Check the seal after refitting to
be sure the spring around the inside of the
seal lip didn’t pop out of place.
8The remainder of refitting is the reverse of
removal.
M20 and M40 (timing belt)
engines
Camshaft front seal (M20 and
M40 engines)
9Remove the timing belt and camshaft
sprocket (see Section 10).
10On the M20 engine only, remove the two
screws, and separate the camshaft seal
housing from the cylinder head by pulling it as
you rotate it back and forth.
11On the M20 engine only, support the
housing on two blocks of wood, and drive the
seal out of the housing from behind using ahammer and screwdriver. Be very careful not
to damage the seal housing.
12On the M40 engine, prise the seal out
from the cylinder head using a screwdriver,
being careful not to damage the camshaft
surface or the seal bore.
13Coat the lip and outside diameter of the
new seal with multi-purpose grease.
14On the M40 engine, wrap some adhesive
tape around the end of the camshaft to
protect the new seal from the location groove
as it is being fitted (see illustration).
15Carefully locate the new seal in position,
and press it in by hand initially so that it enters
the bore. Drive the new seal into the housing
or cylinder head (as applicable) using a
hammer and a socket with a diameter slightly
smaller than the outside diameter of the seal.
On the M40 engine, remove the adhesive tape
from the end of the camshaft.
16On the M20 engine, renew the O-ring on
the back of the seal housing, and work the lip
of the seal over the end of the camshaft. Refit
the screws and tighten them securely.
17The remainder of refitting is the reverse of
removal.
Crankshaft and intermediate shaft
front seals (M20 engines)
18Remove the timing belt and crankshaft
and intermediate shaft pulleys as applicable
(see Section 10). Note:We recommend the
timing belt be renewed any time it is removed.
19Remove the bolts and nuts securing the
front cover to the engine block. Be sure to
remove the three bolts from underneath that
connect the front of the sump to the bottom of
the front cover (see illustration 7.14).
20Run a sharp, thin knife between the sump
gasket and the front cover, cutting the cover
free from the gasket. Be very careful not to
damage the gasket, and keep it clean so you
can re-use it.
21Break the front cover-to-block gasket seal
by tapping the cover with a rubber mallet or
block of wood and hammer. Do not prise
between the cover and the engine block, as
damage to the gasket sealing surfaces will
result.
2A•12 In-car engine repair procedures
11.14 Fitting a new camshaft oil seal on
the M40 engine (note the adhesive tape
around the end of the camshaft to protect
the seal)11.7 The crankshaft front oil seal is
pressed into the front of the lower timing
chain cover (cover removed from the
engine for clarity)10.27 Tightening the camshaft sprocket
retaining bolt on the M40 engine

13 Sump- removal and refitting
1
1Drain the engine oil (see Chapter 1).
2Raise the front of the vehicle and place it
securely on axle stands.
3Remove the splash shields from under the
engine.
4Where applicable, disconnect the hoses
attached to the sump, and move them to one
side (see illustration).
5Where applicable, disconnect the oil level
sensor electrical connector (see illustration).
6Where applicable, remove the cast-
aluminium inspection cover that covers the
rear of the sump (see illustrations).
7On models with the M40 engine, unbolt and
remove the lower sump section and remove
the gasket (this is necessary for access to the
front mounting bolts). Unscrew the mounting
bolt, and pull the oil dipstick tube from the
sump (see illustrations). Check the condition
of the O-ring, and renew it if necessary.
8On models with the M40 engine, unscrew
the engine mounting nuts on both sides, then
attach a suitable hoist and lift the engine
sufficiently to allow the sump to be removed.
As a safety precaution, position axle stands or
blocks of wood beneath the engine.
9Remove the bolts securing the sump to theengine block and front/rear covers (see
illustration).
10Tap on the sump with a soft-faced
hammer to break the gasket seal, and lower
the sump from the engine.
11Using a gasket scraper, scrape off all
traces of the old gasket from the engine
block, the timing chain cover, the rear main oil
seal housing, and the sump. Be especially
careful not to nick or gouge the gasket sealing
surfaces of the timing chain cover and the oil
seal housing (they are made of aluminium,
and are quite soft).
