572 / 1906
ENGINE
140
Crank Shaft :
Clean and carry out visual inspection of crank
shaft for the following:
1. Overheating of journals, this is indicated by
bluish brown colour.
2. Scoring marks on journals
3. Cracks, which should be checked on
magnetic crack detector
4. Check crank shaft run out by supporting it on
V-block at 1st and 3rd main bearing journals.
5. If run out exceeds permissible limits,
straighten crank shaft in cold condition on
press carefully.
6. Similarly check lateral and radial run outs of
flywheel mounting flange.
7. Check crank shaft main bearing and crank pin
journal dimension.
8. Record the readings in the format given at the
end of this group.
9. If necessary, grind crank shaft main bearing
and crank pin journals to next under-size.
10. Maintain correct fillet radius for journals
11. Care must be taken during grinding to ensure
that width of journals is not increased.
12. Should it be necessary to grind sides of 4th
main bearing journal, grind it to next
undersize.
13. Re-chamfer oil holes on journals to avoid
scoring of new bearing shells.
14. Finish journals by lapping them with 320 grit
lapping cloth of suitable width.
15. After grinding recheck main bearing and crank
pin journal dimensions.
16. Also recheck run out of crank shaft.
17. Thoroughly clean crank shaft with kerosene.
Use wire brush for cleaning oil holes.
NOTE
It is essential to recheck crank shaft for
cracks and balance after grinding.
18. Apply grease to all machined surfaces, if
crank shaft is to be stored. Crank shaft must
always be stored in vertical position.
19. Thoroughly clean main bearing caps and
corresponding
machined
surfaces
of
crankcase.
20. Install main bearing caps without bearing
shells in their respective positions on
crankcase.
NOTE
Ensure that the serial numbers on crank
case and main bearing caps are matching.
Also caps are in order and notches
forbearing shells are on same side.