TM 9-2320-260-34-1
3-80. VALVE SEAT GRINDING (Contd)
c. Valve Seat Grinding
CAUTION
Too much pressure on grinder driver may cause excessive wear
on grinder wheel stone, distorting the cut on the valve seat and
removing too much material.
NOTE
After each seat has been ground, redress grinder wheel stone to a
30 angle. Grinder wheel stone wears with use.
Turn grinder motor switch to "ON" position.
1.
CAUTION
Do not apply side pressure to electric grinder motor. This action
will cause the valve seat to grind off-center and cause damage to
valve seat.
NOTE
Seat area "A" is 0.063-0.125 in. (1.600-3.175 mm), maximum.
Seat area "B" is 0.125 in. (3.175 mm), maximum. If seat area "B"
is greater than 0.125 in. (3.175 mm), stock can be removed using
a specially dressed valve seat grinder wheel stone.
2. Apply light, vertical pressure on grinder driver and grind valve seat (1).
3. Turn electric grinder motor switch to "OFF position and remove grinder driver and grinder wheel
stone from valve guide arbor and cylinder head (2). Leave valve guide arbor in position for gaging
valve seats (1).
WARNING
Drycleaning solvent is flammable and will not be used near open
flame. Use only in well-ventilated places. Failure to do so may
result in injury to personnel.
Compressed air source will not exceed 30 psi (207 kPa). When
cleaning with compressed air, eyeshields must be worn. Failure
to wear eyeshields may result in injury to personnel.
Using compressed air, blow cylinder head (2) clean of dirt, debris, metal shavings, and grindings.
1.
2. Using a wire brush and drycleaning solvent, clean all valve seats (1) and ports in cylinder head (2).
e. Gaging Valve Seats
Position dial indicator on valve guide arbor with indicator finger on valve seat (1).
1.
NOTE
Total valve seat runout must not exceed 0.002 in. (0.0508 mm).
2. Turn dial indicator clockwise two or three turns and observe needle for runout. If valve seat (1)
runout exceeds 0.002 in. (0.0508 mm), regrind valve seat (1) and clean cylinder head (2)
(subtasks c. and d.).
3. Remove dial indicator from valve guide arbor.
4. Remove valve guide arbor from cylinder head (2).
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