Page 235 of 1002

Downloaded from www.Manualslib.com manuals search engine
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.
Page 238 of 1002

Downloaded from www.Manualslib.com manuals search engine
1 17-2
Camshaft Timing Chain
This repair group covers timing chain and VANOS repair
information for the following engines:
M52 (Single VANOS 6-cylinder engine)
M52
TU and M54 (Double VANOS engines)
M62 (Non VANOS
V-8 engine)
NOTE-
The M62 TU V-8 engine with VANOS Variable Camshaft
Timing repair information is not included.
NOTE-
See 100 Engine General for engine code and application
information.
Worn timing chains and sprocltets can lead to noisy operation
and erratic valve timing. Afaulty tensionercan also cause tim-
ing chain noises.
For specific repair procedures, refer to the appropriate repair
group:
020 Maintenance
113 Cylinder Head Removal and Installation
119 Lubrication System
121 Ignition System
170 Radiator and Cooling System
Special tools
Special BMW service tools are needed to perform the service
and repairs procedures covered in this repair group. Many of
these tools are expensive and only available through an au-
thorized BMW dealer. Be sure to read each procedure thor-
oughly before starting a job to determine which special tools
will be necessary.
In addition, Double VANOS system diagnosis can only be
carried out by using BMW specific electronic scan tools, such
as BMW
DISplus, MoDiC or equivalent.
4 Torque wrench wl flex extension
(Tool No. BMW 00
9 250)
Page 262 of 1002

Downloaded from www.Manualslib.com manuals search engine
Camshaft Timing Chain Timing chains, removing
(M52 engine)
Camshaft timing chain removal on M52 engines requires en-
gine oil pan removal.
Special
BMW sewice tools are needed for timing chain re-
moval and installation procedures. The special tools assure
propertiming of thevalvetrain. Precise marks to
setthe timing
on the camshafts are not provided for reassembly. Read the
procedures through before beginning the job.
NOTE-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- Remove VANOS control unit. See VANOS control unit, re-
moving (M52 engine).
- Remove radiator cooling fan and shroud. See 170 Radiator
and Cooling System.
- Drain cooling system. See 170 Radiator and Cooling Sys-
tem.
- Remove coolant hoses from thermostat housing and remove
thermostat housing from front of cylinder head.
- Loosen bolts for coolant pump pulley.
- Remove drive belts for alternator and AIC compressor. See
020 Maintenance.
- Remove coolant pump pulley.
Remove drive belt tensioner mounting bolts (arrows) and re-
move tensioner from front of engine.
- Remove engine speed sensor from lower timing chain cover.
Page 265 of 1002
Downloaded from www.Manualslib.com manuals search engine
Camshaft Timing chain1
Using a drift, drive two locating dowels (arrows) in lower
timing cover toward rear of car.
4 Remove timing cover mounting bolts (arrows).
* Carefully slide cover with water pump forward to remove
CAUTION-
Use care when removing the cover from the cylinder head
gasket If the cover is stuck, use a sharp knife to separate
it from the head gasket.
If cylinder head gasket is damaged, remove cylinder
head and replace head
gaslet. See 113 Cylinder
head and valvetrain.
- Remove timing cover locating dowels by driving them
forward.
- Lift primary chain sprocket off crankshaft sprocket and
remove chain.
Page 274 of 1002
Downloaded from www.Manualslib.com manuals search engine
11 7-38
[Camshaft Timing Chain
4 Disconnect electrical harness connector (A), oil line fitting
(B), and cranltcase vent tube (squeeze at arrows).
NOJE-
Oil will drain from VANOS unit fitting. Use shop rags to keep
oil off drive belts.
- Remove cylinder head cover fasteners, and cover.
4 Remove oil baffle cover from intake camshaft
4 D~sconnect electrical connections from exhaust camshaft po-
sition sensor and VANOS control valve (arrows).
4 Using banjo bolt from VANOS control unit oil line, install test
fitting
(BMW special tool 11 3 450) to VANOS control unit.
Page 279 of 1002

