Special tools required:
(cylinder bank 1 to 4)
Necessary preliminary tasks:
IMPORTANT: Screw (1) is a special screw and must not be replaced with a normal M8 screw.
Release screw (1).
Unclip oil line (3) from retainers (2) and remove.
Fig. 337: Identifying Retainer And Screw
Crank engine at central bolt in direction of rotation to firing TDC position of 1st cylinder.
NOTE: In firing TDC position, cam of exhaust camshaft at 1st cylinder points upwards at an angle.
Cam of inlet camshaft points downwards at an angle:
Fig. 338: Locating Cam Lobe Position
NOTE: Alignment hole for TDC position is at front on timing case cover.
Crank engine at central bolt and secure vibration damper with special tool 11 9 190 in firing TDC position of 1st cylinder.
Fig. 339: Identifying Special Tool (11 9 190)
IMPORTANT: When the engine is shut down, the inlet and exhaust adjustment unit 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 adjustment unit.
In order to avoid incorrect timing adjustment, it is essential to check the locking of the adjustment unit and if necessary perform locking by rotating the camshafts.
Checking locking of inlet adjustment unit in initial position:
Engage hexagon head of inlet camshaft and attempt to rotate inlet camshaft carefully against direction of rotation.
If there is no fixed connection between inlet camshaft and inlet adjustment unit, rotate inlet camshaft against direction of rotation as far as it will go.
The inlet adjustment unit is locked in the initial position when the inlet camshaft is non-positively connected to the inlet adjustment unit.
Fig. 340: Rotating Inlet Camshaft
Checking locking of exhaust adjustment unit in initial position: Engage hexagon head of exhaust camshaft and attempt to rotate exhaust camshaft carefully in direction of rotation.
If there is no fixed connection between exhaust camshaft and exhaust adjustment unit, rotate exhaust camshaft in direction of rotation as far as it will go.
The exhaust adjustment unit is locked in the initial position when the exhaust camshaft is non-positively connected to the exhaust adjustment unit.
Fig. 341: Rotating Exhaust Camshaft
IMPORTANT: If the inlet or exhaust adjustment unit of the camshafts "cannot" be locked as described, the adjustment unit is faulty and must be replaced.
Place special tool 11 9 461 on inlet camshaft and check timing.
NOTE: The timing is correctly adjusted when special tool 11 9 461 rests flat on the cylinder head or protrudes by up to 0.5 mm to the exhaust side.
Fig. 342: Identifying Special Tool (11 9 461)
Place special tool 11 9 462 on exhaust camshaft and check timing.
NOTE: The timing is correctly adjusted when special tool 11 9 462 rests flat on the cylinder head or protrudes by up to 0.5 mm to the exhaust side.
If necessary, adjust camshaft timing on right side.
Fig. 343: Identifying Special Tool (11 9 462)
Remove all special tools.
IMPORTANT: Screw (1) is a special screw and must not be replaced with a normal M8 screw.
Clip oil line (3) into retainers (2).
Insert screw (1) and tighten down.
Assemble engine.
Fig. 344: Identifying Retainer And Screw