Honda Prelude 1993 Service Manual page 120

Valve Seats
Reconditioning
Renew the valve seats in the cylinder head using a
valve seat cutter.
NOTE: lf guides are worn (page 6-52), replace them
(page 6-531 betore cutting the valve seats.
Carefully cut a 45o se8t. removing only enough
material to ensure a smooth and concentric seat.
Bevel the upper edge of the seat whh the 3Oo cutter
and the lowsr edg€ of the seat with the 600 cutter,
Check width of sest and adjust accordingly.
Make one more very ligt|t pass whh tha 45o cutte, to
remove any possible burrs caussd by the other cufters.
VCv. Sct Wld$ (ht!k
lnd.xhaltl:
Standlrd: 1.25- 1.55 mm
(O.O49-O.061 int
Sendce llmh: 2.0O mm (0.079 in)
o
K@"8
After resurfacing the seat, inspect Jor even valv€
seating: Apply Prussian Blue compound to the valve
face, and insen valv€ in original location in the he8d,
then lift it and snap it closed against the seat sever-
al times.
ACTUAL
SEAN G
SURFACE
VALVE
SEAT
PRUSSIAN BLUE COMPOUI{D
The actual vslve seating sudace, as shown by the
blue compound, should bo centered on the seat.
a lf it is too high (closer to the valv6 stem), you
must make a second cut with the 600 cuttef to
move it down, then onB more cut with the 45o
cutter to rgstore saat width.
a ]f it is too low (close to th6 valve edge), you must
make a second cut with the 30o cutter to move
it up, then one more cut with the 45o cutter to
restore seat width.
NOTE: The tinal cut shoutd always be made wirh
the 45o cutter.
Insen intake and exhaust valves in the head and
measuro valve stem installed height.
Intake Valve St.m Inliall.d Hright:
Standard (l{cwl: 39.365-39.835
mm
(1.5498- 1.5683 inl
Scrvlce Limlt:
4O.Oa5 (1.5781 tnl
Exhau* Valve Stom lnstallcd Hdght:
Standard (Now): 39.165-39.635 mm
1 1 . 5 4 1 9 - 1 . 5 6 0 4 i n l
S.rvlce Limit: 39.885 mm ('1.5703 inl
)
VALVE STEM
INSTALLED HEIGHT
8. It valve stem installed height is over the service limit,
replace valve and recheck. lf still ovef the service
limit, replace cylinder head; the valve seat in the head
is too deeo.
6 -5 1