ARMY TM 9-2815-252-24
AIR FORCE TO 38G1-92-2
TABLE 3-4. Cylinder Head Component Wear Limits
Hydraulic tappet diameter
Hydraulic tappet bore
Valve spring free length
(See Note Below)
Valve guide bore -
Valve stem diameter
Replace the spring if the length is 1.67 in. (42.5 mm) or less.
b. Check that intake valve seat is sunk 0.037 to 0.05 in. (0.95 to 1.26 mm) and exhaust valve seat is sunk 0.052
to 0.065 in. (1.33 to 1.64 mm) below combustion surface. If not, regrind valve seats, refer to paragraph 3-
c. Check cylinder head clearance as follows:
This procedure is used to determine what size head gasket is required. Start with medium size gasket.
(1) Place head gasket onto crankcase. Align holes in gasket with those in crankcase. Rotate engine so
pistons are below cylinder head deck.
(2) Using a very small amount of general purpose grease 630AA), place four pieces of solder
(SN60WRAP2) size 0.062 in. (1.58 mm) thick on pistons as shown in FIGURE 3-30. Space solder on
outer edge and as near as possible in line with piston pin. Care must be taken to ensure that solder will
be clear of valve recesses.
(3) Install cylinder head and torque bolts, refer to paragraph 3-27.6.
(4) Manually rotate engine through two complete revolutions.