TM 5-3805-260-24BASIC BLOCKCYLINDER BLOCKThe cylinders are a part of the cylinder block.There are no replaceable cylinder liners. The cylinderscan be machined (bored) up to .040 in. (1.02 mm)oversize for reconditioning. The cylinders in the blockare at a 900 angle to each other. There are fire mainbearings in the block to support the crankshaft.CYLINDER HEADThere is one cylinder head for each side (bank)of the engine. One intake and one exhaust valve is usedfor each cylinder. The valve guides are a part of thecylinder head and can not be replaced. A valve seatinsert is used for the exhaust valve and can be replaced.When the seat for the intake valve has been machined tothe limits given in the SPECIFICATIONS, it can be bored(machined) for a valve seat insert.PISTONS, RINGS AND CONNECTING RODSThe pistons have two rings which are locatedabove the piston pin bore. There is one compressionring and one oil control ring. The oil ring is made in onepiece and has an expansion spring behind it. Thecompression ring is also one piece and goes into an ironband that is cast into the piston.The piston pin is held in the piston by two snaprings which go into grooves in the piston pin bore.The connecting rod is installed on the piston withthe boss on the connecting rod on the same side as thecrater in the piston. The connecting rod bearings areheld in location with a tab that goes into a groove in theconnecting rod.CRANKSHAFTThe force of combustion in the cylinders ischanged to usable rotating power by the crank - shaft.The crankshaft can have either six or eightcounterweights. A gear on the front of the crank - shaftturns the engine camshaft gear and the engine oil pump.The end play of the crankshaft is controlled by the thrustbearing on No. 4 main bearing.VIBRATION DAMPERThe twisting of the crankshaft, due to the regularpower impacts along its length, is called twisting(torsional) vibration. The vibration damper is installed onthe front end of the crankshaft. It is used for reduction oftorsional vibrations and stops the vibration from buildingup to amounts that cause damage.The damper is made of a flywheel ring (1)connected to an inner hub (3) by a rubber ring (2). Therubber makes a flexible coupling between the fly-wheelring and the inner hub.CROSS SECTION OF VIBRATION DAMPER1. Flywheel ring. 2. Rubber ring. 3. Innerhub.2-18
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business