Mitsubishi S6R Series User Manual

6-27
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
5.5 Crankpin and Journal Outside Diameters - Measure
(1) Measure the outside diameter of crankpins and crank
journals.
If the value exceeds the limit, use an undersize bearing,
and grind the crankshaft for use with undersized bear-
ing.
If the specified limit is exceeded even if the -1.00 mm
[-0.0394 in.] undersize bearing is used, replace the
crankshaft with a new one.
(2) know the roundness and cylindricity based on measured
values.
5.5.1 Crankpin and Crank Journal - Grind
When using the undersize bearing, grind to the standard
value corresponding to undersize bearing to be used.
Do not change the fillet radius and bearing journal width
when grinding. Quench the crankshaft if its surface hard-
ness is significantly decreased, and after quenching do the
magnetic particle inspection.
After grinding, measure the width of crankpin journals and
rearmost crank main journal.
Crankpin Outside Diameter - Measure
Crank Journal Outside Diameter - Measure
Measurement
direction
Measurement
point
Measurement
direction
Measurement
point
Item
Nominal
value
Size Standard value Limit value
Crankpin outside diameter
ø125 mm
[4.92 in.]
Standard 124.930 to 124.950 mm [4.9185 to 4.9193 in.] 124.890 mm [4.9169 in.]
Under
Size
0.25 mm [0.0098 in.] 124.680 to 124.700 mm [4.9087 to 4.9094 in.] 124.640 mm [4.9071 in.]
0.50 mm [0.0197 in.] 124.430 to 124.450 mm [4.8988 to 4.8996 in.] 124.390 mm [4.8972 in.]
0.75 mm [0.0295 in.] 124.180 to 124.200 mm [4.8890 to 4.8898 in.] 124.140 mm [4.8874 in.]
1.00 mm [0.0394 in.] 123.930 to 123.950 mm [4.8791 to 4.8799 in.] 123.890 mm [4.8775 in.]
Crankshaft main journal out-
side diameter
ø140 mm
[5.51 in.]
Standard 139.930 to 139.950 mm [5.5090 to 5.5098 in.] 139.890 mm [5.5075 in.]
Under
Size
0.25 mm [0.0098 in.] 139.680 to 139.700 mm [5.4492 to 5.5000 in.] 139.640 mm [5.4976 in.]
0.50 mm [0.0197 in.] 139.430 to 139.450 mm [5.4894 to 5,4901 in.] 139.390 mm [5.4878 in.]
0.75 mm [0.0295 in.] 139.180 to 139.200 mm [5.4795 to 5.4803 in.] 139.140 mm [5.4779 in.]
1.00 mm [0.0394 in.] 138.930 to 138.950 mm [5.4697 to 5.4705 in.] 138.890 mm [5.4681 in.]
Pin
and
journal
Parallelism - -
Pin defection at pin length: 0.01 [0.0004] or
less
0.01 mm [0.0004] or less
0.03 mm [0.0012 in.]
Roundness - -
Diameter difference: 0.01 mm [0.0004 in.] or
less
0.03 mm [0.0012 in.]
Cylindricity - -
Diameter difference: 0.01 mm [0.0004 in.] or
less
0.03 mm [0.0012 in.]
Fillet
radius
Pin
R7
[0.28 in.]
- 6.8 to 7.0 mm [0.268 to 0.276 in.] -
Main
journal
R7
[0.28 in.]
- 6.8 to 7.0 mm [0.268 to 0.276 in.] -
Hardness - - Hv > 620 -
Surface roughness - - Ra 0.2 μm [0.008 µin.] -
Angular deviation between
pins
- - ±20' -

Mitsubishi S6R Series Specifications

General

Brand	Mitsubishi
Model	S6R Series
Category	Engine
Language	English