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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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. .
Cylinder Head and Valvetrain
Install exhaust camshaft impulse wheel, aligning pointer (B)
with top edge of cylinder head (A). Install mounting nuts (ar-
rows) finger tight.
4 Pull out exhaust camshaft splined shaft to stop.
- Press down on secondary chain tensioner and remove ten-
sioner lock-down tool.
Preload primary chain:
- Tighten adjusting screw on BMW special tool 11 4 220 to
specified torque.
Tightening torque Primary chain tensioner preload
0.7 Nm (6 in-lb)
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1 16-36
I Cylinder Head and Valvetrain
4 Preload exhaust camshaft spring plate by pressing on im-
pulse wheel while tightening mounting nuts (arrows)
fingel
tight.
4 Install BMW special tool 11 6 150 (VANOS setup bracket) to
front of cylinder head timing case. Install nuts (arrows) finger
tight, then tighten down uniformly until special tool is in full
contact with cylinder head.
CAUTION--
Male sure aNgas1ef material Is removed from face of cyiin-
der head. Clean sealing face and keep free of oil.
4 Secure camshaft sprockets and impulse wheels:
Tighten mounting screws (A) on exhaust camshaft impulse
wheel to approx.
5 Nm (44 in-lb).
Tighten mounting nuts (B) on exhaust and intake sprocket
assemblies to approx.
5 Nm (44 in-lb).
Torque down mounting screws (A) and nuts (B) to final
specifications.
Tightening torques Sprocket assembly to camshaft initial torque
5 Nm (44 in-lb)
Sprocket assembly wheel to carnshaft
M7 tom screws (A) 20 Nm (15 ft-lb)
M6 mounting sciew (6) I0 Nm (8 ft-lb) - - -
- - Remove crankshaft locking tool from crankcase.
- Remove camshaft locking tools from cylinder head.
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I Cylinder Head and Valvetrain
- Remove adjustable primary timing chain tensioner tool and
reinstall primary chain tensioner cylinder to cylinder head.
Tightening torque
Primary chain tensioner cylinder
to 70 Nm (52 ft-lb)
cylinder head
- Remove flywheel locking tool from crankcase. Replace spe-
cial tool bore sealing plug.
- Remove camshaft locking tools from cylinder head
Install intake camshaft cover and cylinder head cover.
Check for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond
8 1209 or equivalent
sealing compound at corners
(B) of half-moon cutouts.
Seat gasket and seal corners at VANOS unit with Three
Bond
@ 1209.
Tightening torque Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Installation of the remaininq parts is reverse or removal, not- -
ing the following:
Change engine
011 and f~lter as descr~bed in 020 Mainte-
nance.
Reconnect battery.
To prevent damaging the engine electronic systems, install
all ground wire previously removed, including the ground
wires for the ignition coils.
Tightening torque
-
Radiator cooling fan to coolant pump 40 Nm
(30 ft-ib)
Spark plug to cylinder head
25 Nm (18 ft-ib)
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Cylinder Head and valvetrain1
4 Remove camshaft position sensor (A) from timing chain cov-
er. Remove bolts
(arrows) from timing chain covers and re-
move covers from right and left cylinder heads.
4 Counterhold intalte carnshaft on right cylinder head
4 Counterhold right intalte camshaft and remove sprocltet
mounting bolts
(arrows) from right cylinder head.
Remove carnshaft impulse wheel and primary chain
sprocket.
- Slide primary timing chain off sprocltet and suspend chain
with stiff wire to prevent it from dropping into lower timing
chain cover.
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1 16-56
Cylinder Head and Valvetrain
This section covers valve removal and reconditioning, includ-
ing valve guides, seats, springs, and valve stem oil seals.
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes,
check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Valves, removing and installing
- Remove cylinder head as described in 113 Cylinder Head
Removal and Installation.
CAUTIOI\C
(M52 TU/M54 engines only) Do not let the hydraulic lifters
fall out as the camshaft carrier is removed. Special suction
cups are available from
BMW to hold the hydraulic lifters in
place during carrier removal.
* Hydraulic cam lifters should be stored m an uprfght po-
sition. If necessary, use a magnetic tool to
aidin remov-
al of the lifters.
- Remove valves using a valve spring compressor.
CAUTIOI\C
Label each valve assembly as it is removed so it can be in-
stalled in its original position.
-
- Remove and discard valve stem oil seals from valve guides.
See Valve stem oil seals later in this section.
- Valve installation is reverse of removal. Remove carbon de- - -
posits from the valves using a wire brush or wire wheel. -
-
Valve specifications are listed in Table c. Valve specifica-
tions.
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Camshaff Timing Chain
NOTE-
Mark direction of belt rotation if reusing belt.
- Remove vibration damper mounting bolts and remove vibra-
tion damper and pulley from hub.
NOTE- The M52
6-cylinder engine uses a 2-piece vibration damper
and hub assembly.
4 Install crankshaft holder (BMW special tools 11 2 150
and11 2410).
NOTE
-
Be careful while aligning locator pin hole in special tool 11 2
410 with vibration damper locatorpin.
- While counterholding crankshaft, loosen and remove crank-
shaft center bolt.
CAUTION-
Do not use flywheel locking tool to hold crankshaft stationary
to loosen or tighten crankshaft hub center bolt Use only the
special tools specified, or equivalent hub holding tool.
NOTE- The cranlshaft hub center bolt is torqued to 4
10 Nm
(300
ft-16).
- Remove damper hub and special tools.
4 Install cap (BMW special tool 11 2 383) on end of cranltshaft.
4 Install seal guide (BMW special tool 11 2 385) over end of
crankshaft. Be sure to align tool with keyway on crankshaft
(arrow).
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Camshaft Timing Chain
lnstall vibration damper mounting bolts. Note hub locating
dowel (arrow).
Tightening torque
Vibration damper to crankshaft hub
(ME) 22 Nm (16 ft-lb)
- Installation is reverse of removal noting the following:
Installing drive belts. See 020 Maintenance.
Install cooling fan. See 170 Radiator and Cooling Sys-
tem.
Crankshaft oil seal, replacing
(M52 TU and M54 engines)
The crankshafl front seal IS located in the lower timing cover,
behind the
vibrat~on damper.
- Disconnect negative (-) cable from battery.
Disconnecting the battery may erase fault
code(s) storedin
control module memoy Checlc for fault codes using spe-
cial
BMW diagnostic equipment.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.
- Remove splash guard from beneath engine
- Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
NOTE- Cooling fan nut
(32 mm wrench) has left-hand threads.
- Remove drive belts. See 020 Maintenance
NOTE-
Mark direction of belt rotation if reusing belt.
- Install crankshaft holding tool (BMW special tool 11 8 19011 1
8 200). Make sure tool locks into place in openings in damper
assembly. While counterholding crankshafl with special tool,
remove crankshaft center bolt.
CAUTIOI\C
Do not use flywheel locling tool to hold crankshaft station-
ary to loosen or tighten
cranl(shaft hub center bolt. Use
only the special tools specified, or equivalent hub holding
tool.
Use care when removing
damper/hub assembly, as ~t is
easy to damage the radiator