TM 9-6115-604-34NAVFAC P-8-633-34(x) Using honing machine MIL-H-45583, size the new piston pin bushing (13, Figure 9-24) to an inside diameter of 2.4010to 2.4015 inches (60.985 to 60.998 mm).WARNINGDry cleaning solvent PD-680, Type III, or equivalent, is flammable and moderately toxic to theskin, eyes, and respiratory tract. Assure adequate ventilation. Skin, eye, and respiratoryprotection Is required to avoid Injury to personnel.WARNINGCompressed air used for cleaning or drying can create airborne particles that may enter theeyes. Pressure shall not exceed 30 psi (207 kPa). Wearing of goggles Is required to avoidInjury to personnel.(y)Clean the bushing and oil passage in the connecting rod thoroughly, using dry cleaning solvent P-D-680,Type 11, or equivalent, and blow dry with compressed air.(z)Re-check the connecting rod alignment in accordance with step (9), above.(11)Check the bolts and dowels as follows:(a)Check for bent or distorted bolts. The head of the connecting rod bolt (1, Figure 9-24) must rest squarelyon the milled surface of the cap (3), (see step (1), above. Replace bent or distorted connecting rod bolts.(b)If the connecting rod bolts (1) have been tightened excessively, they may be permanently stretched in thearea indicated in Figure 9-29. Replace any bolt if the smallest diameter is less than 0.600 inch (15.24mm).(c)Replace any connecting rod bolts (1, Figure 9-24) that have distorted threads.(d)Remove and discard the dowels (12), if damaged. Check the piston pin (9) outside diameter with amicrometer. Pins shall be replaced if they are out-of-round more than 0.001 inch (0.03 mm), or wornsmaller than the minimum diameter given in Table 14.(12)Check the piston pin (9) outside diameter with a micrometer. Pins shall be replaced if they are out-of-round morethan 0.001 inch (0.03 mm), or worn smaller than the minimum diameter given in Table 1-4.(13)Inspect the pistons (10) as follows:(a)Visually inspect the piston for signs of erosion, broken ring lands, visible cracks, or severe scoring.Replace defective pistons.(b)Check the piston ring grooves for wear using wear gage ST-560.If the gage shoulder touches the ringgroove lands, replace the piston.NOTEBecause aluminum pistons have a high coefficient of expansion, all measurements shall betaken at a stabilized piston temperature of 70°F (21°C).(c)Measure the piston pin bore on both sides of the piston with an inside micrometer. Replace the piston ifthe pin bore on either side is over the allowable limits given in Table 1-4.(d)Using an outside micrometer, measure the piston skirt at 90 degrees to the piston pin bore. Replace thepiston if the skirt diameter is under the limits given in Table 1-4.(e)Inspect the piston for cracks using dye penetrant MIL-1-25135 accordance with MIL-1K66. Replace anydefective pistons.9-53
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