Camshaft, Lifters and Push Rods: Service and Repair

Valve Gear

(Cylinder head removed, fitted in fixture, part no. 83 93 795)

To remove





IMPORTANT: The cylindrical surfaces round the valve springs are sealing surfaces for the tappets and must not be scratched or scored. Therefore, fit protective collars, part no. 83 93 746, round the tappet cylinders.

1. Remove the camshaft bearing caps. It is important to finish removal of the bearing caps with the one where the tappets are under load. Lift out the camshafts.
2. Remove the tappets and place them in the valve stand, part no. 83 93 787.
3. Fit the protective collars, part no. 83 93 746.





4. Press down the valve heads with the valve spring compressor, part no. 83 95 246, and remove the collet.
5. Lift out the spring discs and valve spring. Do not forget the washer.
6. Remove the valves and place them in the valve stand, part no. 83 93 787.

To fit





IMPORTANT: Defective valve stem seals must be replaced and the sealing surfaces with bearings lubricated before the valves are fitted. Make sure that the cylinder head is mounted in the fixture, part no. 83 93 795, so that the valves are not bent when the camshafts are tightened.

1. Fit the valves and springs.
2. Use valve spring compressor, part no. 83 95 246, to fit the spring discs and collets.
3. Place the clearance gauge, part no. 83 93 753, across two of the camshaft bearing seats with the depth gauge against the end of the valve stem.
4. Check that the maximum gauge depth of 20.5 mm actually reaches down to the end of the valve stem (noticed by the valve clearance gauge not bottoming against the bearing seat closest to the depth gauge).
5. Then, check that the minimum gauge depth of 19.5 mm does not reach down to the end of the valve stem. The correct valve clearance is between the minimum and maximum gauge depths. If the clearance is less than the minimum, the valve stem must be shortened and if it is greater than the maximum, the valve seat must be reground.





6. Remove the protective sleeves and fit the valve tappets.
7. Fit the camshafts and bearing caps, start where cams are pointing down and acting on the tappets. The bearing caps are marked 1-5 for the intake side and 6-10 for the exhaust side.
Tightening torque: 15 Nm (11 ft. lbs.)

IMPORTANT: The black bolts have an oilway and should be fitted on the spark plug side.

8. Line up the marks on the camshafts with their timing marks.

Valve-gear timing





When the pistons in cylinders no. 1 and no. 4 are at "top dead center", the marking on the crankshaft pulley should be in line with the setting mark on the timing cover. Alternatively, the 0°-marking of the flywheel/drive plate should be in line with the marking on the end plate.
When the camshafts are in line with their respective timing marks, the intake and exhaust valves in cylinder 1 are closed.
As the valves open, they extend beyond the face of the cylinder head and into the zone where the pistons change direction. If the setting of the crankshaft and valve gear is incorrect, the valves and other vital parts in the engine will be damaged.