Mitsubishi S12A2 User Manual

6-22
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
4.16 Connecting Rod Bearing Thickness - Measure
Measure the thickness of connecting rod at its center.
If the value exceeds the limit, replace both upper and lower
connecting rod bearing shells with new ones as a set.When
the crankshaft is re-ground due to wear of crank pin, use the
undersize bearing.
For the crankshaft grinding procedure, refer to "Crankpin
and Crank Journal - Grind" of "INSPECTION AND
REPAIR OF BASIC ENGINE."
Note: Replacement shells for undersized connecting rod
bearing are available in sizes of 0.25, 0.50, 0.75 and
1.00 mm [0.0098, 0.0197, 0.0295 and 0.0394 in.]
Bearing thickness - Measure
4.17 Connecting Rod Bend and Twist - Inspect
(1) Measure the dimensions of C and L as shown in illus-
tration to check the bend and twist of connecting
rod.Straighten the connecting rod with a press so that
the measurement value meets the standard.
If the value exceeds the limit, replace the connecting
rod with a new one.
Note: Tighten the connecting rod cap to the specified torque
and check the bend and twist.
(2) To inspect the connecting rod with the piston installed,
turn the piston upside down and place it on a surface
plate. Insert a round bar having the same diameter as
the crankpin into the big-end bore, and measure the
height of the bar with dial gauge.
Connecting Rod Bend and Twist - Inspect
Deflection of Connecting Rod - Measure
Measurement
at the center
of bearing
Item Size
Nominal
value
Standard value Limit value
Connecting rod bearing
thickness
Standard
3.000 mm
[0.1181 in.]
2.987 to 3.000 mm
[0.1176 to 0.1181 in.]
2.950 mm
[0.1161 in.]
Under
size
0.25 mm
[0.0098 in.]
3.125 mm
[0.1230 in.]
3.112 to 3.125 mm
[0.1225 to 0.1230 in.]
3.075 mm
[0.1211 in.]
0.50 mm
[0.0197 in.]
3.250 mm
[0.1280 in.]
3.237 to 3.250 mm
[0.1274 to 0.1279 in.]
3.200 mm
[0.1260 in.]
0.75 mm
[0.0295 in.]
3.375 mm
[0.1329 in.]
3.362 to 3.375 mm
[0.1324 to 0.1329 in.]
3.325 mm
[0.1309 in.]
1.00 mm
[0.0394 in.]
3.500 mm
[0.1378 in.]
3.487 to 3.500 mm
[0.1373 to 0.1378 in.]
3.450 mm
[0.1358 in.]
Item Standard value
Connecting rod bend and twist
(C/L, C/D)
0.05/100 mm
[0.0020/3.94 in.] or less
343 ± 17.7 N·m
{35 ± 1.8 kgf·m} [253 ± 13.0 lbf·ft]
2-Step tightening [wet]
Piston pin
Connecting rod twist
Connecting rod bend
Tor qu e
Unit: mm [in.]
L
L
C
C
3.94
[ ]
0.05
100
C
L
[ ]
3.94
100
0.05
C
L
0.0020
0.0020
C
D
D
C
0.05 [0.0020]
Unit: mm [in.]
Surface plate
100 [3.94]

Mitsubishi S12A2 Specifications

General

Brand	Mitsubishi
Model	S12A2
Category	Engine
Language	English