TM 5-3895-346-14
ENGINE OVERHAUL
EXHAUST VALVES
Figure 9. Removing Valve Seat Insert
3. Hold the collet handle and turn the T-handle to expand the collet cone until the insert is held securely by
the tool.
4. Insert the drive bar of the tool through the valve guide.
5. Tap the drive bar once or twice to move the insert about 1/16 inch away from its seat in the cylinder head.
6. Turn the T-handle to loosen the collet cone and move the tool into the insert slightly so the narrow flange
at the bottom of the collet is below the valve seat insert.
7. Tighten the collet cone and continue to drive the insert out of the cylinder head.
NOTE
In addition to the above procedure, remover J 23479-15 and appropriate collet can
be used to remove the exhaust valve insert from the cylinder head.
Install Exhaust Valve Seat Insert
1. Clean the valve seat insert counterbores in the head with trichloroethylene or other suitable solvent. Also
wash the valve seat inserts with the same solvent. Dry the counterbores and the inserts with compressed air.
2. Inspect the counterbores for cleanliness, concentricity, flatness, and cracks. The counterbores for the
valve seat inserts in a two-valve head have a diameter of 1.439 to 1.440 inches and a depth of 0.294 to 0.306
inch. The counterbores for the valve seat inserts in a four-valve head have a diameter of 1.159 to 1.160 inches
and a depth of 0.294 to 0.306 inch on former engines and a depth of 0.300 to 0.312 inch on current engines.
NOTE
Valve seat inserts which are 0.010 inch oversize on the outside diameter are available, if required.
3. Immerse the cylinder head for at least 30 minutes in water heated to 180-200 (82-93 ).
F
C
4. Rest the cylinder head, bottom side up, on a bench and place an insert in the counterbore--valve seat side
up. This must be done quickly while the cylinder head is still hot and the insert is cold (room temperature). If
the temperature of the two parts is allowed to become nearly the same, installation may become difficult and
damage to the parts may result.
5. Drive the insert in place with installer J 6976 (two-valve head) or J 7790 (four-valve head) as shown in
Fig. 10 until it seats solidly in the cylinder head.
6. Grind the valve seat insert and check it for concentricity in relation to the valve guide as outlined below.
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