engine BMW 540i 1998 E39 Workshop Manual

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11 6-5
I Cylinder Head and valvetrain1
4 Timing chain tensioner bracket (V-8)
(Tool No. BMW
11 7 380)
CYLINDER HEAD
This section provides the specifications and special recondi-
tioning information necessary to repair the cylinder heads
covered by this manual.
The disassembled cylinder head should be inspected for
warpage and cracks. Check the valve guides and valve seats
for wear before machining a warped head. Always decarbon-
ize and clean the head before inspecting it.
Visually inspect the cylinder head for craclts.
If a cracked cyl-
inder head is suspected and no
craclts are detected through
the visual Inspection, have the head further tested for cracks
by an authorized BMW dealer or an ASE certified machinist.
A cracked cylinder head must be replaced.
NOJE-
When disassembling and inspecting the cylinder head, be
sure to
checlc the camshaft carrier bearing surfaces using a
straight edge for
warpage, and check the lifter bores for wear.
A high-quality straight edge can be used to
checlc for
warpage. A warpage of 0.05 mm (0.002 in.) is acceptable
without machining. A warped cylinder head can be machined
provided no more than 0.3
mm (0.012 in.) of material is re-
moved.
If further machining is required, the head should be
replaced. Removing more than this amount will reduce the
size of the combustion chamber and adversely affect engine
performance. A 0.3 mm
thicker head gasket for machined
heads is available from an authorized BMW parts depart-
ment.

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11 6-6
Cylinder Head and Valvetrain
4 Before machining the head to correct for warpage, measure
the total height
(A) (thickness of the cylinder head). Minimum
height specifications are given in Table a. Cylinder head
height.
NOTE-
6 cylinder and V-8 engines share cylinder head height spec-
ifications.
Table a. Cylinder head height
New Minimum height
(A)
140.0 rnrn (5.512 in.) 139.7 rnrn (5.500 in.)
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.
Camshaft wear
Camshaft wear is usually caused by insufficient lubrication.
Visually inspect camshaft lobes and journals for wear. Cam-
. ~~ shaft wear specifications are given in Table b. Camshaft
wear specifications.
CA UTIOI\C
If the camshaft is being replaced due to cam lobe wear, it is
recommended that the corresponding lifters should also be
replaced to avoid damaging the new camshaft
Table b. Camshaft wear specifications
6 cylinder engines V-8 engines
Axlal play 0.150-0.330 rnrn 0 200-0 360 rnrn - .-
(0.0060-0 013 in.) (0.008 - 0.014 in ) - - Radlal play 0.020-0.054 rnrn 0.040-0.074 rnrn
(0.0008-0.0021 in.) (0.016 - 0.029 in.)

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Cylinder Head and valvetrain1
Hydraulic lifters, checking and replacing
Self-adjusting hydraulic lifters (A) keep the valve clearances
within a limited working range. Hydraulic lifters are sealed
units and require no maintenance. Section view of camshaft
(6) and valve with conical valve spring (C) shown.
Under some circumstances, such as a cold start, the cam fol-
lowers may emit noise. Hydraulic lifter noise is usually a
high-
pitched tapping or chattering noise. In most instances, this is
considered normal as long as the noise goes away in a few
minutes (maximum
20 minutes). If the noise does not go
away, either the lifter is faulty or the oil pressure to the lifter is
low. Hydraulic lifter replacement requires that the camshaft
first be removed.
NOTE-
Before checking hydraulic lifters, male sure engine oil is
fresh and at the proper level.
Sticky lifters can be the result of
sludge build up in the cylinder head and lifters.
- Run engine until it reaches normal operating temperature.
Shut off engine.
- Working inside luggage compartment, disconnect negative
battery cable.
CAUTION-
Prior to disconnecting battery cable, read the baltery dls-
connection cautions given In 001 General Cautions and
Warnings.
Disconnecting the battery may erase fault
code(s)
stored in control module memory Check for fault codes
4 Remove left and right interior ventilation duct (left side
shown):
Release plastic locking tab
(A) or release loclting tabs on
top of duct (later models).
Rotate duct counterclockwise to
unloclt from bulithead and
remove (arrow).

