Checking Valve Seat Wear Limit - Porsche 928 Workshop Manual

928
Engine/Cylinder Head, Valves
15
a
CHECKING VALVE SEAT WEAR LIMIT
Note:
Distinguishing feature, cylinder
2.Use the valve to be installed and
head
measure from the end of the valve
stem to the contact face of the
valve spring stop in the
'85/'86 models
'87 models onward
cylinder head.
M 28.43/44/45/46
M 28.41/42
Bearing bridge
attachment M 6
M8
0
Exhaust manifold
attachment,
:-bolt flange
3-bolt flange
l.The valve seats of the
4-valve-per-cylinder heads can be
machined. Do not machine past the
wear limit, as otherwise the
function of the hydraulic valve
tappets is no longer assured.
Size worn
Intake
Exhaust
3.While measuring, hold the valve
valve
valve
firmly against the valve seat.
'85/'86 mod.
a
'87 mod.
Printed in Germany-XIX,1987 Checking Valve Seat Wear Limit 15 - 113