Valve Seat Replacement

To replace valve seats, cut valve seat to designated dimension. See Fig 1. Machine cylinder head to proper dimension. See OVERSIZED VALVE SEAT SPECIFICATIONS table.
Heat cylinder head to 480°F (250°C) and press replacement seat into cylinder head. Valve seat height should be within specification. Cut valve seat to proper angle and obtain correct seat width.

Fig 1: Valve Seat Cutting Dimensions & Installed Height Measurement

G90J08798

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

OVERSIZED VALVE SEAT SPECIFICATIONS

Size Mark				Seat SizeIn. (mm)	Cyl. Head Bore In. (mm)	Seat Height In. (mm)
(1.5L)
Precis
Intake
30				.012 (.30)	1.429-1.430 (36.30-36.32)	.299 (7.59)
60				.024 (.61)	1.441-1.442 (36.60-36.63)	.311 (7.89)
(1.5L)
Precis
Exhaust
30				.012 (.30)	1.272-1.273 (32.38-32.33)	.295 (7.49)
60				.024 (.61)	1.283-1.285 (32.59-32.64)	.307 (7.79)
(1.5L)
Mirage
Intake
30				.012 (.30)	1.429-1.430 (36.30-36.32)	.276-.283 (7.01-7.19)
60				.024 (.61)	1.441-1.442 (36.60-36.63)	.287-.295 (7.29-7.49)
(1.5L)
Mirage
Exhaust
30				.012 (.30)	1.272-1.273 (32.38-32.33)	.291-.299 (7.39-7.59)
60				.024 (.61)	1.284-1.285 (32.61-32.64)	.303-.311 (7.70-7.90)
1.6L
Intake
30				.012 (.30)	1.390-1.391 (35.31-35.33)	.311-.319 (7.90-8.10)
60				.024 (.61)	1.402-1.403 (35.61-35.64)	.323-.331 (8.20-8.41)
1.6L
Exhaust
30				.012 (.30)	1.311-1.312 (32.30-33.32)	.311-.319 (7.90-8.10)
60				.024 (.61)	1.323-1.324 (33.60-33.63)	.323-.331 (8.20-8.41)