Removal

Removal
(Inlet Or Exhaust Side As Applicable)
The inlet or exhaust camshaft can be replaced in the vehicle.

Caution: Incorrect assembly/removal without special tools exposes the camshaft to the risk of preliminary damage or breakage. The valves may also be bent by contact with the piston crown. Comply without fail with the job instructions, recommended special tools and work sequence.

Removal of camshafts is described separately from installation.
The assembly sequence for removal and installation is different.

Remove VANOS adjustment unit. Service and Repair





Caution: Cylinder for chain tensioning piston is under spring pressure.

Unfasten cylinder for chain tensioning piston.





Press down secondary chain tensioner at top and lock with special tool 11 3 292.





Release nuts, remove sensor gear (1).





Remove plate spring (2).





Release nuts on inlet side and remove corrugated washer (7).





Unfasten screws.





Lift off exhaust and inlet chain wheels together with chain, friction washer (3) and toothed shaft (4).

Note:
The toothed shaft (4) is the same part for the exhaust and inlet sides.
Store used toothed shafts in order and reinstall on the same side only.





Remove toothed shaft (5) with toothed sleeve (6).





Unfasten screws. Remove secondary chain tensioner.





Release screw-in pin.





Feed chain wheel (1) towards front out of timing chain (2).





Note: Timing chain remains positioned over exhaust camshaft.





If necessary, release screw-in pin on inlet side.
Remove thrust washer.





Remove sensor gear.





Caution: Do "not" release these screws.





Unscrew studs.





Pull special tool 11 2 300 back until flywheel is no longer secured in position.





Caution: To prevent damaging valves when fitting the camshafts, no pistons should be in TDC position.

Lift timing chain and hold under tension.
Rotate engine against direction of rotation approx. 30° at central bolt.





Caution:
Bearing cap 1 of inlet camshaft is centered with adapter sleeves.
To prevent inlet camshaft from tilting in bearing strip, release nuts and remove bearing cap 1.





Fit special tool 11 3 260 to cylinder head and screw into spark plug threads in cylinders 1 and 4.





Turn the eccentric shaft to pre-tension the bearing caps.
Unfasten nuts on bearing cover.





Relieve tension on eccentric shaft and remove special tool 11 3 260.
Remove bearing covers and place to one side in orderly fashion. Remove camshaft.





Note:
If the cylinder head is then to be removed, remove complete bearing strip with bucket tappets.
Locate bucket tappets in bearing strip with special tool 11 3 250.
Lift out complete bearing strip with bucket tappet.

Note: Only re-use used bucket tappets in the same tappet bore.





Check bearing points on bucket tappets for signs of wear (scoring).





Bearing strips are marked "A" for exhaust side and "E" for inlet side.





Note centering dowels on retaining pins at bearing points 2 and 7.
Install bearing strips.