Mitsubishi Heavy Industries S3L, Service Manual

Page: 63 / 200

INSPECTION AND REPAIR OF BASIC ENGINE
6-3
1.4 Measuring push rod runout
Measure the runout of push rod. If the standard value is
exceeded, replace the push rod.
Measuring push rod runout
1.5 Measuring valve stem outside diameter and
valve guide inside diameter
Measure the diameter at the top and bottom ends at right
angles to the outer and inner surfaces, since valve stems and
valve guides are more likely to wear at both ends. If the
outside diameter is less than the limit, or the clearance
exceeds the limit, replace either the valve or the valve guide
with a new one.
Measuring valve stem outside diameter
Measuring valve guide inside diameter
1.6 Replacing valve guide
(1)
Remove the valve guide with a punching tool pressing
from the cylinder head bottom surface.
(2)
When press-fitting the new valve guide, press-fit the
valve guide with a press from the cylinder head top
surface.
(3)
After press-fitting the valve guide, insert the valve and
check the movement.
(4)
When replacing the valve with new one, check the
contact between the valve and the valve seat.
Replacing valve guide
Item Standard Remark
Push rod
runout 0.3 mm
[0.012 in.] or less
Total indicated reading
(TIR)
1/2 1/2
Push rod
Item Nominal Standard Limit
Valve
stem outside
diameter
Inlet
ø 6.6 mm
[0.260 in.]
6.565 to 6.580 mm
[0.2585 to 0.2591 in.]
6.500 mm
[0.2559 in.]
Exhaust
ø 6.6 mm
[0.260 in.]
6.530 to 6.550 mm
[0.2571 to 0.2579 in.]
6.500 mm
[0.2559 in.]
Clearance
between
valve stem
and valve
guide
Inlet -
0.020 to 0.050 mm
[0.0008 to 0.0020 in.]
0.100 mm
[0.0039 in]
Exhaust -
0.050 to 0.085 mm
[0.0020 to 0.0033 in.]
0.150 mm
[0.0059 in.]
Valve guide mounting
dimension 10 mm
[0.39 in.]
9.5 to 10.5 mm
[0.374 to 0.413 in.]
-
Measuring
directions
Measuring
points
Inside
micrometer
Measuring
directions
Measuring
points
Valve guide
Cylinderhead
10 ± 0.5 mm [.0394 ± 0.020 in.]
15 mm [0.591 in.]