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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.
Page 191 of 1002
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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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..--.
I Cylinder Head and Valvetrain - I
4 Lift primary chain and hold under tension, rotate engine
against direction of rotation (counterclockwise) approximate-
ly 30".
To prevent damaging valves while
worlcing on camshafts, no
aistons should be in the TDC position.
- Remove BMW special tool set 1 I 3 240 from rear of cylinder
head.
Remove retaining nuts (arrows) and bearing cap
1 of intake
camshaft.
Intake camshaft bearing cap
1 is centered with adapter
sleeves. To avoid camshaft damage, it must be removed be-
fore anv other caos.
4 Fit BMW special tools 11 3 260 (A) and 11 3 270 (B) to cylin-
der head and screw long bolts (aiiows) into spark plug
threads. Tensioners will align with the bearing caps on the in-
take camshaft.
CA UTION--
Do not over torque bolts into spark plug holes. 1
4 Turn eccentric shaft of special tool to pretension intake carn-
shaft bearing caps. Remove nuts on remaining bearing caps.
- Slowly release tension on eccentric shaft and remove BMW
special tools. Remove bearing caps and set aside in order.
Remove camshaft and store safely.
CA U TIOW-
Camshaft bearing caps must be installed in their original lo-
cations.
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~ ~. --
Cylinder Head and Valvetrain .-
4 While maintaining tension on timing chain, rotate crankshaft
at vibration dampener from
30" before TDC in direction of ro-
tation (clockwise) until number
1 cylinder is at TDC position
with line between the OIT mark (arrow) on front pulley
aligned with boss on lower timing chain cover.
4 Secure crankshaft in TDC position with BMW special tool
11 2 300 (arrow).
Slide impulse wheel on intake camshaft, aligning boss with
raised portion on camshaft (arrow).
Fit thrust spacer
(A) to intalte camshaft and tighten down with
threaded locating studs (arrows). Place longer threaded por-
tion of studs into camshaft.
Tightening torque
Impulse wheel studs to intake camshaft (M7)
20 Nm (15 ft-lb)
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11 6-42
/ Cvlinder Head and Valvetrain
4 Using crankshaft center bolt, rotate engine clockwise one
complete rotation until the first cylinder is at TDC.
4 Confirm TDC position. Lobes of camshafts for cylinder head
1-4 (passengers side) should point up (arrows).
4 Remove timing chain tensioner (arrow) from right side upper
timing chain cover.
- Remove secondary air injection pipes in front of upper timing
chain covers.
- Remove left and right coolant hoses from coolant pump
housing.
- Detach dipsticlc tube from upper right timing cover,
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..
ICylinder Head and Valvetrain -.I
4 Counterhold left intake camshaft and remove sprocket
mounting bolts
(arrows) from left cylinder head.
Remove primary chain sprocket.
Slide primary timing chain off sprocket and
supend timing
chain with stiff wire to prevent it from dropping into lower
timing chain cover.
4 Using cranltshaft center bolt, rotate engine counterclockwise
to
45" before TDC position. 45" V.OT mark on pulley will
align with boss cast on engine block
(arrow).
4 Compress secondary chain tensioners and lock (arrows)
using BMW special tool 11 3 310 or a stiff wire.
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ICylinder Head and Valvetrain -.
Rotate engine clockwise (arrow) from 45" before TDC to
TDC position.
Secure crankshaft in
TDC position with BMW special tool
11 2 300.
4 Fit sprocket with primary chain to intaite camshaft on right
cylinder head:
Press timing chain tensioner rail against timing chain
(white arrow) to check that fastener holes are centered in
sprocket slots (black arrows) when slack is removed from
timing chain.
If necessary, remove sprocket and reposition.
Fit sprocket with chain to intake camshaft
5-8 with long bores aligned centrally.
Install bolts (arrows) and finger tighten cylinder
head
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117-18
Camshaft Timing Chain
4 Loosen 4 bolts (arrows) from exhaust camshait sprocket
(Torx E10).
Press down on secondary chain tensioner and lock into place
using BMW special tool
11 3 292 or a similar size pin.
NOTE-
Two types of secondary timing chain tensioners are used;
one with two holes, and one with a single hole for the
locl
pin tool.
Remove VANOS control unit mounting fasteners at front of
cylinder head.
4 Install sprocltet rotating tool (BMW special tool 11 5 490) on
exhaust camshaft.
- Rotate exhaust camshaft sprocket clockwise while sliding
VANOS control unit forward to remove from cylinder head.