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Cylinder Head and Valvetrain
&cylinder models: remove plastic top
- Pry out caps (arrows).
- Remove fasteners and covers. covers:
4 V-8 models: remove plastic top
covers:
Press down on locking pins
(arrows) to release locks and
remove top cover.
Pry out caps
(A) from covers.
Remove fasteners and covers.
4 Lift metal latch on coil harness connectors and disconnect
harness connectors from coils. 6-cylinder shown,
V-8 similar.
- Remove coil grounding straps.
NOTE-
Make note of ground wire at mounting studs arrangement
during removal.
- -- -
-

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11 6-9
Cvlinder Head and valvetrain1
4 Remove ignition coils and spark plugs.
V-8 models: remove mounting nuts (arrows) from wiring har-
ness ducting.
< V-8 models: disconnect fuel injector electrical connectors
from injectors:
Pry one corner of wire
loclc clip (arrow) on first injector.
Repeat for all injectors.
Lift wire ducts off and set aside.
- V-8 models: disconnect battery jump start post terminal from
left cylinder head cover.
- 6-cylinder models: remove oil filler cap and unclip vent con-
nection from cylinder head cover.
- Remove cylinder head cover mounting fasteners and re-
move cylinder head cover(~).
NOTE-
The cylinder head cover mounting bolt insulators and gas-
Icets should be reinstalled in their original locations. Make
note of their arrangement
during removal.

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Cylinder Head and Valvetrain
< Remove oil baffle cover from above intake camshaft(s)
- Rotate engine at crankshaft vibration damper center bolt in
normal direction of rotation (clockwise) until camshaft lobe of
lifter to be tested points away from the lifter, allowing valve to
be completely closed.
Use a plastic or wooden stick to press down on top of lifter
with approximately 3.5 Nm
(2.25 ft-ib) of force.
If the lifter collapses slightly as though spring loaded, air
may be trapped in the lifter.
NOTE-
Air trapped in hydraulic lifters may result from oil foaming (air
being drawn
in by the oil pump). This may be caused by a
faulty oil pump control valve O-ring; leaking oil pump pickup
gaslcet; or by oil starvation to pump.
Press down on top of lifter for
10 to 15 seconds uslng approx-
lmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the
cam-
shafi lobe, the check valve in the lifter is not closing. Re-
place lifter.
- To replace a hydraulic lifter, remove appropriate camshaft.
Refer to camshaft removal procedures given in Camshaft
and lifter removal and installation.
Once camshaft is removed, withdraw faulty
lifter(s) and re-
place with new
lifter(s). Inspect lifter bores for wear and scor-
ing at arrows.
- Reinstall camshafts. See Camshaft and lifter removal and
installation.

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Cylinder Head and Valvetrain
4 Install intake camshaft oil baffle cover and cylinder head cov-
er:
= Checlc for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond 1209
@or equivalent
sealant at corners
(B) of half-moon cutouts and corners in
front of cylinder head at joint to timing chain cover.
Align cover at front and rear, then alternatively tighten fas-
teners from inside to outside.
Tightening torque
Sparic plug to cylinder head 25 Nm (18 it-lb)
Ignition coils to cylinder head 10 Nrn (7.5 ft-lb)
Cylinder head cover to cylinder iiead 10 Nrn (89 in-lb)
fM6 screws)
CAMSHAFT AND LIFTER REMOVAL
AND ~NSTALLATION
The camshafts can be removed with the cylinder heads
mounted on the engine (in the car).
On 6-cylinder engines there are two different procedures giv-
en, depending on whether the engine is equipped with single
VANOS (M52 engine) or double VANOS
(M52TU or M54 en-
gine).
For V-8 engines, camshaft removal and installation proce-
dures are
only included for the non-VANOS (M62) engine.
Camshaft removal and installation for the
VANOS eq;ipped
V-8 (M62TU) is not covered in this manual.
Special BMW service tools should always be used to remove
and install the camshafts. Removal of the camshafts without
the special tools can result in cylinder head damage and cam-
shaft breakage.

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116-12
I Cylinder Head and Valvetrain
Camshaft and lifter removal and installation
(M52 engine)
Camshafts and lifters, removing (M52 engine)
WARNING
-
The process of evenly loosening the camshaft bearing cap
nuts is NOT an acceptable method of removing the cam-
shafts. Special tools should always be used to remove the
camshafts. Be sure to read the procedure
tlirough before
starting a job.
I Allow engine to cool before beginning this procedure. /
- Disconnect negative (-) cable from battery.
CAUTION-
Prior to disconnecting the batfew read the battery discon-
nection cautions given in
001 General Cautions and
Warnings.
- Remove VANOS control unit from cylinder head. See 117
Camshaft Timing Chain.
I I 4 Remove loosened bolts (arrows) from front of exhaust
sprocket
nuts
(arrows) from intake camshaft

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Cylinder Head and Valvetrain
I I < Remove outer thrust washer, sprinq plate, and inner thrust
washer.
4 Remove both camshait sprockets with secondary timing
chain.
NOTE-
Keep chain and sprockets together as an assembly for easier
installation.
< Remove thrust washer studs (arrows) and remove thrust
washer.

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116-14
I Cylinder Head and Valvetrain
4 Remove sensor gear (arrow).
Remove secondary timing chain tensioner retaining bolts
(arrows) and remove tensioner.
Remove timing chain guide
reta~ning bolts (arrows) and
remove guide.