Page 286 of 1002
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11 7-50
/Camshaft Timing Chain
Timing chains assembly
(M52 TU and M54 engines)
1. Impulse wheel mounting nut
2. Camshaft impulse wheel
(exh.)
3. Spring plate
4. Thrust spacer (T
= 3.5 mm)
5. Primary chain tensioner
6. Torx screw
7. Exhaust secondary sprocket
8. Splined shaft
9. Secondary timing chain
10. Splined sleeve
11. Primary sprocket
12. Threaded stud
13. Secondary chain tensioner
14. Sprocket mounting nut
15. Spring plate
16. Splined shaft
17. Intake camshaft sprocket
18. Secondary chain lower guide
19. Thrust spacer
20. Camshaft impulse wheel
(intake)
21. Chain tensioner rail
22. Crankshaft sprocket
23. Threaded stud
24. Primary chain
25. Threaded stud
26. Guide rail
27. Threaded stud
28. Woodruff key
Page 289 of 1002
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-
Camshaft Timing chain1
< Remove intake camshaft sprocket mounting nuts (arrows)
and remove spring plate (labelled
FRONT).
Remove tom screws from exhaust camshaft sprocket
(arrows).
Lift off exhaust and intake sprockets with secondary chain,
thrust spacer
(A) and splined shaft (B).
CAUTION-
Splined shafts for both intake and exhaust camshafts share
the same part
numbe,: Remove and mark used splined
shafts in order to reinstall in original locations.
4 Remove exhaust camshaft splined sleeve (A) and shaft (8).
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... -.
rpp- --- Camshaft Timing Chain1
Timing chains, installing
(M52 TU and M54 engines)
CAUTIOI\C
The procedure outlined below assumes that the camshaits
are lockedin the
TDC installation position with speciallocling
tools as shown earliel:
- inspect timing chain sprockets. Inspect guide rail and ten-
sioner rail for damage. Replace any part that is worn
or dam-
aged.
NOTE-
If any sprockets are being replaced due to wear, the chain
should also be replaced.
4 Primary timing chain assembly
1. Primary chain tensioner
2. Chain tensioner rail
3. Cranltshaft sprocket
4. Exhaust camshaft sprocket
5. Primary chain
6. Anchor bolt
7. Guide rail
8. Anchor bolt
9. Woodruff key
- Install primary timing chain to crankshaft sprocltet and hang
upper end from exhaust camshaft.
- If necessary, replace crankshaft radial seal in cover. See
Crankshaft oil seal, replacing (M52 TU and M54 engines).
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Camshaft Timing chain/
Fit top sprocltet to primary timing chain and install on exhaust
camshaft so that pointer (arrow) on sprocltet lines up with
cylinder head sealing surface.
Position sprocket so that chain slack is on tensioner rail side.
4 Insert BMW special tool 11 4 220 in cylinder head and screw
in adjustment screw
by hand just until it contacts tensioning
rail and chain slack is removed.
NOTE-
BMW special tool 71 4 220 is an adjustable primary chain
tensioner that simulates the function of the tensioner.
- Make sure arrow on top primary sprocket is still lined up with
upper edge of cylinder head. Reposition sprocket if neces-
sary.
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11 7-60
Camshaft Timing Chain
< Install and tighten down threaded locating studs (arrows) in
end of exhaust camshaft.
Tightening torque Exhaust camshaft locating
stud 20 Nrn (15 ft-lb)
4 Install secondary chain tensioner on cylinder head.
- Make sure tensioner is locked in compressed position as
described earlier.
Fit exhaust camshaft splined sleeve, aligning gap in sleeve
splines with corresponding gap on
camshaft splines
(arrows).
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- Camshaft Timing chain]
< Slide splined shaft onto exhaust camshaft, aligning larger
tooth with corresponding gap of splined sleeve (arrows).
Slide splined shaft in further until
3 small or elongated slots
in splined sleeve are centered to
3 threaded holes in
sprocket.
4 Place intake and exhaust sprocltets in BMW special tool 11 6
180. Position spline gap on intalte sprocket (arrow) as shown
and place secondary chain on sprocltets.
< Carefully remove chain and sprockets from tool and slide
onto camshafts. Align gap in
intalte sprocket splines with cor-
responding gap in camshaft splines (arrow).
CAUTION-
Do not alterposltion ofsprocl(ets with respect to chain when
removing from
specfa1 tool 1 1 6 180.
4 Slide splined shaft onto intake camshaft until approx. 1 mm
(0.04 in.) of splines can still be seen.
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Camshaft Timing chain1
4 lnstall spring plate (A) to exhaust camshaft. Make sure that
F mark is visible.
NOTE-
If F mark is no longer visible, install spring plate as shown
Install exhaust camshaft impulse wheel, aligning
mark (B)
with top edge of cylinder head (A). Install mounting nuts (ar-
rows)
finger tight.
4 Pull out exhaust splined shaft until it stops
- Press down on secondary chain tensioner and remove ten-
sioner lock-down tool.
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Camshaft Timing chain1
4 Remove oil lines from camshaft supports (arrows).
- Remove radiator cooling fan and fan shroud. See 170 Radi-
ator and Cooling System.
NOTE-
The radiator cooling fan nut (32 mm wrench) has left-hand
threads.
- Remove engine drive belts alternator and AlC compressor.
See
020 Maintenance.
4 Remove vibration damper bolts (arrows) and remove
damper.
4 Mount BMW special tool 11 2 450 to crankshaft hub while
aligning damper locator pin with hole (arrow) in special tool.
CAUTION-
Crankshaft center bolt is torqued to 410 Nm (300 ft-lb) use
BMWspecial tool I I 2 450 to secure crankshaft when remov-
ing center bolt.
- Loosen and remove cranltshaff center bolt.