Mitsubishi 3000GT 1991, Service Manual

Page: 87 / 1146

ENGINE
Cylinder Head and Valve
Oversize I.D.
Valve
(2) Rebore the valve seat hole in
oversize valve seat diameter.
Seat Insert Oversizes
cylinder head to a selected
Description Size mm (in.) Size mark
Seat H Cylinder head I.D.
mm (in.)
Intake valve 0.3 30 7.5 7.7 ,303) 36.300-36.325
seat insert
0.6 O.S. 60 7.8 8.0 36.600-36.625
Exhaust valve
seat insert 0.3
7.9 8.1 33.300-33.325
0.6 O.S.
8.2 8.4 33.600-33.625 (1.3228-1.3238)
(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
cutter,
correct the valve seat
to the specified width and angle.
(5) See “VALVE SEAT RECONDITIONING PROCEDURES.”
VALVE GUIDE REPLACEMENT PROCEDURE
Using suitable rod and a press, press the valve guide out of
the cylinder head toward the cylinder block side.
(2) Rebore the valve guide hole to the oversize valve guide
outside diameter be press-fitted.
Caution
Do not use a valve guide of the same size as the one
removed.
12.250-12.268
12.500-12.518
(3) Install the valve guide until a protrusion of 17.5 mm
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.
TSB
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