Valve Seat Reconditioning - Honda Civic Service Manual

Valve Seat Reconditioning
1. Inspect valve stem-to-guide clearance (see page 6-
32). lf the valve guides are worn, replace them (see
page 6-33) before cutting the valve seats.
2 . R e n e w t h e v a l v e s e a t s i n t h e c y l i n d e r h e a d u s i n g a
valve seat cutter.
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 and lower edges at the angles
shown in the illustration.
Check the width of the seat and adjust accordingly.
INTAKE:35"
EXHAUST:30'
3 ,
4 .
- 45'
, { 6 7 . 5 '
5. Make one more very light pass with the 45" cutter
to remove any possible burrs caused by the other
cutters.
Valve Seat Width:
Standard (New): 1.25 1.55 mm {0.049 0.061 in.)
Service Limit:
2.00 mm (0.079 in.)
6. After resurfacing the seat, inspect for even valve
s e a t i n g : A p p l y P r u s s i a n B l u e c o m p o u n d ( A ) t o t h e
v a l v e f a c e . I n s e r t t h e v a l v e i n i t s o r i g i n a l l o c a t i o n i n
the head, then lift it and snap it closed against the
seat several trmes.
1 . The actual valve seating surface (B), 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 67.5' cutter to
move it down, then one more cut with the 45"
cutter to restore seat width.
. lf it is too low (close to the valve edge), you must
make a second cut with the 35'cutter (intake
sidel or the 30" cutter (exhaust side) to move it up,
then make one more cut with the 45" cutter to
restore seat width.
N O T E : T h e f i n a l c u t s h o u l d a l w a y s b e m a d e w i t h
the 45'cutter.
( c o n t ' d )
6-35