Mitsubishi S4Q, Руководство пользователя

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69 / 174 Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGLISH
ENGINE MAIN PARTS
10.2.3 Crankshaft
1. Checking oil clearance of connecting rod bearing
1) Install the upper and lower halves of the
bearing and the cap to the connecting rod,
and tighten the cap nuts to the specified
torque. Measure the inside diameter of the
bearing, as shown in the illustration.
2) Measure the diameter of the crankpin of the
crankshaft, as shown in the illustration, and
subtract the diameter of the crankpin from the
inside diameter of the bearing (Step (1)). The
difference is the oil clearance of the
connecting rod bearing.
Unit: mm [in.]
3) If the oil clearance exceeds the repair limit,
replace the bearing and recheck the oil
clearance.
4) If the oil clearance still exceeds the repair
limit, use 0.25 mm [0.0098 in.], 0.50 mm
[0.0197 in.] or 0.75 mm [0.0295 in.] undersize
bearings. When using undersize bearings,
refinish the crankpins to any of the undersizes
listed below.
Unit: mm [in.]
Figure 118 Measuring connecting rod bearing
Measuring
points
Measuring
directions
54 ± 5 N·m
(5.5 ± 0.5 kgf·m)
[40 ± 4 lbf·ft]
Tightening torque
54 ± 5 N·m
(5.5 ± 0.5 kgf·m)
[40 ± 4 lbf·ft]
Figure 119 Measuring crankpin
Measuring
points
Measuring
directions
Item
Nominal
Value
Assembly
Standard
Repair
Limit
Diameter of
crankpin
(standard)
58
[2.28]
57.955 to 57.970
[2.2817 to
2.2823]
__
Oil clearance __
0.03 to 0.09
[0.0012 to
0.0035]
0.20
[0.0079]
Finishing dimension
Undersize
of crankpin
0.25
[0.0098]
57.75 [2.2736 ]
0.50
[0.0197]
57.50 [2.2638 ]
0.75
[0.0295]
57.25 [2.2539 ]
0.030 –
0.045 –
0.0012 –
0.0018 –
0.030 –
0.045 –
0.0012 –
0.0018 –
0.030 –
0.045 –
0.0012 –
0.0018 –