Detroit Diesel 4000 Series, Service Manual, Page: 400 / 2706

SERIES 4000 12/16V SERVICE MANUAL
10. Visually inspect crankshaft webs and connecting rod guide surfaces for irregularities.
[a] If irregularities are found, polish crankshaft webs and connecting rod guide surfaces.
[b] If no irregularities are found, continue inspection.
11. Inspect crankshaft taper for any traces of corrosion or minor scoring.
[a] If corrosion or minor scoring is found, polish crankshaft taper.
[b] If no corrosion or minor scoring is found, continue inspection.
12. Test the threaded bores at driving and gear case ends of crankshaft with new bolts to
ensure that bolts move easily in bores.
13. Remove cold welds by polishing.
14. Crack-test crankshaft gear, particularly gear tooth surfaces.
15. Visually inspect gear tooth surfaces for minor surface cracks (hairline cracks).
[a] If minor surface cracks are found, polish tooth surfaces.
[b] If no cracks are found, continue inspection.
16. Visually inspect crankshaft gear for surface or deeper fissures.
[a] If several surface or deeper fissures are found, replace crankshaft gear.
[b] If no fissures are found, continue inspection.
17. Visually inspect crankshaft gear for individual scores.
[a] If individual scores are found, remove by polishing the gear.
[b] If several scores are found, replace the gear.
[c] If no scores are found, continue inspection.
NOTE:
Never use a wire brush.
Checking Crankshaft for Cracks
Perform the following steps to check crankshaft for cracks:
1. Visually inspect counterweight mating surfaces (2) for wear.
[a] If counterweight mating surfaces are worn, machine-grind.
All information subject to change without notice.
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