Removal and Replacement

CAUTION: If the camshaft is renewed, the rocker arms must also be renewed.

Inductively hardened camshafts must only be used with hard chrome-plated rocker arms (standard up to February 1989). Chilled cast camshafts may only be used with rocker arms with carbide metal coating (standard as from March 1989).
If bearing fretting or severe scoring exists, the camshaft bearings can be drilled open by 0.5 mm (0.020 in) in the cylinder head or in the rocker arm bearing brackets and a camshaft with oversized bearing journals installed.
After damage to a cam (e. g. worn cams), all the affected timing parts (hydraulic elements, valves, valve springs, valve plates and valve wedges) should be checked for signs of damage.
If individual rocker arm bearing brackets are renewed, all the bearing brackets must be tightened to specification and the camshaft checked to ensure that it moves freely.

REMOVAL

Setting TDC:

1. Set piston of No. 1 cylinder to TDC (arrow).
2. Remove front cover at the top, Service and Repair
3. Remove chain tensioner, Timing Chain Tensioner.

Camshaft Alignment:

4. Mark position of camshaft gear relative to camshaft. This is done by applying colored marking next to the locating pin (20) on the camshaft gear.

CAUTION: If the camshaft gear is renewed, the colored marking must be applied to the corresponding point on the new camshaft gear. The camshaft gear with 3 oblong holes (1st version) should be renewed if performing repairs with the camshaft gear 2nd version with 3 holes e 6 mm. The camshaft gear 2nd version can be used when performing repairs in place of the camshaft gear 3rd version with 3 7 mm holes. In this case the 3 holes should be widened from 6 mm to 7 mm. The timing can be set by turning or changing the side of the camshaft gear on the camshaft.

Cam Gear Bolts:

5. Unscrew bolts (16). Tightening torque: Hex. socket bolts M6 11 Nm (8 ft lbs), Torx bolts M7 16 Nm (12 ft lbs).
6. Pull off camshaft gear (19) by hand.

Cam Oiling Pipe:

7. Unscrew bolts (40, 43). Take off oil pipe (42).

CAUTION: The shaped edge of the oil spray holes on the oil pipe must not be misshaped otherwise this will affect the spray direction. The oil pipe (42) for lubricating the camshaft is attached additionally with a retaining plate (41) and a bolt (40) without washer on the 3rd rocker arm bearing bracket at the rear hole (inlet manifold side).

Oil Pipe Versions:

8. Check whether 1st or 2nd version of the oil pipe is installed.

Rocker Arm Bearing Bracket:

9. Unscrew bolts (44) in such a way that the rocker arm bearing bracket (605) is not tensioned, tightening torque 21 Nm (15.5 ft lbs).

CAUTION: The rocker arm bearing brackets must be installed again at the same point and at the same attitude. Use rocker arm 1st version with 3 mm wide reinforcing rib only with camshafts which are not chill cast. Use rocker arm 2nd version with 1.5 mm wide reinforcing rib only with chilled cast camshaft. The 2nd version of rocker arms have soldered-on carbide metal running surfaces.

Rocker Arms:

10. Remove all rocker arm bearing brackets.(Slacken tight rocker arm bearing brackets with light blows from a plastic headed hammer).

NOTE: When taking off the rocker arm bearing brackets, the ball sockets (53) may catch on the hydraulic valve clearance compensating elements.

11. Take off ball sockets (53).

CAUTION: The ball sockets must be installed again at the same point.

Camshaft Removal:

12. Lift out camshaft (26).

NOTE: When lifting out, pay attention to the thrust washer at the front (axial mounting).

13. Oil camshaft bearing journals.

Camshaft Positioning Hole:

14. With No. 1 cylinder in TDC position, insert camshaft so that the pin (22) or the positioning hole (21) is facing up the way.
15. Oil cam and rocker arm sliding surfaces.
16. Fit on all rocker arm bearing brackets. Screw in all bolts by hand and tighten evenly, tightening torque 21 Nm (15.5 ft lbs).





17. Pin (22) or positioning hole on 1st camshaft flange must be aligned with the marking (517) when No. 1 cylinder is in the TDC position.
18. Check the oil supply (spray direction) of the camshaft at idling speed.

CAUTION: If damage to a camshaft has been caused by a lack of oil resulting from a loose oil nozzle return lock without stop collar, an oil nozzle return lock with stop collar must be installed.