1999 BMW 540i Oul

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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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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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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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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 Timina chain1
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CA UTlOEIC
The radiator cooling fan nut (32mm wrench) has left- hand
threads.
.
< Remove engine trim covers:
Pry out plastic trim caps (arrows).
. Remove cover fasteners and covers.
4 Remove ignition coils:
0 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.
Disconnect VANOS electrical harness connector
(A) and oil
line fitting
(B) from VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
- Disconnect cranltcase breather by squeezing at arrows,
- Remove cylinder cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas.
kets should be reinstalled in their original positions. Make
note of their arrangement during removal.

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Camshaft Timing Chain
4 Disconnect VANOS electrical harness connector (A) and oil
line fitting
(B) from VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
Disconnect cranltcase breather by squeezing at arrows.
- Remove cylinder cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators andgas-
lets should be reinstalled in their original positions. Make
note of their arrangement during removal.
4 Remove oil baffle cover from intake camshaft

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4 With crankshaft at TDC position, remove vibration damper
bolts (arrows) and remove vibration damper.
< Mount crankshaft holding tool (BMW special tool 11 2 150
and
11 2 410) to crankshaft hub. Counter hold crankshaft and
loosen crankshaft hub retaining bolt.
Crankshaft hub retaining bolt is torqued to
410 Nm (300 ft-lb).
Do not use flywheel
locliing tool to hold cranl(shait stationary
to loosen or tighten crankshaft hub center bolt. Use only the
special tools specified, or equivalent hub holding tool.
- Remove crankshaft hub.
- Remove cylinder cover mounting fasteners and remove cyl-
inder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original positions. Make
note of their arrangement during removal.
- Drain engine oil, remove oil pan. See 119 Lubrication Sys-
tem.
Remove primary timing chain tensioner (arrow).
CAUTION-
Timing chain tensioner is under spring tension. I
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 engine).
- Remove fasteners from intake and exhaust camshaft
sprocket.