Mitsubishi S12A2, Service Manual

Page: 120 / 354

6-16
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
4.5 Piston Pin Bore Inside Diameter - Measure
Measure the piston pin bore inside diameter.If the value
exceeds the limit, replace the piston with a new one.
Piston Pin Bore Inside Diameter - Measure
4.6 Piston Ring - Inspect Visually
Check the sliding surface and top and bottom surfaces for
seizing, abnormal wear, foreign material inclusion and plat-
ing flaking.If any defects are found, replace the piston rings
with new ones.
4.7 Piston Ring End Gap - Measure
Place the piston ring in the gauge or a new cylinder liner,
and measure the end gap.If the value exceeds the limit,
replace piston rings with a new set of rings.
Note: Using a piston, push the piston ring squarely into
gauge or cylinder liner.
Piston Ring End Gap - Measure
4.8 Piston Pin Outside Diameter - Measure
Measure the piston pin outside diameter.
If the value exceeds the limit, replace the piston pin with a
new one.
Piston Pin Outside Diameter - Measure
Item
Nominal
value
Standard value Limit value
Piston pin bore
inside diameter ø58 mm
[2.28 in.]
58.002 to 58.012 mm
[2.2835 to 2.2839 in.]
58.040 mm
[2.2850 in.]
Measurement
direction
Measurement
point
Item Standard value Limit value
Piston ring
end gap
No.1
compression 0.6 to 0.8 mm
[0.024 to 0.032 in.]
2.0 mm
[0.078 in.]
No.2
compression 0.5 to 0.7 mm
[0.020 to 0.028 in.]
Oil
0.5 to 0.7 mm
[0.020 to 0.028 in.]
Thickness gauge
End gap
Gauge diameter: Gauge diameter:
150 ± 150 ± 0 mm [5.91 0 mm [5.91 ± ± 0 in.] 0 in.]
Gauge diameter:
150 ± 0 mm [5.91 ± 0 in.]
Item
Nominal
value
Standard value Limit value
Piston pin out-
side diameter ø58 mm
[2.28 in.]
57.987 to 58.000 mm
[2.2830 to 2.2834 in.]
57.970 mm
[2.2823 in.]
Measurement
direction
Measurement
point