TM  10-3930-638-24&P 4-2.   ENGINE   MAINTENANCE   (cont) d. Crankshaft and Main Bearings (cont). STEP LOCATION ITEM ACTION REMARKS CLEANING (cont) WARNING Wear safety glasses when drying parts with compressed air. Fail- ure to do so could cause serious injury to eyes and possible blind- ness. If you hurt your eyes or if a foreign object is blown into your eyes, seek medical attention immediately. 3 All parts Clean Use cleaning solvent P-D-680. Dry thor- oughly with moisture free compressed air or clean cloths INSPECTION 4 5 Key  (10) Inspect Inspect for cracks, damage and wear. Re- place if cracked, damaged or worn Crankshaft  (8) a.  Crankshaft  overall Inspect Inspect surfaces for rough or grooved con- dition. Inspect for scoring, pits, cracks, damage, and evidence of overheating. If any of these conditions observed, replace crankshaft b. Crankshaft main Measure Use  micrometer.  Measure  front  and  rear  of bearing journals each journal. If diameters are smaller than 2.8730 inches use undersize bearing liners (0.002 inch) NOTE When main bearing journals are worn more than 0.002 inch, grind undersize  to  following  dimensions: Outer  Diameter Grind Undersize (inch) to (inches) 0.002 2.2460 to 2.2470 0.010 2.2380 to 2.2390 0.020 2.2280 to 2.2290 0.030 2.2180 to 2.2190 If one or more journals are to be ground, then grind all journals. c. Crankshaft main Measure Measure 90 degrees from first measurement bearing journals for  out-of-roundness.  If  out-of-roundness exceeds 0.0005 inch, regrind journal and use undersize liners. d. Crankshaft connect- Measure Use micrometer. Measure front and rear of ing rod journals each journal, checking taper. If taper ex- ceeds  0.001  inch,  regrind  journal 4-28