DETROIT DIESEL 53
Exhaust Valves 1.2.2
Fig. 7 - Removing Valve Seat Insert
J 7774 (four valve head) inside the valve insert so that the
bottom of the collet is flush with the bottom of the 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.
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 " away from its seat in the cylinder head.
Fig. 8 - Installing Valve Seat Insert
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.
Tighten the collet cone and continue to drive the insert out of the cylinder head.
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 in a four valve head
have a diameter of 1.159 " to 1.160 " and a depth of .294 " to .306 " on former engines and a depth of .300 " to .312 " on
NOTE: Valve seat inserts which are .010" oversize on the outside diameter are
available, if required.
Immerse the cylinder head for at least 30 minutes in water heated to 180 °F. to 200 °F.
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
5. Drive the insert in place with installer J 7790 (four valve head) as shown in Fig. 8 until it seats solidly in the cylinder
Grind the valve seat insert and check it for concentricity in relation to the valve guide as outlined below.
Recondition Exhaust Valve and Valve Seat Insert
An exhaust valve which is to be reused may be refaced, if necessary (Fig. 9). To provide sufficient valve strength and
spring tension, the edge of the