911 Carrera Coupe F6-3164cc 3.2L (1984)
Valve: Technical Service Bulletins
Valve Seat - Checking Depth
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.