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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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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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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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-
- - . - Cylinder Head and Valvetrain -
Table c. Valve specifications
Valve head diameter
lntaite 33.0 mm 33.0 mm 35.0 mm
Exhaust
30.5 mm 30.5 mm 30.5 mm
Valve stem diameter
- Standard
Intake
6.0 mm .0.025 6.0 mm -O.o" .o.040 6.0 mm .0.025 .0,040
Exhaust 6.0 mm -0.0"0 -0.055 6.0 mm -0.040 .0,055 6.0 mm .0.040 .0,055
Valve stem diameter - Oversize 1 (identified on stem as Rl)
Intake 6.1 mm -0.025 .0.040 6.1 mm .0-025 .0,040 6.1 mm -O.o" .o,040
Exhaust 6.1 mm .O.O4O ..,,,, 6.1 mm -0.040 -0.055 6.1 mm -0.040 .0,055
Valve stem diameter - Oversize 2 (identified on stem as R2)
Intake 6.2 mm -O-OZ5 6.2 mm -0.025 .0.040 6.2 mm -0.025 .0,040
Exhaust 6.2 mm -0.040 -0.055 6.2 mm -0.040 .o.055 6.2 mm -O."o .o,055
Valve guides
BMW does not supply valve guides as replacement parts. If a
valve guide is excessively worn, it should be reamed to ac-
cept oversized
valve stems. Valve guide specifications are
listed in
Tabled. Valve guide specifications.
- Valve guides should be checked for wear using a new valve.
Be sure to thoroughly inspect the cylinder head to ensure
that it can be reused before reworking the guides.
NOTE-
International Organization for Standardization (1.30) toler-
ance classes are listed in Table c.
IS0 allowances are
based on nominal sizes and should be used to determine
proper fit. Most machine shops should have this informa-
tion available.
Replacement valve guides may be available through after-
market suppliers. Valve guide replacement requires spe-
cial tools and a press. It is also necessary to heat the
cylinder head and chill the valve guides when replacing the
guides.
BMW supplies oversize valves. See Table d. Valve guide
specifications for additional information.
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Cylinder Head and valvetrain1
Valve seats
< The valve seats should be resurfaced whenever new valves
or valve guides are installed. Cutters are required to resur-
face the seats. Always check the valves for leaks after recon-
ditioning a valve seat as described above. Table e. Valve
seat specifications lists valve seat dimensions.
Table e. Valve seat specifications (refer to figure)
All
6 cylinder All 8 cylinder
engines (1997- engines (1997- Specification 2002) 2002)
Blllloc A -Valve seat angle 45" --. -- 45"
B - Correction angle, 15" 15"
outside
C - Correction angle, 60"
inside
D -Valve seat width
intalte
1.65 i0.25 rnrn 1.25 +0.25 rnm
(0.065 c0.010 in) (0.049 f 0.010 in)
exhaust
1.65 c0.25 rnm 1.65 i0.35 rnm
(0.065 fO.O1O in) (0.065 c0.014 in)
E - Valve seat outside diameter
intake
32.4 mm (1.276 in) 34.5 mm (1.358 in)
exhaust
M52: 29.4 rnm 30.0 rnm (1.181 in)
(1.157 in)
- M52 TU,
M54: 30.0 mrn
(1.181 in)
NOTE-
Standard size replacement valve seats are not available from
BMW Replacement valve seats are only available from BMW
in 0.4 mm oversize (oversized in both height and diameter).
The manufacturer does not provide specifications for valve
seat replacement for the engines covered by this manual.
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11 6-60
Cylinder Head and Valvetrain
Valve springs
The valve springs should be checked for fatigue. To quickly
check the springs, line them up in a row. Place astraight edge
across the top of the springs. Any spring that is significantly
shorter than the others is worn and should be replaced.
Valve spring specifications and wear limits are not available
from
BMW.
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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.
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