2000 BMW 540i piston

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Lr -- - - - -- Cylinder Head Removal and Installation I -
- Release pressure at compression gauge valve, then remove
gauge from spark plug hole. Repeat test for each cylinder
and compare results with values given in Table a.
Table a. Compression testing specifications
Minimum compression
6-cylinder
10-1 1 bar (142-156 psi)
V-8 12-14 bar (174-203 psi)
Maximum difference between
cylinders (all engines)
0.5 bar (7 psi)
- Compression readings may be interpreted as follows:
Low compression indicates a poorly sealed combustion
chamber.
0 Relatively even pressures that are below specification nor-
mally indicate worn piston rings
andlor cylinder walls.
Erratic values tend to indicate valve leakage.
Dramatic differences between cylinders are often a sign of
a failed head
gasket, burned valve, or broken piston ring.
- If readings are within specifications, reinstall spark plugs and
ignition coils.
NOTE-
Used spark plugs should be reinstalled in the same cylinder
from which they were removed.
Tightening torque Spark plug to cylinder head 25 Nm
(18 ft-lb)
lanition coils to cylinder head 10 Nm (7.5 ft-lb)
- Remainder of installation is reverse of removal. Be sure to re-
install all wires disconnected during test, especially ground
wires at coils and cylinder head cover (where applicable).
Wet compression test
To further help analyze the source of poorcompression,awet
compression test is the next step.
- Repeat compression test, this time squirt a teaspoon of oil
into each cylinder. The oil will temporarily help seal between
piston rings and cylinder wall, practically eliminating leakage
past rings for a short time.
- If this test yields a higher reading than "dry" compression
test, there is probably leakage between piston rings and
cylinder walls, due either to wear or to broken piston rings.
- Little or no change in compression reading indicates other
leakage, probably from valves.

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113-16
Cylinder Head Removal and Installation
- Remove secondary timing chain and sprockets:
Remove mounting nuts from front of intake camshaft
sprocket. Remove and label shim.
CAUTION-
Hold the camshaft stationary (at hex on camshaft) when loos-
ening or tightening sprocket mounting fasteners.
Remove mounting nuts from front of exhaust camshaft
sprocket and remove and label thrust washer.
NOTE-
Where applicable, make note of thrust washerpositions. The
thicker
(0.4 mm) washer is mounted outermost.
- Remove secondary sprockets together with camshaft tim-
ing chain from front of camshafts.
CAUTION-
The camshafts must be locledin the TDCposition using the
special service tool as described earlier: The arrows on the
sprockets should not be used to accurately set the engine to
TDC. The tool holds the camshafts parallel to each other and
NOTE-
Do not remove the sprocl parts are being replaced. Wire tie each sprocket to the chain
to
Iceep the sproclefs timed to each other:
CAUTIOI\C
The crankshaft must not be allowed to rotate once the cam-
shaft timing chain is removed. The pistons can
contact the
valves.
Unscrew timing chain guide and remove.
Lift off primary sprocket with chain.
Secure chain with wire to prevent chain from dropping into
lower timing cover.
Unscrew timing case cover to cylinder head bolts (arrows).
NOTE-
Photo shows timing chain guide in place; it should first be re-
moved as described previously.
Remove crankshaft locking tool
(BMW special tool 11 2 300).
Using the crankshaft vibration damper bolt, turn engine op-
posite of normal direction of rotation (counterclocltwise as
viewed from the front) approximately 30". This prevents ac-
cidental contact between valves and pistons during installa-
tion.

