Nanni N4.40, Workshop Manual

Page: 162 / 175

ENGINE
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S92
(4) Crankshaft
Side Clearance of Crankshaft
1. Set a dial indicator with its point on the end of the crankshaft.
2. Move the crankshaft to the front and rear to measure the side
clearance.
3. If the measurement is more than the allowable limit, replace the
thrust bearings.
4. If the same dimension bearing is not applicable because of the
crankshaft journal wear, replace it with an oversize one. Refer
to the table and figure.
(Reference)
• Oversize dimensions of crankshaft journal
M00000003ENS0136US1
Crankshaft Bend
1. Hold the 2 end journals of crankshaft with V blocks on the
surface plate.
2. Set a dial indicator with its point on the middle journal.
3. Turn the crankshaft slowly and read the variation on the
indicator.
4. If the measurement is more than the allowable limit, replace the
crankshaft.
M00000003ENS0137US1
Side clearance of
crankshaft
Factory spec.
0.15 to 0.31 mm
0.0059 to 0.012 in.
Allowable limit
0.5 mm
0.02 in.
Oversize
0.2 mm
0.008 in.
0.4 mm
0.02 in.
Dimension A
54.50 to 54.70 mm
2.146 to 2.153 in.
54.60 to 54.80 mm
2.150 to 2.157 in.
Dimension B
26.20 to 26.25 mm
1.032 to 1.033 in.
26.40 to 26.45 mm
1.040 to 1.041 in.
Dimension C
2.8 to 3.2 mm radius
0.11 to 0.12 in. radius
2.8 to 3.2 mm radius
0.11 to 0.12 in. radius
The crankshaft journal must be fine-finished to higher than Rmax = 0.4S
Crankshaft bend Allowable limit
0.02 mm
0.0008 in.
KiSC issued 06, 2009 A