11 31 573 Adjusting Camshaft Timing on Left Side

11 31 573 - Adjusting camshaft timing on left side (N73)





Special tools required:
- 11 9 190 11 9 190 Plug Mandrel
- 11 9 461 11 9 460 Gauge
- 11 9 462 11 9 460 Gauge
- 11 9 463 11 9 460 Gauge





Cylinders 7 to 12.

Necessary preliminary tasks:
- Remove intake air manifold Service and Repair.
- Remove left cylinder head cover [1][2]Removing and Installing/Sealing Left Cylinder Head Cover.
- Remove all spark plugs Service and Repair.
- Remove fan Service and Repair.
- Remove left timing case cover Removing and Installing Top Left Timing Case Cover (N73).





Crank engine at central bolt in direction of rotation to firing TDC position of 1st cylinder.

Secure vibration damper with special tool 11 9 190 11 9 190 Plug Mandrel in firing TDC position of 1st cylinder.





Cams on inlet and exhaust camshafts at 7th cylinder are inclined upwards.

See illustration.





Important!
Screw (1) must not be replaced by an M8 screw (special screw).

Release screw (1).

Unclip oil line (3) from retainer (2) and remove.





Important!
The adjustment units are locked in an initial position when the engine is switched off.

In individual cases this initial position is not achieved and the camshaft remains rotatable in the VANOS adjustment range.

In order to avoid incorrect timing adjustment, it is necessary to check the locking of the VANOS and if necessary perform locking by rotating the camshafts.





Locking check (inlet):

Engage hexagon head of camshaft at front and rotate inlet camshaft carefully against direction of rotation.

The inlet VANOS is locked in the initial position when the inlet camshaft is non-positively connected to the inlet VANOS.





Locking check (exhaust):

Engage hexagon head of camshaft at front and rotate exhaust camshaft carefully in direction of rotation.

The exhaust VANOS is locked in the initial position when the exhaust camshaft is non-positively connected to the exhaust VANOS.





Important!
If the inlet and exhaust VANOS of the camshafts "cannot" be locked as described, the VANOS is faulty and must be replaced.





Release screws of inlet and exhaust VANOS.

Note:
When slackening screws, grip camshafts at hexagon head.





Special tool 11 9 461 11 9 460 Gauge for securing inlet camshaft.

Special tool 11 9 462 11 9 460 Gauge for securing exhaust camshaft.

Special tool 11 9 463 11 9 460 Gauge (holder with screw).





Place special tool 11 9 461 11 9 460 Gauge on inlet camshaft and align inlet camshaft so that special tool 11 9 461 11 9 460 Gauge rests flat on cylinder head.

Insert special tool 11 9 463 11 9 460 Gauge in thread of oil line and tighten down by hand with screw (1).





Tighten down screw (1) of inlet VANOS.

Installation:
Replace screw (1).

Tightening torque 11 36 16AZ 11 36 Variable Camshaft Control VANOS.

Note:
When tightening down screw (1), grip camshaft at hexagon head.

Remove special tool 11 9 461 11 9 460 Gauge.





Place special tool 11 9 462 11 9 460 Gauge on exhaust camshaft and align exhaust camshaft so that special tool 11 9 462 11 9 460 Gauge rests flat on cylinder head.

Insert special tool 11 9 463 11 9 460 Gauge in thread of oil line and tighten down by hand with screw (1).





Tighten down screw (2) of exhaust VANOS.

Installation:
Replace screw (2).

Tightening torque 11 36 16AZ 11 36 Variable Camshaft Control VANOS.

Note:
When tightening down screw (2), grip camshaft at hexagon head.

Remove special tool 11 9 462 11 9 460 Gauge.





Remove special tool 11 9 190 11 9 190 Plug Mandrel.

Crank engine at central bolt twice in direction of rotation until engine returns to firing TDC position of 1st cylinder.

Secure engine again with special tool 11 9 190 11 9 190 Plug Mandrel.

Check camshaft adjustments.





Note:
The timing is correctly adjusted when special tools 11 9 461 11 9 460 Gauge and 11 9 462 11 9 460 Gauge rest flat on the cylinder head or protrude by up to 0.5 mm to the exhaust side.

Remove all special tools.

Assemble engine.