BMW 5251 Service Manual page 203

--
-
. .-
-,
Cylinder Head and Valvetrain
4
Rotate camshafts so that intalte and exhaust lobes for cylin-
der 1 face each other (arrows).
CAUJION-
A minimum waiting time is required for the hydraulic lifters to
'bleed down"after installing the camshafts into the cylinder
head, before bringing the piston to TDC. When the camshafts
are removed, the hydraulic lifters can expand. This expan-
sion can cause increased valve lift when the camshafts are
bolted down, possibly resulting in piston interference.
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 cylinder
head over intalte camshaft and screw long bolts (arrows)
into spark plug threads.
CA UTION-
Do not overtighten bolts into 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 it-ib)
-
Release tension on eccentric shaft and remove BMW special
tools 11 3 2601270.
-
Repeat procedure for exhaust camshaft.
NOTE-
Observe waiting time for lifter bleed down before continuing
with camshaff installation.
Crankshaft I
valve
timing waiting times
68°F (20°C) and higher
5
minutes
50-6S°F(10-20°C) 15 minutes
32-50DF(O-10°C) 30 minutes