Mitsubishi 3000GT 1991 Service Manual page 87

Oversize I.D.
Description Size mm (in.)
Intake valve 0.3 i.012) 0,s.
0.6 (.024) O.S.
seat insert
Exhaust valve 0.3 l.012) 0,s.
seat insert
0.6 (.024) O.S.
ENGINE
(2) Rebore the valve seat hole in
oversize valve seat diameter.
Valve Seat Insert Oversizes
Seat insEt(,ke;ght H
30 7.5 - 7.7 (.295 - ,303)
60 7.8 - 8.0 (.307 - ,315)
7.9 - 8.1 (.311 - .319)
8.2 - 8.4 t.323 - ,331)
(3) When press-fitting the valve seat, chill the valve seat with
liquid nitrogen so that the cylinder head bore is not
damaged by galling.
(4) Using the valve seat grinder or
to the specified width and angle.
(5) See "VALVE SEAT RECONDITIONING PROCEDURES."
VALVE GUIDE REPLACEMENT PROCEDURE
the cylinder head toward the cylinder block side.
(2) Rebore the valve guide hole to the oversize valve guide
outside diameter to be press-fitted.
Caution
Do not use a valve guide of the same size as the one
removed.
(3) Install the valve guide until a protrusion of 17.5 mm (.689
in.) is obtained. See the illustration.
NOTE
1. Press-fit the valve guide from the cylinder head top
surface.
2. Note the difference in lengths of the valve guides for
the intake and exhaust: intake 45.5 mm (1.791 in.) and
exhaust 50.5 mm (1.988 in.).
3. After the valve guide has been installed in position,
insert a new valve to ensure that it slides smoothly.
Revision
TSB
cylinder head to a selected
Cylinder head I.D.
mm (in.)
36.300-36.325 (1.4291-1.4301)
36.600-36.625 (1.4409-1.4419)
33.300-33.325 (1.3110-1.3120)
33.600-33.625 (1.3228-1.3238)
cutter,
correct the valve seat
12.250-12.268 (.4823-.4830)
12.500-12.518 (.4921-.4928)