Mitsubishi Motors 4G1 - Manual (Page 76)

4G1 ENGINE (E - W) - Cylinder Head and Valves
11A-9-7
PWEE9520
E
Nov. 1995 Mitsubishi Motors Corporation
VALVE SEAT CORRECTION SERVICE POINTS
(1) Before correcting the valve seat, check the clearance
between the valve guide and valve. If necessary, replace
the valve guide.
(2) Using the appropriate special tool or seat grinder, correct
the valve seat to achieve the specified seat width and
angle.
(3) After correcting the valve seat, lap the valve and valve
seat using lapping compound. Then, check the valve stem
projection (refer to 5. VALVE SEATS in INSPECTION).
VALVE SEAT REPLACEMENT SERVICE
POINTS
(1) Cut the valve seat to be replaced from the inside to reduce
the wall thickness. Then, remove the valve seat.
(2) Rebore the valve seat hole in the cylinder head to match
the selected oversize valve seat diameter.
Valve seat diameters
Standard mm
SOHC In- Primary 0.30 O.S. 27.300 - 27.325
12-VALVE take
0.60 O.S. 27.000 - 27.625
Secondary 0.30 O.S. 32.300 - 32.325
0.60 O.S. 32.600 - 32.625
Exhaust 0.30 O.S. 35.300 - 35.325
0.60 O.S. 35.600 - 35.625
SOHC Intake 0.30 O.S. 28.300 - 28.321
16-VALVE
0.60 O.S. 28.600 - 28.621
<4G13>
Exhaust 0.30 O.S. 26.300 - 26.321
0.60 O.S. 26.600 - 26.621
SOHC Intake 0.30 O.S. 30.300 - 30.321
16-VALVE
0.60 O.S. 30.600 - 30.621
<4G18>
Exhaust 0.30 O.S. 28.300 - 28.321
0.60 O.S. 28.600 - 28.621
DOHC Intake 0.30 O.S. 31.300 - 31.325
0.60 O.S. 31.600 - 31.625
Exhaust 0.30 O.S. 27.800 - 27.825
0.60 O.S. 28.100 - 28.125
(3) Prevent galling of the cylinder head bore by cooling the
valve seat with liquid nitrogen before press-fitting it.
(4) Correct the valve seat to achieve the specified width and
angle (refer to VALVE SEAT CORRECTION SERVICE
POINTS).
PWEE9520-A
E
Dec. 1998 Mitsubishi Motors Corporation Revised
0.9 - 1.3 mm
0.9 - 1.3 mm
65 _
65 _
15 _
15 _ 44 _
44 _
Cut away
1EN0274
0.5 - 1.0 mm
0.5 - 1.0 mm
Valve seat
height
Oversize hole I. D.
1EN0275