Mitsubishi S4Q2 User Manual

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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGLISH
ENGINE MAIN PARTS
7.2.4 Valves, valve guides and valve seats
1. Measuring valve stem
Measure the diameter of the valve stem, as shown
in the illustration. If the service limit is exceeded,
replace the valve.
Unit: mm [in.]
2. Checking clearance between valve stem and guide
The valve guide wears more rapidly at its both
ends than at any other parts. Measure the inside
diameter of the valve guide at its ends, as shown in
the illustration, to check the clearance. If the
clearance exceeds the service limit, replace the
guide or valve whichever is badly worn.
Unit: mm [in.]
Figure 21 Measuring valve stem
Measuring
directions
Measuring points
Item
Nominal
Value
Assembly
Standard
Service
Limit
Valve
stem
diameter
Inlet
valves
8
[0.315]
7.940 to
7.955
[0.3126 to
0.3132]
7.900
[0.3110]
Exhaust
valves
8
[0.315]
7.920 to
7.940
[0.3118 to
0.3126]
7.850
[0.3091]
Figure 22 Measuring valve guide
Inside micrometer caliper
Item
Nominal
Value
Assembly
Standard
Repair
Limit
Clearance
between
valve
stem and
guide
Inlet
valves
__
0.065 to
0.095
[0.0026 to
0.0037]
0.200
[0.0079]
Exhaust
valves
__
0.080 to
0.115
[0.0032 to
0.0045]
Height to top of valve
guide
15.5
[0.61]
15.1 to 15.6
[0.5945 to
0.6142]
__
NOTE
Before measuring the valve guides, clean the guides,
removing lacquer or other deposits by running wire
brush through them.

Mitsubishi S4Q2 Specifications

General

Brand	Mitsubishi
Model	S4Q2
Category	Engine
Language	English