Mitsubishi 4G9 User Manual

4G9 ENGINE (E-W) -
Cylinder Head and Valves
11A-9-11
PWEE9502-C
E
July 1997Mitsubishi Motors Corporation
Revised
VALVE SEAT RECONDITIONING PROCEDURE
(1) Before correcting the valve seat, check the clearance
between the valve guide and valve. If necessary, replace
the valve and/or 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 VALVE SEAT in INSPECTION).
VALVE SEAT REPLACEMENT PROCEDURE
(1) Cut the valve seat to be replaced from the inside to thin
the wall thickness. Then, remove the valve seat.
(2) Rebore the valve seat hole in the cylinder head to a
selected oversize valve seat diameter.
Intake valve seat hole diameter
0.3 O.S. <SOHC>: 31.80 - 31.83 mm
<DOHC>: 34.30 - 34.33 mm
0.6 O.S. <SOHC>: 32.10 - 32.13 mm
<DOHC>: 34.60 - 34.63 mm
Exhaust valve seat hole diameter
0.3 O.S. <SOHC>: 29.30 - 29.32 mm
<DOHC>: 30.80 - 30.83 mm
0.6 O.S. <SOHC>: 29.60 - 29.62 mm
<DOHC>: 31.10 - 31.13 mm
(3) Before fitting the valve seat, either heat the cylinder head
up to approximately 250
_
C or cool the valve seat in liquid
nitrogen, to prevent the cylinder head bore from galling.
(4) Correct the valve seat to the specified width and angle.
VALVE GUIDE REPLACEMENT
(1) Force the valve guide out toward the cylinder block using
a press.
(2) Machine the valve guide hole in the cylinder head to
the size of the oversize valve guide to be installed.
Caution
Do not use the valve guide of the same size as the
removed one.
Valve guide hole diameters in cylinder head
0.05 O.S.: 11.05 - 11.07 mm
0.25 O.S.: 11.25 - 11.27 mm
0.50 O.S.: 11.50 - 11.52 mm
0.9 - 1.3 mm
0.9 - 1.3 mm
65
_
65
_
44
_
44
_
15
_
15
_
0.5 - 1.0 mm
Cut away
0.5 - 1.0 mm
Valve seat
height
Oversize valve seat
hole diameter

Mitsubishi 4G9 Specifications

General

Brand	Mitsubishi
Model	4G9
Category	Engine
Language	English

Summary

ENGINE 4G9 SERIES

SPECIFICATIONS

Details on engine specifications, including service, rework, torque, and material requirements.

SPECIAL TOOLS

List and description of specialized tools required for engine service procedures.

ALTERNATOR AND IGNITION SYSTEM

Procedures for removal and installation of alternator and ignition system components.

TIMING BELT

Removal, installation, inspection, and adjustment procedures for the timing belt system.

FUEL AND EMISSION CONTROL SYSTEM

Procedures for removal and installation of fuel and emission control system components.

INTAKE AND EXHAUST MANIFOLD

Procedures for removal and installation of intake and exhaust manifolds for various models.

WATER PUMP AND WATER HOSE

Procedures for removal and installation of the water pump and associated hoses.

ROCKER ARMS AND CAMSHAFTS

Procedures for removal, installation, inspection, and adjustment of rocker arms and camshafts.

CYLINDER HEAD AND VALVES

Procedures for cylinder head and valve removal, installation, inspection, and handling.

FRONT CASE AND OIL PUMP

Procedures for removal, installation, and inspection of the front case and oil pump.

PISTON AND CONNECTING ROD

Procedures for removal, installation, and inspection of pistons and connecting rods.

CRANKSHAFT, CYLINDER BLOCK, FLYWHEEL AND DRIVE PLATE

Procedures for removal, installation, and inspection of crankshaft, cylinder block, and related components.