Detroit Diesel MBE 4000 Service Manual page 114

1.9 CRANKSHAFT ASSEMBLY
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[b] Test hardness all the way around the journal circumference. Hardness must be 53 to
59 HRC as listed in Table 1-13.
Description
Main Bearing and Connecting Rod Journal Hardness
(Rockwell hardness)
Permissible Deviation From True of Crankshaft†
Permissible Out-Of-Round for Main and Connecting-Rod
Bearing Journals - When New reground
Permissible Out-Of-Round for Main and Connecting-Rod
Bearing Journals - Wear Limit
Fillet Radii of Main Bearing Journals
Fillet Radii of Connecting Rod Bearing Journals
Crown of Main Bearing Journals and Connecting-Rod
Journals
Main Bearing Outside Diameter (diameter of bearing
shell housing
Permissible Imbalance of Crankshaft‡ -at 400 rpm
* Except as otherwise noted.
†Measure with the crankshaft mounted on the outer main bearing journals.
‡With the pin for the flywheel installed, but without the flywheel, and with the crankshaft mounted on the outer bearings.
Table 1-13 Crankshaft Specifications
5. Measure the deviation from true of the crankshaft. If the deviation from true is greater
than 0.09 mm (0.004 inch), regrind the crankshaft.
[a] Support the crankshaft on a stand, held by the two external journals.
[b] Set up a dial gauge and holder on the center journal, with some preload on the gauge.
[c] Set the dial gauge to "0" (zero).
[d] Turn the crankshaft through one full revolution, and check the dial gauge. If the dial
gauge deviates by more than 0.09 mm (0.004 inch), regrind the crankshaft.
6. Check the crankshaft for dynamic balance. Permissible imbalance is listed in Table 1-13.
7. Using a micrometer, measure the diameters of the main journals and the connecting-rod
journals. Measure in both the vertical and horizontal directions on each journal.
Refer to section 1.9.2.2 for detailed procedures.
8. Comparing the two measurements taken above, check each crankshaft main and
connecting-rod journal for out-of-round.
If, for any one journal, the two measurements differ by more than 0.01 mm (0.0004 inch), regrind
the crankshaft.
If, for any one journal, the two measurements differ by more than 0.02 mm (0.0008 inch), replace
the crankshaft. Refer to section 1.9.1.
1-66
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Specification in mm (inches)*
53 to 59 HRC
0.09 (0.004)
0.01 (0.0004)
0.02 (0.0008)
4.2-4.5 (0.165-0.177)
3.7 - 4.0 (0.146 - 0.157)
0.000-0.004 (0.0000-0.0002)
111.000-111.022 (4.3701-4.3709)
0.6 N·cm (0.05 lb·in)
6SE412 0403 Copyright © 2004 DETROIT DIESEL CORPORATION
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All information subject to change without notice.
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