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1 16-48
/Cylinder Head and Valvetrain
Cylinders
1-4
11 2 445 11 2441
4 Secure camshafts in TDC position using BMW special tools:
Align camshafts with open-end
27 mm wrench so BMW
special tools fit on cylinder heads without gaps. Secure
tool using number 4 cylinder spark plug hole.
Do not damage the cylinder head. If
necessa& machine
open-end wrench to fit.
Left side (cyl.
5-8) camshafts, installing (M62 engine)
4 Camshafts are marked for location at rear. Install camshafts
into camshaft bearing saddles of cylinder heads, noting the
following:
Intake camshaft for left cylinder head
(5-8) is labelled
E 518.
Exhaust camshaft for left cylinder head (5-8) is labelled
A
518.
4 Rotate camshafts so that recesses in intake and exhaust
camshafts point downward 30 to 40" (arrows) from cylinder
head cover sealing surface.
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Cylinder Head and valvetrain1
4 Bearing caps are marked with a code for location.
NOTE-
The camshaft caps are stamped with a code letter - "E for
the intake side and
'HA" for the exhaust side. Number code is
for position on head, with number
1 being the front bearing
cap.
CA UTIOI\C
Do not mix up camshaft bearing caps.
Install and evenly tighten down bearing cap nuts in
'I2 turn
steps starting at number
1.
Tightening torque
Camshaft bearing cap 14 Nrn (10 ft-lb)
4 Install BMW special tool 11 3 430 on camshaft.
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Cylinder Head and valvetrain1
Install exhaust camshaft bolts (arrows) finger tight.
Remove secondary timing chain tensioner
loclting tool.
< Fit secondary sprockets and chain to camshafts on left cylin-
der head. Center slots in sprocltets to threaded bores in end
of camshafts
(arrows).
Insert exhaust camshaft bolts (arrows) finger tight in exhaust
camshaft on left cylinder head.
Remove secondary timing chain tensioner locking tools from
chain tensioners.
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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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- - . - 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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117-18
Camshaft Timing Chain
4 Loosen 4 bolts (arrows) from exhaust camshait sprocket
(Torx E10).
Press down on secondary chain tensioner and lock into place
using BMW special tool
11 3 292 or a similar size pin.
NOTE-
Two types of secondary timing chain tensioners are used;
one with two holes, and one with a single hole for the
locl
pin tool.
Remove VANOS control unit mounting fasteners at front of
cylinder head.
4 Install sprocltet rotating tool (BMW special tool 11 5 490) on
exhaust camshaft.
- Rotate exhaust camshaft sprocket clockwise while sliding
VANOS control unit forward to remove from cylinder head.