12Clean the sump with solvent, and dry it
thoroughly. Check the gasket sealing surfaces
for distortion. Clean any residue from thegasket sealing surfaces on the sump and
engine with a rag dampened with a suitable
solvent.
13Before refitting the sump, apply a little
RTV-type gasket sealant to the area where the
front and rear covers join the cylinder block..
Lay a new sump gasket in place on the block.
If necessary, apply more sealant to hold the
gasket in place.
14Carefully position the sump in place (do
not disturb the gasket) and refit the bolts.
Start with the bolts closest to the centre of the
sump, and tighten them to the torque listed in
this Chapter’s Specifications, using a criss-
cross pattern. Do not overtighten them, or
leakage may occur.
In-car engine repair procedures 2A•15
13.5 If applicable, disconnect the oil level
sensor connector at the left side of the
engine, down near the power steering
pump mounting bracket13.4 If applicable, remove the nut securing
the power steering lines to the sump, and
move the lines to one side to allow you to
get at the sump bolts12.30e Angle-tightening the cylinder head
bolts (M40 engine)
13.9 Remove the bolts holding the sump
to the engine block and front cover, as
shown here on a six-cylinder engine13.7b Removing the oil dipstick tube
bracket mounting bolt
13.6b . . . remove the cover to get to all
the sump bolts13.6a Remove the four inspection cover
bolts (arrowed) and . . .
13.7a Main sump retaining bolts accessed
after removal of the lower sump section on
the M40 engine (engine on bench for clarity)
2A

Inspection
Note:Considering that a malfunctioning oil
pump can easily cause major engine damage,
we recommend that the oil pump should
always be renewed during engine overhaul,
unless it’s in as-new condition.
M10, M20 and M30 engines
16Remove the cover and check the pump
body, gears or rotors and cover for cracks
and wear (especially in the gear or rotor
contact areas).
17Check the strainer to make sure it is not
clogged or damaged.
18Lubricate the gears with clean engine oil,
then attach the pump cover to the body and
tighten the bolts evenly and securely.19Before refitting the pump - new, rebuilt or
original - on the engine, check it for proper
operation. Fill a clean container to a depth of
one inch with fresh engine oil of the
recommended viscosity.
20Immerse the oil pump inlet in the oil, and
turn the driveshaft anti-clockwise by hand. As
the shaft is turned, oil should be discharged
from the pump outlet.M40 engines
21With the front end cover on the bench,
unscrew the bolts and remove the cover plate
to expose the oil pump rotors (see
illustrations).
22Identify the rotors for position, then
remove them from the housing (see
illustrations).23Clean the housing and the rotors
thoroughly, then refit the rotors, making sure
that they are in their previously-noted
positions. The inner rotor must be fitted with
the guide facing the body.
24Using feeler blades, measure the
clearance between the oil pump body and the
outer rotor, then check the clearance
between the outer and inner rotors (see
illustrations).
25If the clearance is not as given in the
Specifications, the complete oil pump and
front end cover should be renewed. If the
clearance is within tolerance, remove the
rotors, then pour a little engine oil into the
housing. Refit the rotors and turn them to
spread the oil around.
In-car engine repair procedures 2A•17
14.14a Front end cover and oil pump in
position on the front of the M40 engine14.13 Removing the spacer ring from the
front of the crankshaft14.12 Removing the key from the groove
in the nose of the crankshaft (M40 engine)
14.24a Measuring the clearance between
the oil pump body and the outer rotor
(M40 engine)14.22b . . . and outer rotor from the oil
pump (M40 engine)14.22a Removing the inner rotor . . .
14.21b . . . and remove the oil pump cover
(M40 engine)14.21a Unscrew the bolts . . .14.14b Extract the rubber O-ring from the
groove in the nose of the crankshaft
(M40 engine)
2A

the crankshaft flange (see illustration). Be
careful - the flywheel is heavy.
5To refit the flywheel/driveplate on the
crankshaft, use a liquid thread-locking
compound on the bolts, and tighten them
gradually, using a criss-cross pattern, to the
torque listed in this Chapter’s Specifications.
6The remainder of refitting is the reverse of
removal.
