1999 BMW 525i Workshop Manual

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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

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11 3-44
I Cylinder Head Removal and Installation
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
4 In necessary, turn camshaft slightly so that special tools are
squarely seated on cylinder head.
4 Lift timing chain and hold under tension.

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Cylinder Head Removal and Installation
4 While maintaining tension on timing chain, rotate crankshaft
at vibration damper from
30" before TDC in direction of rota-
tion (clockwise) until number
1 cylinder is at TDC position
with line between the
OIT (arrow) on front pulley lined up
with boss on lower timing chain cover.

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1 13-46
Cylinder Head Removal and Installation
Double
VANOS Timing
Chain Components
1. Impulse wheel mounting nut
2. Exhaust camshaft impulse
wheel
3. Spring plate, exhaust
4. Thrust spacer (T
= 3.5 mm)
5. Splined shaft
6. Torx screw
7. Exhaust camshaft secondary
sprocket
8. Secondary timing chain
9. Splined sleeve
10. Primary sprocket
11. Threaded locating stud
12. Secondary chain tensioner
13. Secondary chain lower guide
14. Sprocket mounting nut
15. Spring plate, intake
16. Splined shaft
17. lntakecamshaft sprocket
18. Locating stud
19. Thrust spacer
20. Intake camshaft impulse wheel
Double VANOS timing chain components,
installing,
M52 TU and M54 engines -
4 Slide impulse wheel on intake camshaft, aligning boss with
raised portion on camshaft
(arrow).

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Cylinder Head Removal - an-]
Fit thrust spacer (A) to intake camshaft (B) and tighten down
with threaded locating studs. Place longer threaded end of
studs into camshaft
(arrows).
Tightening torque
Impulse
wheel studs to intake camshaft) 20 Nm (15 ft-lb)
Fit primary sprocket to primary timing chain and install on ex-
haust camshaft so that pointer on sprocket
(arrow) lines up
with cylinder head sealing surface.
4 Insert BMW special tool 11 4 220 into timing chain tensioner
bore and bring center spindle into contact with tensioning rail.
Tighten until slack is removed, but do not pretension timing
chain.
NOTE-
BMW special tool 11 4 220 is an adjustable primary chain
tensioner and simulates the function of the tensioner.
- Rechecic arrow on primary sprocket is aligned with upper
edge of cylinder head. Reposition sprocket if necessary.
Insert and tighten down threaded locating studs
(arrows) in
end of exhaust camshaft. Note installed position of studs.
Tightening torques Exhaust camshaft locating stud
20 Nm (15 ft-lb)

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I Cvlinder Head Removal and Installation
4 Install secondary chain tensioner on cylinder head (arrows).
Keep tensioner compressed using BMW special tool 11 3
291 or suitable pin.
< Install exhaust camshaft splined sleeve. Confirm that gap in
sleeve splines aligns with corresponding gap in
camshaft
splines (arrows).
Slide splined shaft onto exhaust camshaft. Be sure that locat-
ing tooth of shaft fits into spline gaps of camshaft and splined
sleeve
(arrows).
- Push splined shaft in further to rotate splined sleeve until the
three threaded holes in primary chain sprocket are centered
in the small slots of the splined sleeve.
4 Place intake and exhaust sprockets in BMW special tool 11 6
180. Position spline gap on intake sprocket (arrow) as shown
and place secondary chain on sprockets.

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-7 Cylinder Head Removal and lnstallat~on -- -- - -
Remove chain and sprockets from tool and slide sprockets
on camshafts. Confirm that gap in intake sprocket splines
lines up with corresponding gap in camshaft splines (arrow).
CAUTIOI\C
Do not alter position of sprockets with respect to chain when
removing
from special tool 11 6 180.
< Align locating tooth of splined shaft with gaps on camshaft
and sprocket. Slide splined shaft onto intake camshaft until
approx.
1 mm (0.04 in) of splines (arrows) are visible.
4 Install intake camshafl spring plate so that FRONT mark is
visible. Install mounting nuts (arrows) finger tight.
Insert sprocket mounting bolts (arrows) on exhaust side
camshaft assembly.
Initially tighten to approx.
5 Nm (44 in-lb) and then back off
by half a turn.

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I Cylinder Head Removal and lnstallatio~ - I
4 Fit thrust spacer (A) on exhaust camshaft.
4 Install spring plate (A) to exhaust camshaft. Malte sure that
(F) mark is visible.
NOTE-
If Fmark is no longer visible, install spring plate as shown in
inset.
4 Install exhaust camshaft impulse wheel, aligning pointer (B)
with top edge of cylinder head (A). Install mounting nuts (ar-
rows) finger tight.