Removal

(Intake or exhaust side as applicable)
The intake and exhaust camshafts can be changed in the vehicle

Caution: Incorrect removal/installation without help of fixture could damage or break the camshaft. Valves could also be bent through contact with the piston crowns. Always note installation instructions and use specified special tools, procedures, and sequences.

Removal
Removal of camshafts is described separately from installation.
Assembly sequence for removal and installation is different.
If necessary, remove VANOS adjustment unit.





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, thrust 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 only reinstall on the same side as before.





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 resting above exhaust camshaft.





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





Remove sensor gear.





Caution: Do "not" remove these screws.





Unscrew studs.





Pull back special tool 11 2 300 until flywheel is no longer located 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 counter-enginewise approx. 30° using the central screw.





Caution:
^ Bearing cover 1 on intake camshaft is centered on hollow dowels.
^ To prevent the inlet camshaft from tilting in the 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.
Tightening Torque, refer to Engine, Specifications, Mechanical.





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





Loosen 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: Worn bucket tappets may only be reused in the same tappet bore





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





The bearing strips are marked "A" for the exhaust side and "E" for the inlet side.





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