TM 5-4240-501-14PCYLINDERSBall BearingOn cast iron cylinders, change from rough stone tofinishing stone when within .0015" (.04 mm) of desiredsize, then use finishing stones. ALWAYS HONE .010"(.25 mm) or .020" (.51 mm), or .030" (.76 mm) ABOVETHE STANDARD DIMENSIONS GIVEN IN TABLE NO.1.CYLINDER FINISH AND CLEANINGThe finish resized cylinder should have a cross-hatchappearance, Fig. 3. Proper stones, lubrication andspindle speed along with rapid movement of hone withinthe cylinder during the last few strokes, will produce thisfinish. Cross-hatching will allow proper lubrication andrino break-in.Fig. 3 - Cross HatchIT IS MOST IMPORTANT THAT THE ENTIRECYLINDER BE THOROUGHLY CLEANED AFTERHONING. WASH THE CYLINDER CAREFULLY IN ASOLVENT SUCH AS KEROSENE OR COMMERCIALSOLVENT. THE CYLINDER BORE SHOULD THEN BECLEANED WITH A BRUSH, SOAP AND HOT WATER.BEARINGSBALL BEARINGTo check a ball bearing, rotate the bearing slowly byhand: if any roughness is noted, bearing should bereplaced.Wash bearing in a clean solvent. Re-oil with engine oilduring assembly.Ball bearings are a press fit on the crankshaft. If bearingis to be replaced, it should be removed in an arbor press.Fig. 4. (bearing should not be reused if removed fromcrankshaft.)NOTE: Bearing shield faces crankshaft crank pin.Fig. 4 - Removing Ball BearingsTo install, heat bearing in hot (2500 F Max.) (1200 CMax.) oil. Place crankshaft in a vise with bearing sideup. When bearing is hot it will be a slip fit on crankshaftjournal. Grasp bearing with the shield down and slide iton the crankshaft. Fig. 5. The bearing will tighten whilecooling. Do not quench.Fig. 5 - Install Ball BearingsPLAIN BEARINGSCheckingBearings should be replaced if scored or if plug gaugewill enter. Try gauge at several locations in bearing. Fig.6. See gauge listing in Table No. 3.3
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