16 Crankshaft rear oil seal-
renewal
3
1Remove the flywheel or driveplate (see
Section 15).
2Remove the bolts and/or nuts attaching the
seal retainer to the engine block. Be sure to
remove the two bolts (from underneath)
connecting the rear of the sump to the bottom
of the seal retainer (see illustration).
3Run a sharp, thin knife between the sump
gasket and the seal retainer, cutting the
retainer free from the gasket. Be very careful
not to damage the gasket, and keep it clean
so you can re-use it.
4Break the seal retainer-to-block gasket seal
by tapping the retainer with a plastic mallet or
block of wood and hammer. Do not prise
between the retainer and the engine block, as
damage to the gasket sealing surfaces will
result.
5Using a scraper, remove all traces of old
gasket material from the sealing surfaces of
the retainer and engine block. Gasket removal
solvents are available at car accessory shops,
and may prove helpful. After all gasket
material has been removed, the gasket
surfaces can be degreased by wiping them
with a rag dampened with a suitable solvent.
Caution: Be very careful not to
scratch or gouge the delicate
aluminium surfaces. Also, do not
damage the sump gasket, and
keep it clean.
6Support the retainer on two blocks of
wood, and drive out the seal from behind with
a hammer and screwdriver (see illustration).Be very careful not to damage the seal bore in
the process.
7Coat the outside diameter and lip of the
new seal with multi-purpose grease, and drive
the seal into the retainer with a hammer and a
block of wood (see illustration).
8Apply a film of RTV-type gasket sealant to
the surface of the sump gasket that mates with
the seal retainer. Apply extra beads of RTV
sealant to the edges where the gasket meets
the engine block. Note:If the sump gasket is
damaged, instead of fitting a whole new
gasket, you might try trimming the rear portion
of the gasket off at the point where it meets the
engine block, then trim off the rear portion of a
new sump gasket so it’s exactly the same size.
Cover the exposed inside area of the sump
with a rag, then clean all traces of old gasket
material off the area where the gasket was
removed. Attach the new gasket piece to the
sump with contact-cement-type gasket
adhesive, then apply RTV-type sealant as
described at the beginning of this paragraph.
9Coat both sides of the new retainer gasket
with RTV-type gasket sealant, then attach the
gasket to the seal retainer. Fit the seal retainer
to the rear of the engine, then refit the bolts
and tighten them evenly to the torque listed in
this Chapter’s Specifications. Work from bolt-
to-bolt in a criss-cross pattern to be sure
they’re tightened evenly.Note 1:Tighten the
retainer-to-block bolts first, then tighten the
sump-to-retainer bolts.Note 2:After applying
RTV-type sealant, reassembly must becompleted in about 10 minutes so the RTV
won’t prematurely harden.
10Refit the flywheel/driveplate (see Sec-
tion 15).
11Refit the transmission (on vehicles with
manual transmission, see Chapter 7A; on
vehicles with automatic transmission, see
Chapter 7B).
17 Engine mountings-
check and renewal
1
1Engine mountings seldom require attention,
but broken or deteriorated mountings should
be renewed immediately, or the added strain
placed on the driveline components may
cause damage or wear.
Check
2During the check, the engine must be
raised slightly to remove its weight from the
mounts.
3Raise the vehicle and support it securely on
axle stands, then position a jack under the
engine sump. Place a large block of wood
between the jack head and the sump, then
carefully raise the engine just enough to take
its weight off the mounts.
Warning: DO NOT place any part
of your body under the engine
when it’s supported only by a
jack!
In-car engine repair procedures 2A•19
16.6 After removing the retainer from the
block, support it on two wood blocks, and
drive out the old seal with a punch and
hammer16.2 Remove the six bolts from the rear of
the block and the two from underneath at
the sump15.4 Using a socket and ratchet, remove
the eight bolts that hold the flywheel/
driveplate to the crankshaft flange - prevent
the flywheel/driveplate from turning by
locking the ring gear with a lever
17.4 As engine mountings wear or age,
they should be inspected for cracking or
separation from their metal plates
16.7 Drive the new seal into the retainer
with a block of wood, or a section of pipe,
if you have one large enough - make sure
the seal enters the retainer bore squarely
2A

4Check the mountings to see if the rubber is
cracked (see illustration), hardened or
separated from the metal plates. Sometimes
the rubber will split right down the centre.
