Exhaust Valves/Stem Seals - Seized
Number8909
Group
1
Model
944 Turbo
Part Identifier
1562/63
June 16, 1989
Subject:
Modified Exhaust Valves and Stem Seals
Prolonged high speed operation has caused seizing of exhaust valves in their guides in some countries other than the U.S. To reduce the possibility of this occurring, exhaust valves with a conical stem (0.01 mm) and modified valve stem seals are installed in all 1988 model 944 Turbo S and 1989 model 944 Turbos including those for the U.S.
47 J 00529 - Exhaust valves
47 J 00777 - Valve stem seals
The new exhaust valve can be identified by PN 951 105 416 07 die stamped on the valve stem end. (Fig. 1)
The new version valve stem seal PN 951 104 195 01 can be recognized by a 45 degree chamfer on the sealing lip. (Fig. 2)
Repair Information
If, upon inspection, the hydraulic valve lifter is found to be disassembled, the exhaust valve may have seized. If it is suspected that a valve may have seized, the following parts must be replaced:
- exhaust valve
- valve stem seal
- hydraulic lifter
- valve spring set
- upper spring retainer
- valve keepers
The new version parts may be used for repairs, on 1988 Turbo S and 1989 Turbo only Old type exhaust valves and stem seals may be used in earlier model engines until stock is depleted. Afterwards, new version parts may be used to repair older engines.
New and former version stem seals can be used on old type exhaust valves. However, old type stem seals may NOT be used together with new version exhaust valves.