Cylinder Head Assembly: Testing and Inspection

NOTE: Cylinder head and camshaft removed.

Check and adjust the valve clearance relative to the working range of the tappet.

The tolerances for checking valve clearance are 19.5 ± 0.05 mm minimum and 20.5 ± 0.05 mm maximum.

The valve clearance settings are 20.0 mm minimum and 20.4 mm maximum, with a nominal clearance of 20.2 mm.

The valve clearance is equivalent to the distance between the end of the valve stem and the camshaft bearing seat.

Before valve clearances can be checked, the camshafts and valve tappets must first be removed.

Check the valve clearances using gauge tool 83 93 753, or equivalent, as follows:
1. Place the measuring head across two of the camshaft bearing seats with the depth gauge against the end of the valve stem.
2. Check that the maximum gauge depth of 20.5 mm actually reaches down to the end of the valve stem (noticed by the measuring head not bottoming against the bearing seat closest to the depth gauge).
3. 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 deviates from the specified tolerances, adjustment must be made to the valve stem or the valve seat. If the clearance is less than the minimum (19.5 mm) the valve stem must be shortened and if it is greater than the maximum (20.5 mm) the valve seat must be reground. The nominal figure for adjusting the clearance of the valve is 20.2 mm.