Nanni N4.40, Workshop Manual

Page: 163 / 175

ENGINE
03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
1-S93
Oil Clearance between Crankpin and Crankpin Bearing
1. Clean the crankpin and crankpin bearing.
2. Put a strip of Plastigage on the center of the crankpin.
3. Install the connecting rod cap and tighten the connecting rod
screws to the specified torque, and remove the cap again.
4. Measure the width that it becomes flat with the scale to get the
oil clearance.
5. If the oil clearance is more than the allowable limit, replace the
crankpin bearing.
6. If the same dimension bearing is not applicable because of the
crankpin wear, replace it with an undersize one. Refer to the
table and figure.
NOTE
• Do not put the Plastigage into the crankpin oil hole.
• When you tighten the connecting rod screws, do not move
the crankshaft.
(Reference)
• Undersize dimensions of crankpin
M00000003ENS0138US1
Oil clearance between
crankpin and crankpin
bearing
Factory spec.
0.025 to 0.087 mm
0.00099 to 0.0034 in.
Allowable limit
0.20 mm
0.0079 in.
Crankpin O.D. Factory spec.
46.959 to 46.975 mm
1.8488 to 1.8494 in.
Crankpin bearing I.D. Factory spec.
47.000 to 47.046 mm
1.8504 to 1.8522 in.
Undersize
0.2 mm
0.008 in.
0.4 mm
0.02 in.
Dimension A
3.3 to 3.7 mm radius
0.13 to 0.14 in. radius
3.3 to 3.7 mm radius
0.13 to 0.14 in. radius
*Dimension B
1.0 to 1.5 mm relief
0.040 to 0.059 in. relief
1.0 to 1.5 mm relief
0.040 to 0.059 in. relief
Dimension C
46.759 to 46.775 mm dia.
1.8409 to 1.8415 in. dia.
46.559 to 46.575 mm dia.
1.8331 to 1.8336 in. dia.
The crankpin must be fine-finished to higher than Rmax = 0.4S
*Holes to be de-burred and edges rounded with 1.0 to 1.5 mm
(0.040 to 0.059 in.) relief.
KiSC issued 06, 2009 A