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Cylinder Head Removal -- and lnstallati~i
4 Cylinder head bolt loosening sequence.
- Using BMW special tool 11 2 250 or an equivalent tool, loos-
en cylinder head bolts in sequence. Discard head bolts.
- Separate the cylinder head from the block and remove head.
Evaluate head as described in
116 Cylinder Head and Val-
vetrain.
Cylinder head, installing, M52 engine
If the camshafts were removed and installed while the cylin-
der head was off, a minimum waiting time is required after in-
stalling the camshafts. When the camshafts are removed, the
hydraulic lifters can expand. This expansion can cause in-
creased valve lift when the camshafts are bolted down, result-
ing in open valves.
Camshaft installation waiting times
68" F (20" C) and higher 4 minutes
50.68' F (1 0-20" C) 11 minutes
32-50' F (0-1 0" C) 30 minutes
- Clean cylinder head and gasket surfaces of cylinder block
and all timing chain covers.
CAUTION-
Do not use a metal scraper or wire brush to clean the alumi-
num cylinder head orpistons. If necessary, use a hard wood-
en orplastic scraper. Also available are abrasive discs to be
used in conjunction with an electric drill. Be sure to use the
correct disc for the type of metal being cleaned.
- Remove all debris and fluids from bolt holes and clean with a
thread chaser.
- Check gasket surface of cylinder head and cylinder block for
warpage using a straight edge.
NOTE-
If the cylinder head has been machined, a special 0.3 mm
thicker gasket should be installed. The thicker
gasket is avail-
able from an authorized
BMW dealer.

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--
Cylinder Head Removal and Installation
NOTE-
BMW special tool 11 4 220 is an adjustable primary chain
tensioner and simulates the function of the hydraulic
tensioner.
- Check that elongated holes in primary sprocket are now cen-
tered to bolt holes in camshaft and chain is free of slack. If
not, reposition sprocket to chain and reinstall.
- lnstall secondary timing chain guide and secondary chain
tensioner. Tighten mounting bolts (tensioner remains locked
down for now using
BMW special tool 11 3 292).
- Install cylinder identification trigger plate to front of intake
camshaft with studs.
- Install spacer to front of intake camshaft.
- Install secondary chain sprockets and chain as an assembly
so that arrows on sprockets are pointing up. Center mounting
holes in sprockets to bolt holes in camshafts.
4 lnstall thrust washers and diaphragm spring to intake cam
sprocket.
I 2hm thrust washer I
- Install shim and torx bolts to exhaust camshaft. Tighten fin-
ger tight; do not torque down.
- Tighten intake sprocket nuts.
CA UTIOG
Hold the camshaft stationary (at hex on camshaft) when loos-
enino or tiahtenino sorocket mounting bolts and studs.
Tightening torque
Intake s~rocket nuts to studs 10 +l Nm (89 +9 in-lb)
- Turn crankshaft approx. 30" in direction of rotation to bring
engine to TDC. Lock crankshaft in TDC position with BMW
special tool
11 2 300.
CAUTION-
The camshafts andcranlshaft must be lockedin the TDCpo-
sition using BMW special tools 11 2 300 and 11 3 240. If the
camshafts and cranl(shaft are not at TDC, the valves can
contact the pistons.

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Cylinder Head Removal and Installation I
Remove cylinder head cover mounting studs (arrows) from
center of cylinder head.
- Remove crankshaft loclting tool from transmission bell hous-
Ing.
Lift primary chain and hold under tension, then rotate engine
at vibration damper in opposite direction of normal rotation
(counterclocltwise) approximately 30".
CAUTION-
By turning crankshait3O0, pistons are movedaway from top
dead center, to prevent possible valve interference to pistons
during camshaft servicing.
- Remove camshaft loclting tools (BMW special tool set 11 3
240) from rear of cylinder head.
4 Remove camshaft bearing cap 1 on intake camshaft.
4 Fit BMW special tools 11 3 260 (A) and 11 3 270 (B) to cyl-
inder head and screw long bolts (arrows) into spark plug
threads. Tensioning pins on tool will align with the bearing
caps on the
intake camshaft.
CAUJION-
Do not over torque bolts into sparkplug holes.

