TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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c. Crankshaft. Remove crankshaft oil retaining plugs following instructions which accompany figure 6-33. Remove 1. Remove six cotter pins (A). 2. Remove six bolts (B), slotted nuts, and flat washers. 3. Remove 12 retaining plugs (C) from each end of the bore through the six crankshaft connecting rod jour- nals. Install 1. position 12 retaining plugs (C) in each end of the bore through the six crankshaft connecting rod journals. 2. Install six bolts (B), slotted nuts, and flat washers securing plugs. 3. Install six cotter pins (A) securing slotted nuts. Figure 6-33. Removing or installing crank- shaft oil retaining plugs. Note. Do not remove dowel pins (18, fig. B-3) and straight pins (25) from crankshaft unless inspection (para 6-16) indicates replacement is necessary. Dowel pins in flywheel end are secured with setscrews. 6-16. Cleaning and Inspection a. Cleaning. Refer to paragraph 6-2. Clean crankshaft oil passages with compressed air and brass wire probes. Note. Care must be taken not to destroy or remove main and connecting rod bearing location markings. b. Inspection of Crankshaft. (1) Inspect crankshaft for cracks with magnetic particle inspection equipment or similar equipment when available. When magnetic particle inspection equipment is not available use a magnifying glass (five power magnification minimum) and a strong light or dye check method. Pay particular attention to areas around crankshaft oil holes and fillets adjacent to the crank cheeks. (2) Inspect connecting rod journal radii of crankshaft for evidence of specific points of wear or damages that would indicate a bent or twisted connecting rod. (3) Check diameters of main bearing and connecting rod journals against limits specified in overhaul standards (table 6-9). Check run-out of crankshaft by supporting end journals in “V” blocks and measuring the run-out at the center journals with a dial indicator. Maximum allowable run-out is 0.025 inch at No. 4 journal. (4) Inspect journals for nicks, burs, grooves. scratches, galling, scuffing, or discoloration. Mark minor defect areas for future repair. (5) Check dowel pins and straight pins for tightness in the crankshaft flanges. Check pins against limits specified in the overhaul standards (table 6-9). c. Inspection of Connecting Rods and Bearings. (1) Connecting rod bearings. Inspect connecting rod bearing halves (fig. 6-31) in the same manner as described for main sleeve bearings. Apply a thin coating of Prussian blue, FSN 8010-247-8706, to the backs of the con- necting rod bearings and install in their respective connecting rods and caps according to the location markings (fig. 6-31). Assemble rod and cap, and torque tighten nuts to 950-pound- inches. Check bearing inside diameter, using a dial indicator as shown in figure 6-34, against the limits specified in the overhaul standards (table 6-9) for contact as shown by Prussian blue, FSN 8010-247-8706, transfer in the same manner in which the main sleeve bearings were checked (para 6-9d). Replace any bearing that does not make at least 75 percent contact. (2) Connecting rod assembly. (a) Check connecting rod bearing bore with a dial indicator against limits specified in overhaul standards (table 6-9). (b) Check rods for cracks and for twisted or bent condition. Bent or twisted connecting rods must be replaced. Under no circumstances should connecting rods be straightened. Destroy any rod found damaged to insure it will not be reused in an engine. (c) Inspect for sharp corners at rod bolt counterbore and contour areas (fig. 6-35). Mark rods having sharp corners for repair. 6-36