Checking And Machining Valve Seats - Porsche 928 Workshop Manual

15
Engine/Cylinder Head, Valves
928
CHECKING AND MACHINING VALVE SEATS (32-VALVE ENGINES)
Visual inspection
l.Check that valve seat is tight in
cylinder head.
2.Check contact pattern. If valve
does not contact entire area of
valve seat, the seat must be
machined slighty.
Machining
l.Valve seat may be machined with,
for example, a Neway valve
grinder or a Hunger valve-seat
machining tool.
2.Machine the valve seats with a
45" valve reseating tool.
Afterwards, machine the face to
the specified face width with a
60" reseating tool. It is no
longer necessary to finish with a
30" reseating tool.
Intake-valve face width
1.5 mm
Exhaust-valve face width
1.8 mrr
3.Valve reseating tools, e.g.
Neway 234 45"
Neway 213 60"
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15 - 114 Checking and Machining Valve Seats XIX,1987
- Printed in Germany