TM 5-3895-383-24The two piece pistons consist of an alloy steel crownconnected to an aluminum skirt by the piston pin. Pistoncooling jets in the cylinder block spray oil to the underside ofthe piston crown to cool the piston. All three rings are locatedin grooves in the piston crown. Holes in the oil control (lower)ring groove allow oil to return to the crankcase.The connecting rod has a taper on the pin bore end. Thisgives the rod and piston more strength in the areas with themost load. Two bolts hold the rod cap to the rod. This designkeeps the rod width to a minimum, so that the rod can beremoved through the cylinder.CrankshaftThe crankshaft changes the combustion forces in the cylinderinto usable rotating torque which powers the equipment. Avibration damper is used at the front of the crankshaft toreduce torsional vibrations (twist on the crankshaft) that cancause damage to the engine.The crankshaft drives a group of gears on the front of theengine. The gear group drives the oil pump, camshaft,governor, and the gear driven air compressor and/or powersteering pump. In addition to this, the front belt pulleys on thecrankshaft drive the radiator fan, water pump, alternator andfreon compressor.Hydrodynamic seals are used at both ends of the crankshaft tocontrol oil leakage. The hydrodynamic grooves in the seal lipmove lubrication oil back into the crankcase as the crankshaftturns. The front seal is located in the front housing. The rearseal is installed in the flywheel housing.Schematic Of Oil passages In Crankshaft (4 cylinder)Schematic Of Oil Passages In Crankshaft (6 cylinder)Pressure oil is supplied to all main bearings through drilledholes in the webs of the cylinder block. The oil then flowsthrough drilled holes in the crankshaft to provide oil to theconnecting rod bearings. The crankshaft is held in place byseven main bearings. A thrust main bearing next to the rearmain bearing controls the end play of the crankshaft.6-24
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