Downloaded from www.Manualslib.com manuals search engine
Camshaft Timing Chain
- Connect electrical harness connectors to camshaft position
sensors and VANOS solenoid valves.
- Remove BMW special locking tools from rear of cylinder
head.
- Remove cranltshaft locking tool and replace sealing plug.
Install intake camshaft baffle and cylinder head cover.
Checlc for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond 1209
O or equivalent
sealant at corners
(B) of half-moon cutouts.
Similarly, seat gasket and
seal corners in front of cylinder
head, at VANOS control unit.
Tightening torque
Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Remainder of installation is reverse of removal.
Tightening torques
Radiator fan (viscous clutch) to
coolant pump 40
Nm (30 ft-lb)
Spark plug to cylinder head
25 Nrn (18 ft-lb)
VANOS timing, checking and adjusting
(M52 TU and M54 engines)
Use this procedure to check and, if necessary, adjust cam-
shaft timing. This procedure assumes that the cylinder head
cover and intake
camshaft plastic baffle have been removed.
Also, be sure the cooling fan and the spark plugs have been
removed.
Remove primary camshaft chain tensioner cylinder
(arrow).
~~ ~ ~~ ~--~
CA UTlOAC
Primary camshaft chain tensioning piston is under spring
pressure.
Page 292 of 1002

Downloaded from www.Manualslib.com manuals search engine
~ ~~ ~
I Camshaft Timing Chain I --
lnstall crankshaft holding tool (BMW special tool 11 8 190/11
8 200). Make sure cut outs in tool engages openings in
damper assembly. While counterholding crankshaft with
special tool, remove crankshaft center bolt (A).
CAUTION-
Do not use flywheel locking tool to hold crankshaft stationary
NOTE-
The crankshaft hub centerbolt is tightened to a torque of 410
Nm (300 ft-lb).
4 Install crankshaft damper puller (BMW special tool 11 8 210)
to 11 8 200. and (A) remove damper from crankshaft.
The crankshaft must not be allowed to rotate when the timing
chains are loosened or removed. The pistons can contact the
valves. Use appropriate crankshaft holding tool when loosen-
ing crankshaft hub center bolt.
Using a drift of less than
5 mm diameter, drive two locating
dowels in left and right sides of lower timing
cham cover to-
ward engine. Remove cover mounting bolts
(arrows) and
carefully lift cover off.
CA
UTION-
* Use care when removing the cover from the cylinder heao
gasket. If the cover is stuck, use a sharp
knife to separate
it from the headgasket.
If cylinder liead gasket Is damaged, remove cylinder
head and replace head gasket. See
113 Cylinder
head and valvetrain.
NOTE-
- The chain cover can be removed with the coolant pump in-
stalled.
Use care when removing the cover from the coolant pipe
at rear.
- Push primary chain tensioner guide rail aside and remove
chain.
Page 302 of 1002

Downloaded from www.Manualslib.com manuals search engine
11 7-66
I Camshaft Timing Chain
4 install 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
1209 8 or equivalent
sealant at corners
(B) of half-moon cutouts. Seal corners
in front of cylinder head at VANOS control unit.
Tightening torque
Cylinder head cover to cylinder head
10 Nm (89 in-lb)
- Remainder of reassembly is reverse of removal, noting the
following:
Secure all coolant hoses, thermostat housing, engine cool-
ant drains.
Install new engine oil filter and oil. See
119 Lubrication
System.
Refill and bleed cooling system as described in
170 Radi-
ator and Cooling system.
Use scan tool to check VANOS operation with engine
idling.
Tightening torques Coolant drain plug to cylinder block
25 Nm (18 ft-lb)
Radiator cooling fan (viscous clutch)
to coolant pump
40 Nm (30 ft-lb)
Radiator drain screw to radrator 2.5 Nm (22 in-lb)
Vibration damper hub to crankshaft 41 0 Nm
(300 ft-ib)
TIMING CHAIN
(M62 ENGINE TO 911998)
Timing chains, removing
(M62 engine to 911 998)
Camshaft timing chain removal requires that the engine oil
pan be removed.
Special
BMW service tools are needed for timing chain re-
moval and installation procedures. The special tools assure
propertiming of thevaivetrain. Precise marks to set the timing
on the camshafts are not provided for reassembly. Read the
procedures through before beginning the job.
CAUTION-
Special BMW service tools are needed for this procedure.
Read the procedure through before beginning the job. If the
camshafts are notproperly timed, the pistons can contact the
valves.