BMW 5251 Service Manual page 281

Camshaft Timing chain1
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With compressed air line connected, turn engine at least
twice in direction of rotation until cylinder 1 intake and ex-
haust camshaft lobes (arrows) face each other.
Do not rotate engine counterclockwise to reach the top dead
center position. Instead, complete another two complete ro-
Remove sealing plug from bore at bellhousing. Secure crank-
shaft in TDC position with BMW special tool 11 2 300 (ar-
row).
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Remove cylinder head cover studs at rear of cylinder head.
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Place BMW special tool 11 3 240 over camshafts ends and
measure clearance of tool to cylinder head surface.
NOTE-
I f the exhaust side of the tool (A) is not flush with the head,
adjust camshaft timing as described below.
Due to flexible sprocket design and VANOS control unit tol-
erances and play, the intake side of special tool 11 3 240
(B) may be up to 1 mm (0.04 in) above the surface of the
cylinder head. This is normal. Reassemble engine. Other-
wise, adjust camshaft timing as described below.
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Remove double VANOS control unit. See VANOS control
unit, removing (M52 TU and M54 engines).
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Press down on secondary chain tensionerand lock into place
using BMW special tool 11 3 292 or equivalent pin or drift.