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Cylinder Head and Valvetrain
NOTE-
The camshaft bearing caps are coded with a letter and a
number. For example, "A
1" is the first exhaust camshaft
bearing cap
at the front of the engine, and "El "is the intake
camshaft bearing cap at the front of the engine.
-. -
The camshafts are stamped with a code letter - "E for the
intake side and
'X" for the exhaust side.
"E is for Einlap. (German for intake) and 'XA7s for Auspuff.
(German for exhaust).
- Repeat procedure for exhaust camshaft
< Secure hydraulic lifters in lifter bores using BMW special tool
11 3 250, or remove lifters using a magnetic pick-up tool.
I CAUTION-
Used liydraulic lifters must be reinstalled in original lifter
1 bores.
4 Remove lower camshaft bearing carriers from cylinder head.
CAUTION- Camshaft bearing carriers must be reinstalled in their original
locations
(E for intalce and A for exhaust).
NOTE- Do not allow hydraulic lifters to fall out of camshaft carriers.
Hydraulic lifters should be stored in an upright position.
Camshafts and lifters, installing (M52TU and M54 engine)
Lubricate camshafts, camshaft carriers, bearing caps, hy-
draulic lifters, friction washers, splined shafts and
spline hubs
with assembly
lubricant before installation.
CAUTION-
Make sure the crankshaft, which had been rotated approxi-
mately
30" opposite the direction of engine rotation from
TDC, is
stillin thatposition before lowering the camshafts into
position. Allpistons must be out of
TDCposition to prevent
valve/piston inteiference when the carnshafis are installed.
- Lift timing chain and place exhaust cam onto exhaust cam-
shaft carriers. Place
intake camshaft on camshaft carrier.
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11 6-26
I Cylinder Head and Valvetrain
4 Before installing camshaft carriers, examine bearing bores
(arrows) on hydraulic lifter bores for signs of wear.
Install camshaft carriers with hydraulic lifters into cylinder
head. Note marks on carriers:
(E) for intake side and (A) for
exhaust side.
4 Center camshaft carrier on pins (arrows) at bearing
aositions 2 and 7.
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-- - . .- -,
Cylinder Head and Valvetrain
4 Rotate camshafts so that intalte and exhaust lobes for cylin-
der
1 face each other (arrows).
CAUJION-
A minimum waiting time is required for the hydraulic lifters to
'bleed down"after installing the camshafts into the cylinder
head, before bringing the piston to TDC. When the camshafts
are removed, the hydraulic lifters can expand. This expan-
sion can cause increased valve lift when the camshafts are
bolted down, possibly resulting in piston interference.
Place bearing caps on cams, but do not install retaining nuts.
4 Fit BMW special tool 11 3 260 (A) and 11 3 270 (B) to cylinder
head over
intalte camshaft and screw long bolts (arrows)
into spark plug threads.
CA UTION-
Do not overtighten bolts into spark plug holes.
< Turn eccentric shaft of special tool to pretension bearing
caps. Install and torque nuts on intake camshaft bearing
caps.
Tightening torque Camshaft bearing cap
to cylinder head (M7) 14 Nm (10 it-ib)
- Release tension on eccentric shaft and remove BMW special
tools
11 3 2601270.
- Repeat procedure for exhaust camshaft.
NOTE-
Observe waiting time for lifter bleed down before continuing
with camshaff installation.
Crankshaft
I valve timing waiting times
68°F (20°C) and higher 5 minutes
50-6S°F(10-20°C) 15 minutes
32-50DF(O-10°C) 30 minutes
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--
Cylinder Head and valvetrain1
Double VANOS secondary timing chain components,
installing
(M52 TU, M54 engine)
< Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 If necessary, turn camshaft so that special tools are squarely
seated on cylinder head.
4 Lift timing chain and hold under tension
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11 6-46
/cylinder Head and Valvetrain
I I Camshafts, installing, right cylinder head (M62 engine)
I
1
A: / Camshafts are marked at rear. Install camshafts into cam-
shaft bearing saddles of cylinder heads.
Intake camshaft for right cylinder head
(14) is labelled
E 1-4.
Exhaust camshaft for right cylinder head (1-4) is labelled
A 1-4.
4 Rotate camshafts so that recesses in Intake and exhaust
camshafts
polnt upward 30 to 40' above seal~ng surface for
valve cover (arrows).
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
'N" for the exhaust side. Number code is
forposition on head, with number
7 being the front bearing
cap.
CAUTION--
Do not mix up camshafi bearing caps between cylinder
banks.
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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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1 16-50
/Cylinder Head and Valvetrain
4 Rotate camshafts until marker bores (insets) point upwards,
4 Secure camshafts in TDC position using BMW special tools:
Cylinders 5-8 Align camshafts w~th open-end 27 mm wrench so BMW
special tools fit on cylinder heads without gaps. Secure
11 2 242 11 2 446 I tool using number 8 cylinder spark plug hole.
CAUTION-
Do not damage the cylinder head. If necessary, machine
open-end wrench to
fit.
Timing chains and tensioners, installing (M62 engine)
4 Fit secondary sprocltets and chain to camshafts on right cyl-
inder head. Center slots in sprocltets to threaded bores in
end of camshafts (arrows).
. .
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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.