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Valve Seats
Reconditioning
ACTUAL
SEATING
SURFACE
VALVE
SEAT
Renew the valve seats in the cylinder head using a
valve seat cutter.
NOTE: lf guides are worn (see page 6-26), replace
them {see page 6-27) before cutting the valve seats.
C a r e f u l l y c u t a 4 5 " s e a t , r e m o v i n g o n l y e n o u g h
material to ensure a smooth and concentric seat.
Bevel the upper edge of the seat with the 30. cutter
and the lower edge of the seat with the 60. cutter.
Check width of seat and adjust accordingly.
Make one more very light pass with the 45o cutter to
remove any possible burrs caused by the other cut-
rers.
V8lv6 S€at Width (lntake and Exhaustl:
Standard {New}: 1.25 - 1.55 mm {0.0/t{, - 0.061 in}
S€rvice Limit:
2.0 mm 10.08 in)
After resurfacing the seat, inspect for even valve
seating: Apply Prussian Blue compound to the valve
face. Insert the valve in its original location in the
head, then lift it and snap it closed against the seat
several times.
PRUSSIAN BLUE COMPOUNO
6-29
o .
The actual valve seating surface, as shown by the
blue compound, should be centered on the seat.
lf it is too high (closer to the valve stem), you
must make a second cut with the 60" cutter to
move it down, then one more cut with the 45"
cutter to restore seat width.
lf it is too low (closer to the valve edge), you
must make a second cut with the 30. cutter to
move at up, then one more cut with the 45. cutter
to restore seat width.
NOTE: The final cut should always be made with
the 45" cutter.
Insert intake and exhaust valves in the head and
measure valve stem installed height.
Intake Valve Stem Inst8lled Height:
Standard lN6wl: 40.765 - i11.235 mm
(1.6049 - 1.6234 in)
Servico Limiti
i01.,|85 mm (1.6333 in)
Exhaust Valv€ Stem Installed Height:
Standard {Newl: ,[2.765 - 4:1.235 mm
1 .
{1.68i}7 - 1.7022 inl
,(1.485 mm 11.7120 inl
Service Limit:
I_1
I
VALVE STEM
INSTAI-LED HEIGHT
8 .
l f v a l v e s t e m i n s t a l l e d h e i g h t i s o v e r t h e s e r v i c e
limit, replace valve and recheck. lf still over the ser-
vice limit, replace cylinder head; the valve seat in
the head is too deep.
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Troubleshooting
