Piston And Connecting Rod - Inspect And Repair; Piston - Inspect Visually; Piston Weight; Piston Outside Diameter - Measure - Mitsubishi S6R Series Service Manual

4. Piston and Connecting Rod - Inspect and Repair

4.1 Piston - Inspect Visually

Check the combustion surface, piston pin bore, ring groove,
sliding surface and bottom surface of piston. If any defect
are found, replace the piston with a new one.

4.2 Piston Weight

Check the piston weight on the top face of piston.
When replacing pistons, be sure that the weight difference
per engine is within permissible range.
Item Part No. ID stamp
37517-30101
37517-10401
37517-00900
37517-25100
Piston
37517-05500
weight
37517-05300
difference
37517-07800
37517-07900
37517-00800

4.3 Piston Outside Diameter - Measure

Measure the piston outside diameter of piston skirt at right
angle to piston pin. If the value exceeds the limit, replace
the piston with a new one.
Nominal
Item Part No.
37517-30101
37517-10401
37517-00900 ø170 mm
37517-25100 [6.69 in.]
37517-05500
37517-05300
Piston
outside
37517-07800 ø170 mm
diameter
37517-07900 [6.69 in.]
ø170 mm
37517-00800
[6.69 in.]
Compression Standard
ratio value
30101 14
10401 15
00900 14.5
25100 14 within 10 g
05500 14 [0.35 oz]
05300 14
07800 14
07900 15
within 15 g
00800 14
[0.53 oz]
Standard
Limit value
value value
169.760 to
169.800 mm 169.660 mm
[6.6835 to [6.6795 in.]
6.6850 in.]
169.739 to
169.779 mm 169.639 mm
[6.6826 to [6.6787 in.]
6.6842 in.]
169.760 to
169.780 mm 169.660 mm
[6.6835 to [6.6795 in.]
6.6842 in.]
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
ID mark
(Last 5 digits of PN)
Direction mark
Piston Outside Diameter - Measure
Piston - Inspect Visually
Piston weight mark
Piston Weight Stamp
Measurement
point
6-17