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Cylinder Head and Valvetrain
< Disconnect fuel injector electrical connectors from injectors.
Pry corner of wire lock clip (arrow) on first injector.
* Repeat for all injectors.
Lift wiring ducts off and set aside.
4 Remove right and left side ignition coil mounting nuts (ar-
rows) and coils.
NOTE-
Male note of location for ground straps (arrow A).
- Remove spark plugs.
- Disconnect positive (+)jumper junction from top of lefl cylin-
der head cover.
4 Remove retaining nuts (arrows) and remove oil lines from
left and right cylinder heads.
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Cylinder Head and valvetrain'
Fit sensor gear with mark (arrow) pointing upwards. Install
bolts and finger tighten.
4 Attach BMW special tool 11 7 380 to right cylinder head in
place of upper timing case cover.
Install BMW special tool
11 3 390 into 11 7 380.
Using BMW special tool 00 9 250, tighten adjustable ten-
sioner screw on
11 3 390 to 0.7 Nm (6.3 in-lb).
- T~ghten camshaft sprocket bolts in the following order:
1. Exhaust camshaft, left head.
2. Exhaust camshaft, right head.
3. Intake camshaft, left head.
4. Intake camshaft, right head.
Tightening torques Sprocket
to camshaft flange 15 Nm (I 1 ft-lb)
- Remove camshaft locking tools from both cylinder heads.
- Remove crankshaft locking tool.
4 lnstall oil lines to left and right cylinder heads.
- Remove adjustable timing chain tensioner tool and setup
block from right cylinder head.
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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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Table d. Valve guide specifications
Specifications
All engines (1997-2002)
Valve guide wear, maximum 0.5 mrn (0.020 in)
(valve tilt clearance
measured
with new valve)
Valve guide inside diameter,
installed
(tolerance per IS0 allowance H7)
Standard 6.0 mm (0.236 in)
Oversize
1 6.1 mrn (0.240 in)
Oversize 2 6.2
mm (0.244 in)
Valve stem oil seals
The purpose of the valve stem oil seal is to prevent excess oil
from entering the combustion chamber. The sign of faulty
valve stem oil seals is excessive oil consumption and smoke
from the exhaust immediately after starting and during decel-
eration.
NOTE-
Valve stem oil seals should not be reused. If valves are re-
moved, new valve stem oil seals should be installed.
Valve stem oil seal replacement requires that the cylinder
head be disassembled and the valves removed as described
above under Valves, removing and installing.
NOTE-
BMW special tools are available to remove the valve stem oil
seals. As an alternative, standard valve seal removal tools
are available from most automotive parts stores.
Lubricate new seal and install using hand pressure only. Be
sure to install valve spring
seat(s) before installing seal.
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11 7 Camshaft Timing Chain
General ........................... .I I 7-2 Double VANOS System
Special tools ........................ .I 17-2 (M52 TU and M54 engines) ......... 11 7-34
Crankshaft Oil Seal, Front ........... I 17-6
Crankshaft oil seal, front,
replacing
(M52 engine) ................ .I1 7-6
Crankshaft oil seal, replacing
(M52 TU and M54 engines) ............ .I 17-9
Crankshaft oil seal, replacing
(M62 and M62 TU engines) ........... .I1 7-1 1
VANOS Control Unit and
Timing Chain
(M52 engine) ........ ,117-14
VANOS control unit, removing
(M52 engine) ...................... ,117-1 4
VANOS control unit, installing
(M52engine) ....................... 117-19
VANOS timing, checking and adjusting
(M52 engine) ...................... .I1 7-22
Timing chains, removing (M52 engine) . . ,117-26
Timing chain, installing (M52 engine) .... ,117-30
bouble VANOS system Tunctidn ........ 11 7-34
Double VANOS control unit ............ 117-36
VANOS control unit, removing
(M52 TU and M54 engines) ............ 11 7-37
VANOS control unit, installing
(M52 TU and M54 engines) ............ 1 17-41
VANOS timing, checking and adjusting
(M52 TU and M54 engines) ............ 1 17-43
Timing chains assembly
(M52 TU and M54 engines) ............ 1 17-50
Timing chains, removing
(M52 TU and M54 engines) ............ 11 7-51
Timing chains, installing
(M52 TU and M54 engines) ............ 11 7-57
Timing Chain (M62 engine to 9/98) . . 117-66
Timing chains, removing
(M62 engine to 9/98) ................. 11 7-66
Timing chains, installing
(M62 engine to 9/98) ................. 1 17-74
Camshaft timing, checking and adjusting
(M62engine) ....................... 117-79
Page 242 of 1002
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Camshaft Timing Chain
4 Crankshaft hub loclting tool. M54 engine
(Tool No.
BMW 11 8 190 11 1 8 200)
4 VANOS test lead, M52 6-cylinder
(Tool No.
BMW 12 6 410)
Crankshaft oil seal, front,
replacing
(M52 engine)
The crankshaft front seal is located in the lower timing cover,
behind the vibration damper.
- Disconnect negative (-) cable from battery.
CAUTIOIG
a Disconnecting the battery may erase fault code(s) stored in
control module memory Check
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
Warninqs.
- Remove splash guard from beneath engine.
- Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
NOTE-
Cooling ian nut (32 mm wrench) has left-hand threads.
- Remove drive belts. See 020 Maintenance.
,~R,~",,,~"P,,,,!,.,,,.,"?,,m-A,, P,",,,s
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1 17-8
Camshaft Timing Chain
4 Install oil seal puller (BMW special tool 11 2 380) and screw
in body of puller until it contacts seal. Tighten center screw to
draw seal out of cover.
4 Coat new seal with oil and position in timing chain cover. Use
BMW special tool
11 3 280 and crankshaft center bolt to draw
seal in flush with timing case cover.
4 Align hub with keyway and tap into place. Insert new center
bolt with washer shoulder
(arrow) facing hub.
CAUTION-
Inspect woodruffl
- Reinstall cranltshaft holder tool.
NOTE-
Be careful while aligning locator pin hole in special tool 1 I 2
410 with vibration damper locator pin.
- While counterholding cranltshaft, tighten crankshaft center
bolt.
Tightening torque Vibration damoer hub
to crankshaft 410 Nm (302 ft-lb)
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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