Vauxhall Workshop Service and Repair Manuals

Cylinder Head  

Exhaust Valves  

The disc surfaces of the exhaust valves for DTH engines are coated with an approx. 0.1 - 0.2 mm thick plasma layer to compensate for the high thermal stress.   The valves are identified with codes to prevent confusion on installation (1).

Valve identification:  

Engine	X 20 DTL	X 20 DTH, X 22 DTH
	Intake/exhaust valve	Intake valve	Exhaust valve
Standard size	GM	GM G	GM P
Oversize 0.075 mm	GM K1	GM GK1	GM PK1
Oversize 0.150 mm	GM K2	GM GK2	GM PK2