Valve Seat - Checking Depth

91porsche01

January 22, 1991



Model Group

911 C2/C4 1

Part Identifier Number

1570 9102


Subject:
Valve Seat Depth Checking


ATTENTION: Service Manager/Service Technician

Models Affected: 911 Carrera 2 and 911 Carrera 4

Concern: Checking valve seat depth

Figure 1:

Repair Information: Distance A (Figure 1), valve stem end to cylinder head contact surface for the valve spring retainer, should not exceed 45.5 +/- 0.3 mm after machining valve seats.


Measurement must be taken with valve spring, spring retainer, and shims removed. If distance exceeds the specified value with a used valve, measure again using a new valve. If distance still exceeds the specified value, replace the cylinder head.