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6-28 ENGINE TOP END
Valves
•
Measure the outside diameter of the seating surface with
a vernier caliper.
If the outside diameter of the seating surface is too small,
repeat the 45° grind until the diameter is within the spec-
ified range.
Widened Width [A] of engagement by machining with
45° cutter
Ground Volume [B] by 32° cutter
32° [C]
Correct Width [D]
Ground Volume [E] by 60° or 55° cutter
60° or 55° [F]
•
Measure the outside diameter of the seating surface with
a vernier caliper.
If the outside diameter of the seating surface is too small,
repeat the 45° grind [A] until the diameter is within the
specified range.
Original Seating Surface [B]
NOTE
○
Remove all pittings of flaws from 45° ground surface.
○
After grinding with 45° cutter, apply thin coat of machin-
ist’s dye to seating surface. This m akes seating surface
distinct and 32° and 60° grinding operation easier.
○
When the valve guide is replaced, be sure to grind with
45° cutter for centering and good contact.
If the outside diameter [A] of the seating surface is too
large, make the 32° grind described below.
If the outside diameter of the seating surface is within the
specified range, measure the seat width as described be-
low.
•
Grind the seat at a 32° angle [B] until the seat O.D. is
within the specified range.
○
To make the 32° grind, fit a 32° cutter into the holder, and
slide it into the valve guide.
○
Turn the holder one turn at a time while pressing down
very lightly. Check the seat after each turn.
CAUTION
The 32° cutter removes material very quickly.
Check the seat outside diameter frequently to pre-
vent overgrinding.
○
After making the 32° grind, return to the seat O.D. mea-
surement step above.
•
To measure the seat width, use a vernier caliper to mea-
sure the width of the 45° angle portion of the seat at sev-
eral places around the seat.
If the seat width is too narrow, repeat the 45° grind until
the seat is slightly too wide, and then return to the seat
O.D. measurement step above.