Mitsubishi S12A2 User Manual

6-25
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
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.If a remarkable decrease in hardness is found,
quench the crankshaft again and inspect it with the magnetic
particle inspection.
After grinding, measure the width of crankpin journals and
rearmost crank main journal.
Crank Journal Outside Diameter - Measure
Measurement
direction
Measurement
point
Item
Nominal
value
Size
Standard value Limit value
Crankpin outside diameter
ø104 mm
[4.09 in.]
Standard
103.900 to 103.920 mm
[4.0904 to 4.0912 in.]
103.860 mm
[0.019 in.]
Under
size
0.25 mm
[0.0098 in.]
103.650 to 103.670 mm
[4.0806 to 4.0814 in.]
103.610 mm
[4.0790 in.]
0.50 mm
[0.0197 in.]
103.400 to 103.420 mm
[4.0708 to 4.0716 in.]
103.360 mm
[4.0692 in.]
0.75 mm
[0.0295 in.]
103.150 to 103.170 mm
[4.0609 to 4.0617 in.]
103.110 mm
[4.0593 in.]
1.00 mm
[0.0394 in.]
102.900 to 102.920 mm
[4.0511 to 4.0519 in.]
102.860 mm
[4.0495 in.]
Crankshaft main journal outside diame-
ter
ø130 mm
[5.1180 in.]
Standard
129.880 to 129.900 mm
[5.1133 to 5.1140 in.]
129.840 mm
[5.1117 in.]
Under
size
0.25 mm
[0.0098 in.]
129.630 to 129.650 mm
[5.1034 to 5.1042 in.]
129.590 mm
[5.1018 in.]
0.50 mm
[0.0197 in.]
129.380 to 129.400 mm
[5.0936 to 5.0944 in.]
129.340 mm
[5.0920 in.]
0.75 mm
[0.0295 in.]
129.130 to 129.150 mm
[5.0837 to 5.0845 in.]
129.090 mm
[5.0822 in.]
1.00 mm
[0.0394 in.]
128.880 to 128.900 mm
[5.0739 to 5.0747 in.]
128.840 mm
[5.0723 in.]
Pin and
journal
Parallelism - -
Deviation of 0.01 [0.0004] or less over
entire pin length
0.03 mm
[0.0012 in.]
Roundness - - Diameter difference 0.01 [0.0004] or less
0.03 mm
[0.0012 in.]
Cylindricity - - Diameter difference 0.01 [0.0004] or less
0.03 mm
[0.0012 in.]
Fillet radius
Pin
R7
[0.28]
-
6.8 to 7.0 mm
[0.268 to 0.276 in.]
-
Journal
R7
[0.28]
-
6.8 to 7.0 mm
[0.268 to 0.276 in.]
-
Hardness - - Hv > 620 -
Finishing surface rough-
ness
-- Ra0.2μm-
Angular deviation between pins - - ±0.3° -

Mitsubishi S12A2 Specifications

General

Brand	Mitsubishi
Model	S12A2
Category	Engine
Language	English