5Check for relative movement between the
mounting plates and the engine or frame (use
a large screwdriver or lever to attempt to
move the mountings). If movement is noted,
lower the engine and tighten the mounting
nuts or bolts (see illustration). Rubber
preservative should be applied to the
mountings, to slow deterioration.
6On models with the M40 engine, check the
condition of the dampers on each mounting
by disconnecting them and attempting tocompress and expand them (see illustration).
If there is very little resistance to movement,
the dampers should be renewed.
Renewal
7If the dampers on the M40 engine are to be
renewed, simply unscrew the bolts, then fit
the new dampers and tighten the bolts.
8To renew the mountings, disconnect the
battery negative cable, then raise the vehicle
and support it securely on axle stands if you
haven’t already done so.
Caution: If the radio in your
vehicle is equipped with an anti-
theft system, make sure you
have the correct activation codebefore disconnecting the battery.
Note: If, after connecting the battery, the
wrong language appears on the instrument
panel display, refer to page 0-7 for the
language resetting procedure.
9Support the engine as described in
paragraph 3.
10Remove the large bracket-to-mounting
nut (see illustration). Raise the engine
slightly, then remove the lower mounting-to-
frame bolts/nuts and detach the mounting
11Refitting of the mountings is the reverse of
removal. Use thread-locking compound on
the mounting bolts/nuts, and be sure to
tighten them securely.
2A•20 In-car engine repair procedures
17.10 To remove an engine mounting, first
remove the stud nut (arrowed) -
M30 engine shown, others similar17.6 Engine mounting and damper on the
M40 engine17.5 Lever gently between the block and
the engine mounting attachment point
(arrowed) - if there is movement, tighten
the bolts

detach them. Pieces of masking tape with
numbers or letters written on them work well
(see illustration).
6Label and detach all coolant hoses from the
engine (see Chapter 3).
7Remove the cooling fan, shroud and
radiator (see Chapter 3). Note:On the M40
engine, it is only necessary to remove the
cooling fan and shroud; however, prevent
damage to the radiator by covering it with a
piece of wood or cardboard.
8Remove the drivebelts (see Chapter 1).
9Disconnect the fuel lines from the fuel rail
(see Chapter 4).
Warning: Fuel is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area, and don’t work
in a garage where a natural gas-type
appliance (such as a water heater or
clothes dryer) with a pilot light is present.
If you spill any fuel on your skin, rinse it off
immediately with soap and water. When
you perform any kind of work on the fuel
system, wear safety glasses, and have a
fire extinguisher on hand.
10Disconnect the accelerator cable (see
Chapter 4) and kickdown linkage/speed
control cable (see Chapter 7B), if applicable,
from the engine.
11Where fitted, unbolt the power steering
pump (see Chapter 10). Leave the lines/hoses
attached, and make sure the pump is kept in
an upright position in the engine compartment
(use wire or rope to restrain it out of the way).
12On air-conditioned models, unbolt the
compressor (see Chapter 3) and set it aside,
or tie it up out of the way. Do not disconnect
the hoses.
13Drain the engine oil (see Chapter 1) and
remove the filter. Remove the engine splash
guard from under the engine.
14Remove the starter motor (see Chapter 5).15Remove the alternator (see Chapter 5).
This is not essential on all models, but it is a
good idea in any case to avoid accidental
damage.
16Unbolt the exhaust system from the
engine (see Chapter 4).
17If you’re working on a vehicle with an
automatic transmission, remove the torque
converter-to-driveplate fasteners (see
Chapter 7B). On the M40 engine, unbolt the
automatic transmission fluid coolant pipes
from the sump.
18Support the transmission with a jack.
Position a block of wood between them, to
prevent damage to the transmission. Special
transmission jacks with safety chains are
available - use one if possible.
19Attach an engine sling or a length of chain
to the lifting brackets on the engine. If the
brackets have been removed, the chain can
be bolted directly to the intake manifold studs,
but place a flat washer between the chain and
the nut, and tighten the nut all the way up to
the chain, to avoid the possibility of the studs
bending.