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. - -- -
Cylinder Head Removal and Installation --
Remove bolts (arrows) holding timing chain cover to cylinder
head. (Photo shows camshafts and camshaft bearing caps in
place).
4 Using BMW special tool 11 2 250 or equivalent, loosen cylin-
der head bolts in several stages, in sequence shown. Discard
head bolts.
NOJE-
BMW special tool 11 2 250 is a thin-walled Torx El2 socket
with an extended reach. The cylinder head bolts are re-
cessed into the head below the
camshaft towers with little
working space.
- Lift off cylinder head. Refer to 116 Cylinder Head and Val-
vetrain for cylinder head reconditioning information.
Cylinder head, installing, M52 TU and M54
engines
Clean cylinder head and gasket surfaces of cylinder bloclc
and all timing chain covers.
CAUTION- Remove foreign matter and liquid from bolt holes. Trapped oil
or coolant in bolt holes can cause damage to
blocl~,
CAUJION-
Do not use a metal scraper or wire brush to clean the alumi-
num cylinder head or pistons. If necessary, use a hard wood-
en orplastic scraper. Also available are abrasive discs to be
used in conjunction with an electric drill. Be sure to use the
correct disc for the type of metal being cleaned.
Evaluate cylinder head as shown in
116 Cylinder Head and
Valvetrain.
NOTE- If the cylinder head has been machined, a special 0.3
mm
(0.01 1 in.) thicker gasket should be installed. The thicker
gasket is available from an authorized
BMW dealer and
should be marked accordingly
Cylinder head and valve specifications are covered in 116
Cylinder Head and Valvetrain.

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11 3-40
I Cylinder Head Removal and Installation
Lubricate camshafts, camshaft carriers, bearing caps, hy-
draulic lifters, friction washers, splined shafts and spline hubs
with assembly lubricant before installation.
4 Check that two cylinder head aligning sleeves (arrows) are
correctly positioned in block and are not damaged.
- Apply elastic sealing compound Three Bond 1209 8 to cor-
ner joints on cylinder block to timing chain cover.
- Place new cylinder head gasket on cylinder block.
NOTE-
The word "OBEN" or "TOP printed on the gasket, should
face up. The cylinder headgaslet will fit correctly in only one
orientation.
- Set cylinder head in position, guiding primary chain through
cylinder head opening.
CAUJION-
Make sure the crankshaft, which had been rotated approxi-
mately 30" opposite the direction of engine rotation from
TDC, is still in thatposition before lowering the cylinder head
into position. All pistons must be out of TDC position to pre-
vent
valve/piston interference when the camshafts are in-
stalled.
- Lightly lubricate new cylinder head bolts and washers with
oil. Install bolts and washers finger tight. Install cylinder head
to lower timing chain cover bolts finger tight.
NOJE-
Cylinder head bolts should not be reused. They are
stretch-type bolts and must be replaced whenever loos-
ened.
* Aluminum cylinder blocls use different length cylinder
head bolts and torque values than cast iron blocks.
Check that all washers for
Nle head bolts are in place be-
fore installing the bolts. Some of the washers may be
staked to the cylinder head.
I 12 10 4 2 6 8 141 Tighten cylinder head bolts in correct sequence (1-14)
CA U TIOW-
The bolts should be tightened in three stages as listed below
The final stages require the use of a BMW special tool
11 2
110 or a suitable protractor to tighten the bolts to a specified
torque angle.

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.-
Cylinder Head Removal and Installation
4 Rotate camshafts until intake and exhaust lobes for cylinder
1 face each other (arrows).
CAUTION-
Be sure that cranlcshaft is stillpositioned at least 30" away
from
TDC.
- 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 cylin-
der head over intake camshaft and screw long bolts (arrows)
into spark plug threads.
CAUTIOI\C
Do not overtighten bolts in 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 ft-lb)
Release tension on eccentric
shaft and remove BMW special
tools
11 3 2601270.
Repeat procedure for exhaust camshaft.
CAUTION-
After the camshafts are installed, a minimum waiting time is
required for the hydraulic lifters to 'bleed down" before bring-
ing the crankshaft andpiston back to top
deadcenter. When
the camshafts are removed, the hydraulic lifters can expand.
This expansion can cause increased valve lift when the cam-
shafts are bolted down, possibly resulting in piston interfer-
ence.
Crankshaft
I valve timing waiting times
68.F (20°C) and higher 4 minutes
50-68"F(10-20°C) 11 minutes
32-5O0F(O-10°C) 30 minutes