Mitsubishi S6R Series User Manual

6-18
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
4.4 Piston Ring Groove - Inspect
(1) Remove all deposits such as carbon from each ring
groove.
(2) Visually check each ring groove for wear or damage. If
faulty, replace the piston with a new one. Inspect the
ring insert of No. 1 compression ring groove by dye
penetration test for cracks and separation.
Piston Ring Groove - Inspect
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
Remove carbon deposits from piston and inspect the
entire circumference of piston.
Ring insert
No. 1 compression ring
groove
No. 2 compression ring
groove
Oil ring groove
Item
Nominal
value
Standard value Limit value
Piston pin bore
inside diameter
ø70 mm
[2.76 in.]
70.002 to 70.015 mm
[2.7560 to 2.7565 in.]
70.040 mm
[2.7575 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.]
1.0 mm
[0.040 in.]
No.2
compression
0.6 to 0.8 mm
[0.024 to 0.032 in.]
Oil
0.3 to 0.45 mm
[0.012 to 0.0177 in.]
0.6 mm
[0.024 in.]
Thickness gauge
Gauge inside diameter: 170 ± 0 mm [6.69 ± 0 in.]
End gap

Mitsubishi S6R Series Specifications

General

Brand	Mitsubishi
Model	S6R Series
Category	Engine
Language	English