20Roll the hoist into position and connect
the sling to it. Take up the slack in the sling or
chain, but don’t lift the engine.
Warning: DO NOT place any part
of your body under the engine
when it’s supported only by a
hoist or other lifting device.
21On M10, M20 and M30 engines, remove
the transmission rear crossmember, and
slightly lower the rear of the transmission.
22Remove the transmission-to-engine block
bolts using a Torx socket. Note:The bolts
holding the bellhousing to the engine block
will require a swivel at the socket, and a very
long extension going back towards the
transmission.
23Remove the engine mounting-to-frame
bracket nuts. On the M40 engine, unbolt the
dampers from the mountings.
24Recheck to be sure nothing is still
connecting the engine to the transmission or
vehicle. Disconnect anything still remaining.
25Raise the engine slightly. Carefully work it
forwards to separate it from the transmission.
If you’re working on a vehicle with an
automatic transmission, you may find the
torque converter comes forward with theengine. If it stays with the transmission, leave
it, but you may find it easier to let it come
forward until it can be grasped easier and be
pulled from the crankshaft. Note:When
refitting the torque converter to the
transmission before the engine is refitted, be
sure to renew the transmission front pump
seal, which will probably be damaged when
the converter comes out with the engine.
Either method is acceptable, but be prepared
for some fluid to leak from the torque
converter if it comes out of the transmission. If
you’re working on a vehicle with a manual
transmission, draw the engine forwards until
the input shaft is completely disengaged from
the clutch. Slowly raise the engine out of the
engine compartment. Check carefully to make
sure everything is disconnected.
26Remove the flywheel/driveplate (and
where applicable, the engine rear plate), and
mount the engine on an engine stand (see
illustration). Do not turn the M40 engine
upside-down (see Cautionin Section 4).
Refitting
27Check the engine and transmission
mountings. If they’re worn or damaged, renew
them.
28Refit the flywheel or driveplate (see
Chapter 2A). If you’re working on a manual
transmission vehicle, refit the clutch and
pressure plate (see Chapter 7A). Now is a
good time to fit a new clutch.
29If the torque converter came out with the
engine during removal, carefully refit the
converter into the transmission before the
engine is lowered into the vehicle.
30Carefully lower the engine into the engine
compartment - make sure the engine
mountings line up.
31If you’re working on an automatic
transmission vehicle, guide the torque
converter onto the crankshaft following the
procedure outlined in Chapter 7B.
32If you’re working on a manual
transmission vehicle, apply a dab of high-
melting-point grease to the input shaft, and
guide it into the clutch and crankshaft pilot
bearing until the bellhousing is flush with the
engine block.. Do not allow the weight of the
engine to hang on the input shaft.
33Refit the transmission-to-engine bolts,
and tighten them securely.
Caution: DO NOT use the bolts to
force the transmission and
engine together.
34Refit the remaining components in the
reverse order of removal.
35Add coolant, oil, power steering and
transmission fluid as needed.
2B•6 General engine overhaul procedures
5.26 Removing the engine rear plate -
M40 engine5.5 Label each wire before unplugging the
connector
If there’s any possibility of
confusion, make a sketch of
the engine compartment and
clearly label the lines, hoses
and wires.
It may be necessary to rock
the engine slightly, or to turn
the crankshaft, to allow the
input shaft splines to mate
with the clutch plate

M10, M20 and M30 engines
3Adjust all valves to their maximum clearance
by rotating the eccentric on the valve end of
the rocker arm towards the centre of the head
(see Chapter 1, if necessary).
4Before removing the thrustplate, measure
the camshaft endfloat by mounting a dial
indicator to the front end of the cylinder head,
with the probe resting on the camshaft (see
illustration). Prise the camshaft back-and-
forth in the cylinder head. The reading is the
camshaft endfloat. Compare the reading to
this Chapter’s Specifications.
5Unbolt and remove the camshaft
thrustplate. Note:There are two different
locations for the thrustplate. On M10 and M30
engines, it is attached on the front of the
cylinder head, behind the timing gear flange.
