Figure 14-43. Conneting Rod, Crankshaft End

TM-5-6115-545-34 Generator Set Diesel Engine Driven Tactical Skid Mtd. 30 Kw 3 Phase 4 Wire 120/208 and 240/416 Volts Manual
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Figure 14-43. Conneting Rod, Crankshaft End Avoid causing nicks and other physical damage to the I-beam section of the connecting rod. Do not clamp I-beam section of rod in a vise. Whenever connecting rod is clamped in a vise, use lead jaw protectors and clamp rod on the crankshaft end only. f. Measure outside diameter of the piston pinto determine amount of wear. Outer diameter of a new pis- ton pin is 1.5011 to 1.5013 inches. The bore of the con- necting rod bushing is 1.5027 to 1.5032 inches. These dimensions of pin and bushings provide a running clear- ance of 0.0014 to 0.0021 inch. Replace the connecting rod bushing if clearance exceeds 0.002 inch. g. Inspect connecting rod for cracks by the mag- netic particle wet fluorescent continuous method. h. Magnetization must be performed longitudinally (between the heads) using a minimum current of 2000 amperes and, transversely, (in the coil) using a minimum current of 800 amperes. A minimum of two applications of current of approximately one-half second duration in each position should be made. Apply indicating solution gently and uniformly to all portions of the part while the magnetizing current is flowing. i. Inspect the threads of connecting rod and lock bolts. If damaged, they must be replaced. j. Check the alignment, length and twist of connect- ing rod, using a checking future. The checking fixture must fist be calibrated as follows: (1) Select a new connecting rod that has been checked for correct nominal length of 8.500 inches. The length of new connecting rod (center-to-center of bores) is 8.498 to 8.502 inches. (2) Lubricate threads of connecting rod bolts with engine oil and assemble cap to connecting rod. Tighten bolts alternately to torque of 80-85 foot-pounds. (3) Install pin and crank mandrels in connecting rod. Center crank mandrel in crankshaft end so the expanding pin is located in bottom of bore near the center of rod cap. Tighten expanding pin snugly. (4) Place rod with mandrels in checking future. (5) Adjust dial indicators until their hands move approximately on revolution while resting on pin mandrel. (6) Adjust indicator faces to zero. (7) Remove connecting rod and mandrels as an assembly from checking fixture, turn rod horizontal y 180° and carefully place back in future. Readjust indica- tor faces so the zero position is halfway between original zero and reading and the new reading. The fixture is now calibrated. (8) Carefully remove connecting rod and man- drels as an assembly from checking future. k. Check connecting rod alignment as follows: (1) Lubricate threads of connecting rod bolts with engine oil and assemble cap to connecting rod that is to be checked. Tighten bolts alternately to specified torque of 80 to 85 foot-pounds for socket head capscrews or 65 to 65.5 foot-pounds for 12 point capscrews. (2) Install pin and crank mandrels in connecting rod. Center crank mandrel in large bore so the expanding pin is located in bottom of bore near the center of rod cap. Tighten expanding pin snugly. (3) Carefully place rod with mandrels in check- ing fixture and record indicator readings. (4) Remove connecting rod and mandrels as an assembly from checking fixture; turn rod horizontally 180° and carefully replace in future. Record the new indicator readings. (5) The maximum allowable bend in the rod is a combined total gauge reading of 0.004 inch. Calculate the differences in the individual indicator gauge recorded readings between step (3) and (4) above. Then add the two to get the combined total gauge reading. Change 12 14-89

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