TM 9-6115 604-34
NAVFAC P-8-633-34
(12)
Check all threaded holes for stripped threads. Repair stripped threads by installing helical inserts in
accordance with paragraph 2-11.
(13)
Check all capscrews for damaged or stripped threads. Repair minor thread damage by chasing;
replace stripped capscrews.
d.
Rocker Arms, Crossheads, Push Rods, and Followers:
(1)
Inspect, and replace or repair the rocker arms, crossheads, housings, covers, and water transfer tubes
in accordance with paragraph 9-13.
(2)
Inspect, and replace or repair the push rods in accordance with paragraph 9-14.
9-9. CYLINDER HEAD ASSEMBLIES REPAIR.
a.
General. Good valve service life depends upon the careful use of precision equipment during refinishing
operations. Keep all stones properly dressed, and dean the chuck of the valve refacer before each valve is
refinished. Before using the valve refacer for refinishing, test the chuck for accuracy as follows:
(1)
Chuck a new valve in valve refacing machine ST-684, or equivalent, and mount a dial indicator so that
valve face run out can be checked.
(2)
Indicate the around face of the valve and mark the high spot.
(3)
Turn the valve 180 degrees in the chuck, and re-indicate the valve.
(4)
If the high spot is at the same place as marked in step (2), above, and the run out exceeds 0.001 inch
(0.03 mm), the valve is warped. (Through improper handling, it is possible for a new valve to be
warped. ) Select another valve and repeat steps (1) through (3), above.
(5)
If the high spot is at a different place than that in step (2), above, and the run out exceeds 0.001 inch
(0.03 mm), the chuck is out of alignment or the valve is improperly installed in the chuck. Correct the
misalignment, or consult the equipment manual for proper operation of the equipment.
b.
Valves. Reface the intake and exhaust valves as follows:
(1)
Adjust the valve refacer chuck head to an exact 30 degree angle for both intake and exhaust valves.
(2)
Install the valve in the chuck, start the coolant flow, and wet grind the valve until all face imperfections
have been removed.
(3)
Check the rim thickness (A, Figure 9-3) of each reground valve. Discard all valves found to have a rim
thickness under 0.105 inch (2.67 mm).
(4)
Using the V block on the grinding machine, resurface the stem end of the valve.
c.
Valve Seats. Refinish the valve seats as follows (see Figure 9-9):
(1)
Using grinding kit, ST-685 and 3375946 arbor, refinish the valve seats to an exact 30 degree angle. If
necessary, use a coarse stone for rapid metal removal. Final finishing, however, should be done with
a fine stone to leave a bright, dean seat.
(2)
Using eccentric meter ST-685-4, check the valve seat run out. The valve seats shall be finished to a
maximum run out of 0.002 inch (0.05 mm) TIR.
(3)
Check the valve seat width (A and B, Figure 9-9). If the valve seat width is over 0.100 inch (2.54 mm),
narrow the valve seats in accordance with step d, below.
9-14
