Inspection - TM-55-1930-208-240291

TM 55-1930-208-24

4-13. MAIN BEARINGS - Continued.

c. Inspection - Continued.

NOTE

Do not replace one main bearing shell alone. Always install all new

upper and lower bearing shells. If a replacement crankshaft is

being installed, install all new bearing shells.

(5) Use soft plastic measuring strip squeezed between journal and bearing, check for proper clearance.

Clearance should be .0014 inch to .0044 inch with new parts.

NOTE

If clearance between any crankshaft journal and its bearing shell

exceeds .0060 inch, all bearing shells must be discarded and

replaced.

(6) Inspect crankshaft thrust washers for signs of scoring or wear. Replace damaged thrust washers.

NOTE

Before installing new replacement bearings, it is very important to

thoroughly inspect the crankshaft journals. Refer to paragraph 4-15

for inspection of crankshaft and removal of ridges.

d. Installation.

(1) Refer to figures 4-44 and 4-43 and apply clean engine oil (item 8, Appendix C) to each crankshaft journal.

(2) Install upper main bearing shells first. Start the plain end of bearing shell around crankshaft journal so that,

when the bearing is in place, the tang will fit into the groove in the bearing support.

NOTE

The upper bearing shell is grooved and drilled for lubrication and

the lower bearing shell is not. Be sure to install the grooved

and drilled bearing shells in the cylinder block and the plain

bearing shells in the bearing caps .

(3) Install lower bearing shell so that the tang on the bearing fits into the groove in the bearing cap.

(4) Assemble the crankshaft thrust washers (4) before installing the rear main bearing cap. Slide the upper halves

of the thrust washers into place. Then, assemble the lower halves over the dowel pins in the bearing cap.

4-58