Mitsubishi S4Q, Руководство пользователя

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70 / 174 Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
2. Checking oil clearance of main bearing
1) Install the upper and lower halves of the
bearing and the cap to the crankcase, 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 journal of the
crankshaft, as shown in the illustration, and
subtract the diameter of the journal from the
inside diameter of the bearing (Step (1)). The
difference is the oil clearance of the main
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,
Figure 120 Fillet radius
R
3 mm
[0.12 in.]
NOTE
a Grind all crankpins to the same undersize.
b Finish the fillet radius to 3 mm [0.12 in.]
Figure 121 Measuring main bearing
Measuring diagram
Tightening torque
83 ± 5 N·m
(8.5 ± 0.5 kgf·m)
[61 ± 4 lbf·ft]
Figure 122 Measuring journal
Measuring
points
Measuring
directions
Item
Nominal
Value
Assembly
Standard
Repair
Limit
Diameter of
journal
(standard)
65
[2.56]
64.965 to 64.985
[2.5577 to
2.5585]
__
Oil clearance __
0.035 to 0.100
[0.0014 to
0.0039]
0.200
[0.0079]