T M 5 - 6 1 1 5 - 5 8 4 - 34NAVFAC P-8-622-34T O - 3 5 C 2 - 3 - 4 5 6 -2TM-0568C-34Figure 7-15. Crankshaft Pistons and Connecting Rod (Sheet 2 of 2)NOTEThe connecting rod and cap are stamped forinstallation in the proper cylinder. When re-moving piston assemblies, check the markingso each piston can be installed in the propercylinder.b. Removal (see figure 7-15).(1) Drain crankcase oil and remove oil base (1)and gasket (2) by removing screw (3), lockwasher (4)and washer (5).(2) Remove oil cup assembly (10, figure 7-19).(3) Remove cylinder head (paragraph 7-9) andremove all carbon at the top of the cylinder bore. Re-move ridge from cylinder bore before removingpiston.(4) Remove bolts (6, figure 7-15), cap (8) andbearings (7) from each connecting rod (9) and push thepiston assembly (10) upward through top of cylinderbore with a soft wooden tool to prevent rod bearingdamage. Loosely install cap (8) and bearings (7) onthe corresponding removed piston assembly to main-tain proper grouping.c. Disassembly (see figure 7-14).(1) Using a ring expander, remove piston rings(1, 2 and 4) and oil ring expander (3) from each piston.(2) Remove two retaining rings (5) and push pistonpin (6) from each piston.d. Inspect and Repair.(1) Pistons. Thoroughly clean and inspect eachpiston. Clean carbon from ring grooves and be sureall oil holes are open. If any piston is badly scoredor burred, loose in cylinders, has badly worn ringgrooves or otherwise is not in good condition, replaceit. Check the piston clearance in cylinder 90° fromaxis of piston pin and below oil control ring (4, figure7-14). Clearance should be 0.0062 to 0.0082 inch (seetable 1-2). If not, replace piston and check cylinderwall for possible reconditioning.(2) Piston Pins. Each piston pin should be athumb push fit into its piston at room temperatures.Figure 7-16. Piston Ring Installation7-17
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