K. CRANKSHAFT 1. Carry out visual inspection of the crankshaft for the following : Overheating of journals - indicated by • bluish brown color. Scoring marks on journals • Using magnetic crack detector, check for • cracks. 2. Place crankshaft on V-block, and check for run out on 1st and 5th bearing journals. 3. If the run out exceeds permissible limits, using a press carefully straighten the crankshaft in cold condition. 4. Check lateral and radial run out of flywheel mounting flange/ 5. Check dimensions of crankshaft main bearing and crank pin journals. (Grind if necessary, crankshaft main bearing and crank pin journals to the next under size.) If the 4th main bearing has to be ground, then 6. grind it to next oversize. 7. Always re-chamfer oil holes on journals to avoid scoring of new bearing shells. 8. Clean oil holes with wire brush. 9. Finish journals by covering with 320 grit lapping cloth of suitable width. Re-check main bearing, crank pin journal 10. dimensions and run out of crank shaft. Clean crankshaft with suitable cleansing agent. 11. NOTE Connecting rod bearing shells are precision • finished and should not be bored or scraped. NOTE Maintain correct fillet radii for journals. • Width of journals should not increase during • grinding. NOTE After grinding, re-check crankshaft for cracks • and balance. Crankshaft must always be stored in vertical • position. All machined surfaces should be greased. • CRANK BORE DIAMETER (MM) M 52.000 - 52.009 N 52.010 - 52.019 CRANK JOURNAL DIAMETER (MM) E 46.986 - 46.978 D 46.977 - 46.970 MAIN BEARING GRADE Blue Red Yellow Petrol Engine Ph-2 (CAFÉ) 73
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