2001 BMW 525i camshaft

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11 6-28
Cylinder Head and Valvetrain
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 stud
12. Secondary chain tensioner
13. Secondary chain lower guide
14. Sprocket mounting nut
15. Spring plate, intake
16. Splined shaft
17. Intake camshaft sprocket
18. Locating stud
19. Thrust spacer
20. lntake camshaft impulse wheel

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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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~ ~. --
Cylinder Head and Valvetrain .-
4 While maintaining tension on timing chain, rotate crankshaft
at vibration dampener from
30" before TDC in direction of ro-
tation (clockwise) until number
1 cylinder is at TDC position
with line between the OIT mark (arrow) on front pulley
aligned with boss on lower timing chain cover.
4 Secure crankshaft in TDC position with BMW special tool
11 2 300 (arrow).
Slide impulse wheel on intake camshaft, aligning boss with
raised portion on camshaft (arrow).
Fit thrust spacer
(A) to intalte camshaft and tighten down with
threaded locating studs (arrows). Place longer threaded por-
tion of studs into camshaft.
Tightening torque
Impulse wheel studs to intake camshaft (M7)
20 Nm (15 ft-lb)

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11 6-31
Cylinder Head and Valvetrain
< Install primary timing chain on timing chain sprocket and
place on exhaust 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.
- Recheck arrow on primary sprocket is aligned with upper
edge of cylinder head. Reposition sprocket if necessary.
4 Insert and tighten threaded locat~ng studs (arrows) in ex-
haust camshaft.
Tightening
torques
Exhaust camshaft locating stud 20 Nm (15 ft-lb)

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11 6-32
Cylinder Head and Valvetrain
4 Install secondary chain tensioner (arrows). Keep tensioner
compressed using
BMW special tool 11 3 292 or suitable pin.
4 Fit exhaust camshaft splined sleeve. Confirm that gap in
sleeve splines aligns with corresponding gap in carnshaft
splines
(arrows).
Slide splined shaft onto exhaust camshaft so that locating
tooth of shaft fits into spline gaps of camshaft and splined
sleeve
(arrows).
- Push splined shafl 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.

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Cylinder Head and valvetrain1
< 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
sprocitets.
< Remove chain and sprockets from tool and slide sprockets
on camshafts. Confirm that gap in intalte sprocket splines
lines up with corresponding gap in camshaft splines (arrow).
CAUTIOI\C
Do not alter position of sprockets with respect to chain when
removinq from saecial tool 11 6 180.
4 While aligning locating tooth of shaft with spline gaps on
camshaft and sprocket, slide spiined
shaft onto intalte carn-
shaft until approx. 1 mm (0.04 in.) of splines (arrows) are
visible.
4 lnstall intake camshaft spring plate so that FRONT mark is
visible. install mounting nuts (arrows) finger tight.

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/Cylinder Head and Valvetrain
4 Insert sprocket mounting bolts (arrows) on exhaust side
carnshaft assembly.
Initially tighten to approx.
5 Nrn (44 in-lb) and then back off
by half a turn.
4 Fit thrust spacer (A) on exhaust
camshaft.
4 Install spring plate (A) to exhaust camshaft. Make sure that
(F) mark is visible.
NOTE-
If F marlc is no longer visible, install spring plate as shown in
inset.

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. .
Cylinder Head and Valvetrain
Install exhaust camshaft impulse wheel, aligning pointer (B)
with top edge of cylinder head (A). Install mounting nuts (ar-
rows) finger tight.
4 Pull out exhaust camshaft splined shaft to stop.
- Press down on secondary chain tensioner and remove ten-
sioner lock-down tool.
Preload primary chain:
- Tighten adjusting screw on BMW special tool 11 4 220 to
specified torque.
Tightening torque Primary chain tensioner preload
0.7 Nm (6 in-lb)