11 31 070 Checking Camshaft Timing on Left Side

11 31 070 Checking camshaft timing on left side (N74)

Special tools required:





Important!
The timing can only be checked with special tool 11 9 900.
The timing may be misinterpreted if it is checked without special tool 11 9 900.

Cylinders 7 - 12:

Necessary preliminary work:
^ Remove left cylinder head cover





^ Remove fan cowl with electric fan
^ Remove belt pulley for air conditioning system
^ Remove left chain tensioner





Mount special tool 11 9 900 at position of chain tensioner.

Preload hexagon socket screw with special tool 00 9 250 to 0.6 Nm.





Important!
When the engine is shut down, the inlet and exhaust camshaft adjuster is normally locked in its initial position.
The situation may arise in some individual cases where this initial position is not reached and the camshaft can continue to be rotated in the adjustment range of the adjuster.
In order to avoid incorrect timing adjustment, it is essential to check the locking of the adjuster and if necessary perform locking by rotating the camshafts.





Checking locking of inlet and exhaust adjustment units in initial position:

Gripping hexagon head (2) of camshafts with a fork wrench (1), carefully try to rotate camshafts against direction of rotation.

The inlet and exhaust adjustment units are locked in the initial position when the camshafts are non-positively connected to the adjustment units.





Important!
If the inlet or exhaust camshaft adjuster of the camshafts "can not" be locked as described, the adjuster is faulty and must be replaced.





Note:
If the camshafts are at the TDC firing position for cylinder 1, the labelling on the exhaust camshaft (1 and 2) can be read from above.

A = exhaust camshaft.

712 = cylinder 7 to 12.





With 1st cylinder in firing TDC position, cams of exhaust camshaft ( 1) of the 1st cylinder point inward at an angle (see arrow).





Note:
If the camshafts are at the TDC firing position for cylinder 1, the labelling on the intake camshaft (1 and 2) can be read from above.

E= intake camshaft.

712 = cylinder 7 to 12.





With 1st cylinder in firing TDC position, cams of intake camshaft (1) of the 1st cylinder point inward at an angle (see arrow).





Release screws (1).

Lay auxiliary water pump holder to one side.





Position special tool 11 8 570 with the mounting flats on the vibration damper at the TDC mark.

Secure special tool 11 8 570with a screw (1).





Crank engine at the central bolt in direction of engine rotation.

Use special tools 11 8 570 and 11 9 190 to insert the vibration damper in the upper bore hole.





The crankshaft is correctly positioned when the special tool 11 8 570 is locked with 11 9 190 in the groove (see arrow).

The crankshaft is locked in the Cylinder 1 firing TDC position.





Fit special tool 11 9 893 on intake camshaft and check timing adjustment.

Note:
Timing is correctly adjusted when special tool 11 9 893 rests without a gap on cylinder head.





Place special tool 11 9 893 on the exhaust camshaft and test timing adjustment.

Note:
Timing is correctly adjusted if special tool 11 9 893 rests on the cylinder head without any gaps.

If necessary, adjust camshaft timing on left side.





Remove all special tools.

Assemble engine.