1999 BMW 525i Workshop Manual

Downloaded from www.Manualslib.com manuals search engine
Cylinder Head and Valvetrain
4 Secure hydraulic lifters in lifter bores using BMW special tool
11 3 250, or remove lifters using a magnetic pick-up tool.
4 Remove camshaft bearing carrier from cylinder head.
CA UTION-
Camshaftbearing carriers must be reinstalledin their original
/ locations (E for ir;fal NOTE-
Do not let hydraulic lifters fall out as the camshaft carrier is
removed.
Hydraulic lifters should be stored in an upright position.
Used hydraulic lifters
must be replaced into original lifter
bores.
Camshafts and lifters, installing
(M52 Engine)
Lubricate camshafts, camshaft carriers, bearing caps, hy-
draulic liflers, friction washers, splined shafts and spline hubs
with assembly lubricant before installation.
Make sure
the cranltshaft, which had been rotated approxi-
mately
30" opposite the direction of engine rotation from
TDC, is still in thatposition before lowering the
camshaffs into
position. All pistons must be out of TDC position to prevent
valve/piston interference when the camshalts are installed.
Before installing camshaft carriers, examine bearing bores
(arrows) on hydraulic lifter bores for signs of wear.

Downloaded from www.Manualslib.com manuals search engine
116-18
Cylinder Head and Valvetrain
4 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 posi-
tions
2 and 7.
4 Install camshafts with number 1 cylinder camshaft lobes fac-
ing each other (arrows).
CAUTION-
A minimum waiting time is required for the hydraulic lifters to
'bleed down" after installing the camshafts into the cylinder
head, before bringing the pistons to TDC. When the cam-
shafts are removed, the hydraulic
lifers can expand. This ex-
pansion can cause increased valve lift when the camshafts
are bolted down, possibly resulting in piston interference.
Camshaft Installation waiting
times
68" F (20" C) or above 4 minutes
50-68' F (1 0-20°C) 11 minutes
32-50" F (0-1 0" C) 30 minutes

Downloaded from www.Manualslib.com manuals search engine
Cylinder Head and valvetrain1
- Remainder of installation is reverse of removal, noting the
following:
See
117 Camshaft Timing Chain for VANOS control unit
installation.
Tightening torques
Camshaft bearing caps
to cylinder head (M7) 15 Nm (1 1 ft-lb)
Cylinder head cover to cylinder head (M6) 10 Nm (89 in-lb)
Sparic plugs (M12) 23 Nm (17 ft-lb)
Camshaft and lifter, removal and
installation
(M52 TU and M54 engine)
Camshafts and lifters, removing
(M52 TU and M54 engine)
WARNING-
Allow engine fo cool before beginning this procedure.
- Disconnect negative (-) cable from battery.
CAUTION--
Prior to disconnecting the battea read the battery discon-
nection cautions in
001 General Cautions and Warnings.
Remove VANOS control unit. See 117 Camshaii Timing
Chain.
Remove primary timing chain tensioner (arrow).
CAUTION-
Primary timing chain tensioner is under spring pressure. 1

Downloaded from www.Manualslib.com manuals search engine
/Cylinder Head and Valvetrain
Press down on secondary chain tensionerand loclc into place
using
BMW special tool 11 3 292, or a thin drift or pin.
4 Remove exhaust camshaft impulse wheel mounting nuts
(arrows). Remove impulse wheel (A).
< Remove spring plate (A).
4 Remove intake camshaft sprocket mounting nuts (arrows)
and remove spring plate (labelled
FRONT).

Downloaded from www.Manualslib.com manuals search engine
I_
-.
Cylinder Head and Valvetrain
Remove torx
(arrows). screws
from
exhausl
: camshaft : sprocket
Lift off exhaust and intalte sprockets together with secondary
chain, thrust spacer
(A) from exhaust camshaft, and splined
shaft (B) from intake camshaft.
CAUTIOf+
Splined shafts share the same part number for both intake
and exhaust camshafts. Used splined shafts must be rein-
stalled in their
oriqinal locations.
Place intalte and exhaust sprockets in
BMW special tool 11 6
/ 180. Position spline gap on intake sprocket (arrow) as
shown.
4 Remove exhaust camshaft splined sleeve (A) and shaft (B).

Downloaded from www.Manualslib.com manuals search engine
11 6-22
Cylinder Head and Valvetrain
Remove secondary chain tensioner mounting bolts (arrows)
and remove tensioner with locking tool in place.
Remove primary chain sprocket mounting studs
(arrows) on
exhaust camshaft.
NOTE-
Counterhold camshafts when loosening.
Lifl primary chain sprocket off exhaust camshaft. Remove
sprocket from chain.

Downloaded from www.Manualslib.com manuals search engine
11 6-23
Cylinder Head and Valvetrain
Place timing
chain on end of exhaust camshaft
4 Do not remove end spline retaining screws from camshafts
(arrows).
CAUTION-
The end spline retaining screws precisely locate the end
splines to the camshafts. Do not loosen these screws.
Remove locating studs (arrows) from
intake camshaft. Lift
off intake
camshaft thrust spacer (A) and impulse wheel (B)
4 Remove cylinder head cover mounting studs (arrows) from
center of cylinder head.
- Remove crankshaft locking tool (BMW special tool 11 2 300)
from cranltcase.

Downloaded from www.Manualslib.com manuals search engine
..--.
I Cylinder Head and Valvetrain - I
4 Lift primary chain and hold under tension, rotate engine
against direction of rotation (counterclockwise) approximate-
ly 30".
To prevent damaging valves while
worlcing on camshafts, no
aistons should be in the TDC position.
- Remove BMW special tool set 1 I 3 240 from rear of cylinder
head.
Remove retaining nuts (arrows) and bearing cap
1 of intake
camshaft.
Intake camshaft bearing cap
1 is centered with adapter
sleeves. To avoid camshaft damage, it must be removed be-
fore anv other caos.
4 Fit BMW special tools 11 3 260 (A) and 11 3 270 (B) to cylin-
der head and screw long bolts (aiiows) into spark plug
threads. Tensioners will align with the bearing caps on the in-
take camshaft.
CA UTION--
Do not over torque bolts into spark plug holes. 1
4 Turn eccentric shaft of special tool to pretension intake carn-
shaft bearing caps. Remove nuts on remaining bearing caps.
- Slowly release tension on eccentric shaft and remove BMW
special tools. Remove bearing caps and set aside in order.
Remove camshaft and store safely.
CA U TIOW-
Camshaft bearing caps must be installed in their original lo-
cations.