On M20 and M40 engines, the thrustplate is
located inside the head, by the rocker shafts,
at the forward end of the cylinder head.
6Remove the rear cover plate from the back
of the cylinder head (see illustration).
7Remove the retaining clips from each of the
rocker arms. Note:There is more than one
style of clip. The wire-type clips (see
illustration)are fitted one each side of the
rocker arm; the spring-steel-type goes over
the rocker arm, and clips onto either side of it.
8Before removing the rocker arm shafts,
measure the rocker arm radial clearance,
using a dial indicator, and compare your
measurement to the Specifications at thebeginning of this Chapter. Without sliding the
rocker arm along the shaft, try to rotate the
rocker arm against the shaft in each direction
(see illustration). The total movement
measured at the camshaft end of the rocker
arm is the radial clearance. If the clearance is
excessive, either the rocker arm bush, rocker
arm shaft, or both, will need to be renewed.
9Remove the rubber retaining plugs, or the
threaded plugs, at the front of the cylinder
head, as applicable. There is a plug in front of
each rocker shaft.
Caution: If your engine has
welded-in retaining plugs at the
front of the rocker shafts, take
the cylinder head to a machine
shop for plug removal, to avoid possible
damage to the cylinder head or the rocker
arm shafts.
10Rotate the camshaft until the most rocker
arms possible are loose (not compressing
their associated valve springs).
11For the remaining rocker arms that are still
compressing their valve springs, BMW
recommends using a special forked tool to
compress the rocker arms against the valve
springs (and therefore take the valve spring
tension off the camshaft lobe). If the tool is not
available, insert a standard screwdriver into the
gap above the adjuster eccentric at the valve-
end tip of each rocker arm. Using thescrewdrivers, prise the rocker arms against the
valve springs, and hold them in place as the
camshaft is removed (see the next paragraph).
At least one assistant will be necessary for this
operation, since three or four valve springs
usually need compressing. If no assistance is
available, you could try retaining the
screwdrivers that are compressing the valve
springs to the bench with lengths of sturdy wire.
Warning: Be sure the wire is
securely attached to the bench
and screwdrivers, or the
screwdrivers could fly off the cylinder
head, possibly causing injury.
12When all the rocker arms are no longer
contacting the camshaft lobes, slowly and
carefully pull the camshaft out the front of the
cylinder head. It may be necessary to rotate
the camshaft as it is removed.
Caution: Be very careful not to
scratch the camshaft bearing
journals in the cylinder head as
the camshaft is withdrawn.
13After removing the camshaft, carefully
remove the rocker arm shafts. On models
without threaded holes at the front of the
shafts, drive them out from the rear of the
cylinder head with a hammer and hardwood
dowel that is slightly smaller in diameter than
the rocker arm shaft (see illustration). For
2B•8 General engine overhaul procedures
8.13 Removing a rocker arm shaft from
the front of the cylinder head - the shaft
must be either driven out from the rear of
the head with a hardwood dowel or, on
models where the rocker shaft is threaded
at the front, pulled out from the front with
a slide-hammer-type puller
8.8 Check the rocker arm-to-shaft radial
clearance by setting up a dial indicator as
shown, and trying to rotate the rocker arm
against the shaft - DO NOT slide the rocker
arm along the shaft
8.7 Remove the retaining clips from the
rocker arms - the wire-type clip is shown
here
8.6 Remove the cover from the rear of the
cylinder head - be sure to note the
locations of any washers, gaskets and
seals while you are removing the cover8.4 To check camshaft endfloat, mount a
dial indicator so that its stem is in-line with
the camshaft and just touching the
camshaft at the front8.2b Removing the oil tube from the
camshaft bearing caps on the top of the
cylinder head (M40 engine)

carbon deposits or cylinder wear have
produced ridges, they must be completely
removed with a special tool called a ridge
reamer (see illustration). Follow the
manufacturer’s instructions provided with the
tool. Failure to remove the ridges before
attempting to remove the piston/connecting
rod assemblies may result in piston ring
breakage.
2After the cylinder ridges have been
removed, turn the engine upside-down so the
crankshaft is facing up.
