DETROIT DIESEL 53
Exhaust Valves 1.2.2
Fig. 7. - Removing Valve Seat Insert
1. Place the cylinder head on its side on a bench as
shown in Fig. 7.
2. Place the collet of tool J 7774 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
Fig 8. - Installing Valve Seat Insert
expand the collet cone until the insert is held securely by
depth .300" to .312"
the tool.
NOTE: Valve seat inserts which are .010"
4. Insert the drive bar of the tool through the valve
oversize on the outside diameter are
guide
available, if required.
5. Tap the drive bar once or twice to move the insert
3. Immerse the cylinder head for at least 30 minutes in
about 1/16" away from its seat in the cylinder head.
water heated to 180F. to 200F.
6. Tin the T handle to loosen the collet cone and move
4. Rest the cylinder head, bottom side up, on a bench
the tool into the insert slightly so the narrow flange .t the
and place an insert in the counterbore--valve seat side
bottom of the collet is below the valve seat insert.
up. This must be done quickly while the cylinder head is
still hot and the insert is cold (room temperature). If the
7. Tighten the collet cone and continue to drive the
temperature of the two parts is allowed to become
insert out of the cylinder head.
nearly the same, installation may become difficult and
damage to the parts may result.
Install Exhaust Valve Seat Insert
5. Drive the insert in place with installer or J 7790 as
1. Clean the valve seat insert counterbores in the head
shown in
with trichloroethylene or over suitable solvent. Also
wash the valve seat inserts with the same solvent. Dry
Fig. 8 until it seats solidly in the cylinder head.
the counterbores and the inserts with compressed air.
6. Grind the valve seat insert and check it for
2. Inspect the counterbores for cleanliness,
concentricity in relation to the valve guide as outlined
concentricity, flatness and cracks The counterbores
below.
have a diameter of 1.159" to 1I60" and a
1972 General Motors Corp.
February, 1972
SEC. 1.2.2 Page 5
