BMW 5251 Service Manual page 113

I
Cylinder Head Removal and Installation
I
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Use BMW tool 11 2 110 or torque angle gauge to tighten cyl-
inder head bolts in sequence to stage 2 and 3.
Tightening torques
Cylinder head to cast iron bloclc
Staoe
1
staie 2
Stage
3
Cyllnder head
to
aiumlnum block
Stage
1
40 Nm
(30
it-lb)
Stage
2
+90°
Staoe
3
-80"
-
Tighten cylinder head-to-lower timing chain cover bolts.
Tightening torques
cylinderhead
to
lower timing chain cover 10 Nm
(89
in-lb)
-
Inspect secondary chain guide rail and tensioner rail for
grooves caused by chain contact. Replace any part that is
worn.
NOTE-
Inspect timing chain sprocl(ets. Sprockets that have worn
or missing teeth should be replaced.
*
If any of the sprockets are being replaced due to wear, the
chain should also be replaced.
If the crankshaft sproclet requir?s replacement, the oil
pump drive sprocket and chain must be removed as de-
scribed under 119 Lubrication System.
The procedure outlined below assumes that the camshafts
and the cranl(shaft are locledin the TDCposition with special
4
Mount primary timing chain sprocltet to primary chain so that
arrow on sprocket faces up. Mount sprocket to camshaft so
that tapped holes in camshaft are on left side of elongated
holes
i n
sprocltet
Install BMW special tool 1 I 4 220 into primary timing chain
tensioner sleeve. Thread center spindle in finger tight until
slack is removed from chain.