Service Manual

8. Visually check surface of connecting rod bearing. Re-
place bearing if uneven, streaked, damaged or seized.
When streaks or seizure are excessive, check the
crankshaft. If crankshaft is damaged, replace crank-
shaft or machine to next undersize.
9. Measure inner diameter of connecting rod bearing
a
nd outer diameter of crankshaft pin. If the gap (oil clear-
ance) exceeds the limit, replace the bearing and/or
crankshaft or machine crankshaft to next undersize.
Use bearings to match undersize crankshaft.
NOTE: (see Crankshaft and Flywheel for measuring oil
clearance with plastic gauge method).
Guide A
Push rod
Piston pin
Piston and Connecting Rod Reassembly
Figure 205
1. Install connecting rod to piston with ”front
” identifica-
tion marks both facing the same direction (arrow mark
on piston and die mark on ”convex portion” of connect-
ing rod). Apply engine oil to piston pin and use piston pin
setting tool to install piston pin from ”front” side of piston.
Front mark
Piston pin
Front mark
Standard value 0.022 – 0.052 mm (.0009 – .0020 in.)
Limit .01 mm (.004 in.)
Piston pin setting force 5,000 – 15,000 N
(1,102
– 3,307 lbs.)
Figure 206
2. Assemble oil ring spacer into piston ring groove.
Install upper side rail first, then lower side rail. NOTE:
There is no dif
ference between upper and lower side
rails or spacers. The following identification colors are
painted on new spacers and side rails according to size.
Figure 207
Side rail
Spacer
Size Identification color
Standard None
0.25 mm (.0098 in.) O.S. Two blue lines
.050 mm (.1097 in.) O.S. One red line
.075 mm (.0295 in.) O.S. Two red lines
1.00 mm (.0393 in.) O.S. One yellow line
IMPORTANT: To install, push side rail in with your
finger as shown after fitting one end over the piston
groove. DO NOT use a ring expander. Use of a ring
expander can break the side rail. Make sure side
rails move smoothly in either direction.
Figure 208
End of side rail
Liquid Cooled Gas Engine
Page 3 – 98
Workman 3000/4000 Series