Table 9-3. Connecting Rod Bolt Tightening Sequence and Torque

Figure 9-27. Chamfering Connecting Rod Piston Pin Bore Using ST-861

TM-9-6115-604-34 Generator Set Diesel Engine Driven Tactical Skid Mtd 5 Kw. 1 Phase-2 Wire 1 Phase -3 Wire 3 Phase -4 Wire 120. 120/240 and 120/208 Volts Manual
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TM 9-6115-604-34 NAVFAC P-8-633-34 (5) Check the crankpin bore with a dial bore gage or inside micrometer. The bore diameter shall be within 4.5017 to 4.5027 inches (114.343 to 114.368 mm) in the complete circumference of the bore (B, Figure 9-26). (6) Out-of-roundness or taper in the connecting rod crankshaft bore shall not exceed 0.001 inch (0.03 mm). (7) Replace the connecting rod if the crankpin bore does not meet the specifications given in steps (5) and (6), above. (8) Gage the piston pin bushing diameter (13, Figure 9-24) with an inside micrometer or dial bore gage. The maximum bushing diameter shall be in accordance with A, Figure 9-26. Replace a worn bushing in accordance with step (10), below. (9) Check the connecting rod alignment as follows: (a) Calibrate the checking fixture ST-561 for connecting rod size as follows: 1 Select a new rod that has been checked for the correct absolute center-to-center length of 11.406 inches (289.71 mm) between centers. NOTE Production rods may vary from 11.405 to 11.407 inches (289.69 to 289.74 mm). 2 Assemble the cap to the rod as described in step (4), above. 3 Insert the piston pin, furnished in the ST-1305 Locating Mandrel Set, into the piston pin bore. 4 Insert and snug tighten the expanding arbor ST-1331 in the crankpin bore. The locking pin must face down and be on the center line of the connecting rod. 5 Set the rod in the fixture and zero the dial indicators on the piston pin. 6 Lift the rod, arbor and pin assembly from the fixture, turn it front-to-back, return it to the fixture, and record the indicator readings at the piston pin. Readjust the dial indicators to divide the difference between the zero setting and the second readings, and zero the indicators. The fixture is now calibrated. NOTE The measurements read directly from the dial indicator indicate the comparative length of the connecting rod, and misalignment of the bore. The measurements may be made without the piston pin, bushing installed. If the bushing is badly worm, remove it before checking the alignment. (b) Assemble the Locating Mandrel Set in the rod to be checked. Set the rod in the fixture, and be sure the pin in the mandrel is down and locked in position in the center line of the rod. (c) Take readings for length (compared to the length set up on calibration of fixture) and misalignment of the crankshaft and piston pin bores (the difference in the readings from one indicator to the other). Table 9-3. Connecting Rod Bolt Tightening Sequence and Torque STEP PROCEDURE FIG. TORQUE* POUND-FEET REF. Figure 9-24 (NEWTON-METERS) 1 Cross-tighten both bolts (1) 70 to 80 (95 to 108) 2 Cross-tighten both bolts (1) 140 to 150 (190 to 203) 3 Cross-tighten both bolts (1) 210 to 220 (285 to 298) 4 Loosen both bolts (1) Remove all tension 5 Repeat steps 1, 2, and 3, above. connecting rod bolts (1) shall be 210 to 220 pound- feet. (285 to 298 Newton-meters). Final torque on all *Before installing connecting rod bolts(1) and washers (2), coat bolt threads, underside of bolt heads, and washers with clean lubricating oil MIL-L-45199. 9-50

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