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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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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
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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.
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Camshaft Timing chain]
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.
- Align vibration damper assembly with keyway and tap into
place. Insert new center bolt with washer.
CA
UTIOG
Inspect woodruff key for damage before installing hub
assembly.
- Install crankshaft holding tool malting sure tool locks into
place in openings in damper assembly. While counterholding
cranltshaft, tighten crankshaft center bolt.
- Attach special tools 11 8 20011 1 8 190 to damper assembly.
Counterhold damper with 11 8 190 while tightening center
bolt.
Tightening
torque
Vibration damper hub to crankshaft 410 Nm (302 it-ib)
- Installation is reverse of removal noting the following:
Install drive belts. See 020 Maintenance.
Install cooling fan. See 170 Radiator and Cooling Sys-
tem.
Crankshaft oil seal, replacing
(M62 and M62 TU engines)
- Disconnect negative (-) cable from battery
CAUTIOG
Disconnecting the battery may erase fault code(s) storedin
control module memory. Check for fault codes using spe-
cial BMW diagnostic equipment.
* Prior to disconnecting the battery, read the battery dis-
connection cautions 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-
Marlc direction of belt rotation if reusing belt.
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Camshaft Timing Chain
VANOS timing, checking and adjusting
(M52 engine)
NOTE-
* Special BMW service tools are required to remove and in-
stall the VANOS control unit. Read the procedure through
before starting the job.
If the camshafts are not properly timed, the pistons can
contact the valves.
- Disconnect negative (-) cable from battery.
CAUTIOG Disconnecting the battery may erase
faultcode(s) storedin
control module memory. Prior to disconnecting the battery,
checlc for fault codes using special BMW diagnostic equip-
ment.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CAUTIOG The radiator cooling fan nut
(32 mm wrench) has left-hand
threads.
4 Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and remove coils.
Remove
spark plugs.
NOTE-
Make note of ignition coil ground strap locations.
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Camshaft Timing chain1
Tap locating dowels into cover until they protrude 2 to 3 mm
from sealing surface.
- Using new gaskets, install lower timing chain cover:
Tap cover into position to engage dowels.
Install timing chain cover fasteners and tighten to
5 Nm (44
in-lb).
Drive dowels in flush to front of cover.
. Tighten cover mounting bolts alternately and in stages.
Install cylinder head to timing chain cover fasteners and
tighten.
Tightening torques Lower timing chain cover to block
M7 15 Nm (1 1 ft-lb)
ME 20 Nm (15 it-lb)
- Replace front crankshaft radial seal. See Crankshaft oil
seal, front, replacing
(M52 engine).
Install engine oil pan using
a new gasket. See 119 Lubrica-
tion System.
Mount primary timing chain sprocket to primary
cha~n so that
arrow on sprocket faces up. Mount sprocket to camshafl so
that tapped holes in camshaft are on left side of elongated
holes in sprocket.
4 Install adjustable timing chain tensioner (BMW special tool
11 4 220). Thread tool in finger tight until slack is removed
from chain.
NOTE-
BMW special tool 11 4 220 is an adjustable timing chain ten-
sioner that simulates the function of the hydraulic tensioner.
- Check that elongated holes in primary sprocket are centered
to bolt holes in camshafl and chain is free of slack.
- Install secondary timing chain guide and secondary chain
tensioner. Tighten mounting bolts (tensioner remains
locited
down).
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-- Camshaft Timing Chain -- -
Tightening torque
Vibration damper hub to crankshaft
410 Nm (300 ft-lb)
4 Install cranltshaft hub and vibration damper while aligning
locating hole (arrow) in damper with dowel pin in hub.
Tightening torque
Vibration damper and
pulley to
cranltshaft hub
22 Nm (17 ft-lb)
- Turn engine over by hand in direction of rotation at least two
full rotations. Reinstall camshaft and crankshaft locking
toois
to recheck engine timing. Remove locking tools if no faults
are found.
- Remove BMW special tool 11 3 390 (dummy tensioner) from
side of cyiinder head.
- Install primary chain tensionerso that cutout in tensioner pis-
ton engages chain rail.
Tightening torque
Timing chain tensioner to tensioner sleeve
70 Nm (52 ft-ib)
- Install cylinder head cover mounting studs, camshaft cover,
and cylinder head cover.
Tightening torque Cylinder head cover to cyiinder head
M6 nut 10 Nm (89 in-lb)
MB bolt 22 Nm (17 ft-lb)
- installation of remaining parts is reverse of removal, noting
the following:
When installing thermostat, make sure arrow or vent hole
faces up, if applicable.
Refill cooling system as described in
170 Radiator and
Cooling System.
Fill engine with oil and install new
oil filter as described in
020 Maintenance.
Tightening torque Upper timing chain cover to cylinder head
M6 nut 10 Nm (89 in-lb)
MB bolt 22 Nm (17 ft-lb)
VANOS oil supply pipe to VANOS control
unit banjo bolt
32 Nm (24 ft-ib)
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Camshaft Timing Chain
VANOS control unit, removing
(M52 TU and M54 engines)
This procedure includes removal of the Double VANOS con-
trol unit.
NOTE-
If the Double VANOS control unit is being replaced, camshaft
timing must be checked. This procedure requires multiple
special tools. Be sure to read the procedures through before
beginning the repair.
- Working inside luggage compartment, disconnect negative
(-) battery cable.
Prior to disconnecting the
batteg read the battery discon-
nection cautions given in
001 General Cautions and
Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
Remove engine trim covers.
Pry out plastic trim caps (arrows).
Remove cover fasteners, oil filler cap, and covers.
Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and coils.
NOTE-
Make note of ignition coil ground strap locations.
Remove spark plugs,