Valve Seats; Recondltioning - Honda Prelude 1993 Service Manual

Valve Seats
Reconditioning
Renew the valve seats in the cylinder head using a
valve seat cutter.
NOTE: lf guides are worn (page 6-98), replace them
(page 6-991 before cutting the valve seats.
Carefully cut a 45o seat, removing only enough
material to ensure a smooth and concentric seat.
Bevel the upper edge of the seat with the 30" cut-
ter and the lower edge of the seat with the 60o cut-
ter. Check width of seat and adjust accordingly.
Mak€ one mor€ very light pass with the 45o cutter
to remove any possible burrs caused bv the other
cutters.
Valvo Soat Width (lntake and exhaustl:
Standard (N6w): 1.25- 1.55 mm
(0.0r1!l-0.061 inl
Sorvice Llmit:
2.0O mm 10.079 in)
SEAT WIDTH
5. After resurfacing the seat, inspect for even valve
seating; Apply Prussian Blue compound to th€ valve
fEce, and insert valve in original location in the head,
then lift it and snap it closed against the seat sever-
al tames.
o .
VALVE
SEAT
PRUSSIAN BLUE COMPOUI{D
The sctual valve seating surface, as shown by the
blue compound, should be centered on the seat.
a lf it is too high (closer to the valve stem), vou
must make a second cut with the 600 cutter to
move it down, then one more cut with the 45o
cutter to restore seat width.
a lf it is too low (close to the valve edge), you must
make a second cut with the 3Oo cutter to move
it up, then one more cut with the 45o cutter to
restore seat width,
NOTE: The final cut should always be made with
the 45o cutter.
Insert intake and exhaust valves in the head and
measure valve stem installed height.
Intak€ Valv. Stsm lmtallod Height:
Standa.d {Now}: 37.465-37.935
mm
(1.4750- 1.4935 int
So.vic€ Limit: 38.185 mm {1.5033 inl
Exhalst Valve Stom Installad Height:
Standard (Newl: 37.165-37.635 mm
(1 .rt632- 1.rt817 in)
Servico l-imit:
37.885 mm (1.4915 inl
VALVE STEM
INSTALLED HEIGHT
8. lf valve stem installed height is ove. the service limit,
replace valve and recheck. lf still over th€ service
limit, replace cylinder head; the valve seat in the head
is too deeD.
6-97