3Before the connecting rods are removed,
check the side play with feeler gauges. Slide
them between the first connecting rod and
crankshaft web until no play is apparent (see
illustration). The side play is equal to the
thickness of the feeler gauge(s). If the side
play exceeds the service limit, new
connecting rods will be required. If new rods
(or a new crankshaft) are fitted, ensure that
some side play is retained (if not, the rods will
have to be machined to restore it - consult a
machine shop for advice if necessary). Repeat
the procedure for the remaining connecting
rods.
4Check the connecting rods and caps for
identification marks. If they aren’t plainly
marked, use a small centre-punch to make
the appropriate number of indentations (see
illustration)on each rod and cap (1, 2, 3, etc.,
depending on the cylinder they’re associated
with).
5Loosen each of the connecting rod cap
nuts/bolts a half-turn at a time until they can
be removed by hand. Remove the No 1
connecting rod cap and bearing shell. Don’t
drop the bearing shell out of the cap.
6Where applicable, slip a short length of
plastic or rubber hose over each connecting
rod cap stud to protect the crankshaft journal
and cylinder wall as the piston is removed
(see illustration).
7Remove the bearing shell, and push the
connecting rod/piston assembly out through
the top of the engine. Use a wooden hammer
handle to push on the upper bearing surface
in the connecting rod. If resistance is felt,
double-check to make sure that all of the
ridge was removed from the cylinder.8Repeat the procedure for the remaining
cylinders.
9After removal, reassemble the connecting
rod caps and bearing shells in their respective
connecting rods, and refit the cap nuts/bolts
finger-tight. Leaving the old bearing shells in
place until reassembly will help prevent the
connecting big-end bearing surfaces from
being accidentally nicked or gouged.
10Don’t separate the pistons from the
connecting rods (see Section 18).
13 Crankshaft- removal
5
Note: The crankshaft can be removed only
after the engine has been removed from the
vehicle. It’s assumed that the flywheel or
driveplate, vibration damper, timing chain or
belt, sump, oil pump and piston/connecting
rod assemblies have already been removed.
The rear main oil seal housing must be
unbolted and separated from the block before
proceeding with crankshaft removal.
1Before the crankshaft is removed, check
the endfloat. Mount a dial indicator with the
stem in line with the crankshaft and touching
the nose of the crankshaft, or one of its webs
(see illustration).
2Push the crankshaft all the way to the rear,and zero the dial indicator. Next, prise the
crankshaft to the front as far as possible, and
check the reading on the dial indicator. The
distance that it moves is the endfloat. If it’s
greater than the maximum endfloat listed in
this Chapter’s Specifications, check the
crankshaft thrust surfaces for wear. If no wear
is evident, new main bearings should correct
the endfloat.
3If a dial indicator isn’t available, feeler
gauges can be used. Identify the main bearing
with the thrust flanges either side of it - this is
referred to as the “thrust” main bearing (see
Section 24, paragraph 6). Gently prise or push
the crankshaft all the way to the front of the
engine. Slip feeler gauges between the
crankshaft and the front face of the thrust
main bearing to determine the clearance.
4Check the main bearing caps to see if
they’re marked to indicate their locations.
They should be numbered consecutively from
the front of the engine to the rear. If they
aren’t, mark them with number-stamping dies
or a centre-punch (see illustration). Main
bearing caps generally have a cast-in arrow,
which points to the front of the engine.
Loosen the main bearing cap bolts a quarter-
turn at a time each, working from the outer
ends towards the centre, until they can be
removed by hand. Note if any stud bolts are
used, and make sure they’re returned to their
original locations when the crankshaft is
refitted.
General engine overhaul procedures 2B•13
12.4 Mark the big-end bearing caps in
order from the front of the engine to the
rear (one mark for the front cap, two for
the second one and so on)12.3 Check the connecting rod side play
with a feeler gauge as shown12.1 A ridge reamer is required to remove
the ridge from the top of each cylinder - do
this before removing the pistons!
13.1 Checking crankshaft endfloat with a
dial indicator
12.6 To prevent damage to the crankshaft
journals and cylinder walls, slip sections of
rubber or plastic hose over the rod bolts
before removing the pistons
2B