BMW 1989-1995 525i Service Manual page 132

117-12
CAMSHAFT TIMING CHAIN
I
@-.
20. Inspect the guide rail and tensioner rail for deep
grooves caused by chain contact. The rails can be re-
placed after removing the circlips from the mounting
pins. See Fig. 28. Always use new circlips.
811144
•
-
Fig . 26. Front oil pan mounting bolts
(arrows)
as viewed from below.
Fig. 27. Camshaft sprocket mounting bolts
(arrow s).
CAUTlON -
Do not rotate the crankshaft or the cams haft wh ile
the timing chain
is
removed. The pistons can con-
tact the open valves
V\o
@ .....
\ \
\
8 357.ENG.8
Fig . 28. Guide rail mounting circlips.
To install camshaft timing cha in (M30 engine) :
1.
Install the timing chain. gu iding it up throug h the guide
rails and cylinder head gasket. Make sure the chain is
properly engaged on the crankshaft sprocket.
2. Install a new crankshaft oil seal in the lower timing
chain cover and apply a light coat of engine oil to the
seal. Temporarily install the lower cover. Temporarily in-
stall the crankshaft wood ruff key together with the
crankshaft hublvibration damper. Check that both the
camshaft and the cranks haft are set at Top Dead Cen-
ter (TOC) as shown earlier in Fig. 25.
3. Install the camshaft sprocket with the chain to the cam-
shaft so that all chain slack is on the tensioner side of
the chain. Tighten the sprocket mounting bolts.
NOTE -
• If any of tile sprockets are being replaced due to wear.
the chain should also be replaced.
• If the crankshaft sprocket requires replacement. the
oil pan and the oil pump drive sprocket must be re-
moved
as
described in 119
Lubrication
System. The
crankshaft sprocket can be removed from the crank-
shaft using
a
puller. Prior to installing the replacement
sprocket. it must first be heated in an oil ba th to
a
maximum temperature of 390'F (200'C). At this tem-
perature. the sprocket can be driven onto the crank ·
shaft while aligning the woodruff keyway
Tightening Torque
• Camshaft sprocket
to camshaft 10
±
1 Nm (89
±
9 in-Ib)
4. Remove the hublvibration damper and the lower timing
chain cover.
CAMSHAFT TIMING CHAIN