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This group covers cylinder head and valvetrain service and
repair. Some of the repair procedures described here require
that the cylinder head first be removed as described in
113
Cylinder Head Removal and Installation.
NOTE- For timing chain and
VANOS repair information, see 117
Camshaft Timing Chain.
If it is
determined that the cylinder head will require signif-
icant reconditioning work, a remanufactured cylinder head
may be a good alternative. Remanufactured cylinder
heads are available from an authorized
BMW dealer.
The information given in this repair group is organized ac-
cording to engine code. For engine application information,
see
I00 Engine-General.
For specific repair procedures, refer to the appropriate repair
group:
* 020 Maintenance
100 Engine-General
113 Cylinder Head Removal and Installation
117 Camshafi Timing Chain
= 170 Radiator and Coo!ing System
Special Tools
Special BMW tools are required for most cylinder head ser-
vice described in this repair group. Many of these tools are ex-
pensive and only available through an authorized
BMW
dealer. If the special tools are not available, have the cylinder
head removed and disassembled by an authorized BMW
dealer. Be sure to read each procedure thoroughly before
starting a job to determine which special tools and equipment
will be necessary.
Most of the repairs to a cylinder head require precision
rna-
chine work to specific tolerances. This type of work should be
performed by an authorized BMW repairfacility or an ASE
certified machinist.
71 Torque wrench with flex shaft
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Cylinder Head and Valvetrain
&cylinder models: remove plastic top
- Pry out caps (arrows).
- Remove fasteners and covers. covers:
4 V-8 models: remove plastic top
covers:
Press down on locking pins
(arrows) to release locks and
remove top cover.
Pry out caps
(A) from covers.
Remove fasteners and covers.
4 Lift metal latch on coil harness connectors and disconnect
harness connectors from coils. 6-cylinder shown,
V-8 similar.
- Remove coil grounding straps.
NOTE-
Make note of ground wire at mounting studs arrangement
during removal.
- -- -
-
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11 6-9
Cvlinder Head and valvetrain1
4 Remove ignition coils and spark plugs.
V-8 models: remove mounting nuts (arrows) from wiring har-
ness ducting.
< V-8 models: disconnect fuel injector electrical connectors
from injectors:
Pry one corner of wire
loclc clip (arrow) on first injector.
Repeat for all injectors.
Lift wire ducts off and set aside.
- V-8 models: disconnect battery jump start post terminal from
left cylinder head cover.
- 6-cylinder models: remove oil filler cap and unclip vent con-
nection from cylinder head cover.
- Remove cylinder head cover mounting fasteners and re-
move cylinder head cover(~).
NOTE-
The cylinder head cover mounting bolt insulators and gas-
Icets should be reinstalled in their original locations. Make
note of their arrangement
during removal.
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Cylinder Head and Valvetrain
< Remove oil baffle cover from above intake camshaft(s)
- Rotate engine at crankshaft vibration damper center bolt in
normal direction of rotation (clockwise) until camshaft lobe of
lifter to be tested points away from the lifter, allowing valve to
be completely closed.
Use a plastic or wooden stick to press down on top of lifter
with approximately 3.5 Nm
(2.25 ft-ib) of force.
If the lifter collapses slightly as though spring loaded, air
may be trapped in the lifter.
NOTE-
Air trapped in hydraulic lifters may result from oil foaming (air
being drawn
in by the oil pump). This may be caused by a
faulty oil pump control valve O-ring; leaking oil pump pickup
gaslcet; or by oil starvation to pump.
Press down on top of lifter for
10 to 15 seconds uslng approx-
lmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the
cam-
shafi lobe, the check valve in the lifter is not closing. Re-
place lifter.
- To replace a hydraulic lifter, remove appropriate camshaft.
Refer to camshaft removal procedures given in Camshaft
and lifter removal and installation.
Once camshaft is removed, withdraw faulty
lifter(s) and re-
place with new
lifter(s). Inspect lifter bores for wear and scor-
ing at arrows.
- Reinstall camshafts. See Camshaft and lifter removal and
installation.
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Cylinder Head and Valvetrain
4 Install intake camshaft oil baffle cover and cylinder head cov-
er:
= Checlc for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond 1209
@or equivalent
sealant at corners
(B) of half-moon cutouts and corners in
front of cylinder head at joint to timing chain cover.
Align cover at front and rear, then alternatively tighten fas-
teners from inside to outside.
Tightening torque
Sparic plug to cylinder head 25 Nm (18 it-lb)
Ignition coils to cylinder head 10 Nrn (7.5 ft-lb)
Cylinder head cover to cylinder iiead 10 Nrn (89 in-lb)
fM6 screws)
CAMSHAFT AND LIFTER REMOVAL
AND ~NSTALLATION
The camshafts can be removed with the cylinder heads
mounted on the engine (in the car).
On 6-cylinder engines there are two different procedures giv-
en, depending on whether the engine is equipped with single
VANOS (M52 engine) or double VANOS
(M52TU or M54 en-
gine).
For V-8 engines, camshaft removal and installation proce-
dures are
only included for the non-VANOS (M62) engine.
Camshaft removal and installation for the
VANOS eq;ipped
V-8 (M62TU) is not covered in this manual.
Special BMW service tools should always be used to remove
and install the camshafts. Removal of the camshafts without
the special tools can result in cylinder head damage and cam-
shaft breakage.
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116-12
I Cylinder Head and Valvetrain
Camshaft and lifter removal and installation
(M52 engine)
Camshafts and lifters, removing (M52 engine)
WARNING
-
The process of evenly loosening the camshaft bearing cap
nuts is NOT an acceptable method of removing the cam-
shafts. Special tools should always be used to remove the
camshafts. Be sure to read the procedure
tlirough before
starting a job.
I Allow engine to cool before beginning this procedure. /
- Disconnect negative (-) cable from battery.
CAUTION-
Prior to disconnecting the batfew read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove VANOS control unit from cylinder head. See 117
Camshaft Timing Chain.
I I 4 Remove loosened bolts (arrows) from front of exhaust
sprocket
nuts
(arrows) from intake camshaft
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116-15
Cylinder Head and Valvetrain
4 Remove primary timing chain tensioner plug (arrow) and pri-
mary tensioner.
CAUTION-
Primary timinq chain tensioner is under sarina aressure.
4 Remove primary timing chain sprocket and timing chain from
exhaust camshaft.
- Remove crankshaft locking tool (BMW 11 2 300) from
flywheel (installed during
VANOS removal).
Lift timing chain (holding under tension) and rotate engine
counterclockwise 30" from
TDC.
- Suspend timing chain with mechanic's wire
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Cylinder Head and valvetrain1
- Remainder of installation is reverse of removal, noting the
following:
See
117 Camshaft Timing Chain for VANOS control unit
installation.
Tightening torques
Camshaft bearing caps
to cylinder head (M7) 15 Nm (1 1 ft-lb)
Cylinder head cover to cylinder head (M6) 10 Nm (89 in-lb)
Sparic plugs (M12) 23 Nm (17 ft-lb)
Camshaft and lifter, removal and
installation
(M52 TU and M54 engine)
Camshafts and lifters, removing
(M52 TU and M54 engine)
WARNING-
Allow engine fo cool before beginning this procedure.
- Disconnect negative (-) cable from battery.
CAUTION--
Prior to disconnecting the battea read the battery discon-
nection cautions in
001 General Cautions and Warnings.
Remove VANOS control unit. See 117 Camshaii Timing
Chain.
Remove primary timing chain tensioner (arrow).
CAUTION-
Primary timing chain tensioner is under spring pressure. 1