CLEANING AND INSPECTION
1. Clean and inspect all parts IAW General Maintenance Instructions (WP 0019).
2. Inspect cylinder head for cracks or wear and replace if necessary.
3. Use air pressure to test water jacket of cylinder block for leaks. Replace if necessary.
4. Inspect end covers for cracks or damage and replace as necessary.
5. Inspect ball bearings for wear or flat spots. Replace bearings if worn. Check ball bearing fit in crankcase.
Bearings must be a finger-press fit. If crankcase bearing bores are worn or damaged, replace crankcase.
6. The dimension from top of cylinder block to inlet valve seat should not exceed 0.113 in. (2.87 mm) and not be
less than 0.101 in. (2.56 mm).
7. Inspect crankshaft threads, keyways, tapered ends, and all machined surfaces for wear, scores, or damage.
Replace if necessary.
8. Inspect pistons for scores, cracks, or enlarged ring grooves and replace if necessary. Measure each piston
with a micrometer in relation to the cylinder bore diameter to be sure the diametrical clearance is between
0.002 in. (0.050 mm) minimum and 0.004 in. (0.101 mm) maximum.
9. Check fit of wrist pin to piston and connecting rod. Wrist pin should be a light press fit in the piston. If loose,
replace piston and pin. Check wrist pin in connecting rod. The clearance should not exceed 0.0007 in.
(0.0177 mm); replace if excessive. Wrist pin bushings should be reamed to between 0.5314 in. (13.49 mm)
and 0.5317 in. (13.50 mm) after being pressed into connecting rods.
10. Check the fit of the piston rings in the piston ring grooves. Check the ring gap with the rings installed in the
cylinder bores. Refer to Figure 6 for correct gap and groove clearances.
Figure 6. Correct Piston Ring Groove Clearance.
11. Inspect connecting rod bearing inserts, connecting rod, and wrist pin bushing for wear or damage. Replace as
12. Inspect discharge valves for leakage by applying 100 lb (45.36 kg) of air pressure through discharge port of
cylinder head and applying soap solution to discharge valves and seats. A slight leakage in the form of soap
bubbles is permissible. If excessive leakage is found, leave air pressure applied and, using a fiber or hardwood
dowel and a hammer, tap the discharge valves off their seats several times. This will help seat the valves and
should reduce leaking on properly reconditioned valves. No leaking is allowed at the discharge valve stops
exposed on the top of the cylinder head casting.
13. Inspect cylinder bore clearance between pistons and cylinder bores. Clearance should be between 0.002 in.
(0.101 mm) minimum and 0.004 in. (0.101mm) maximum.
END OF TASK