Inspection

Fig. 19 Oil pump. 6-225:

Engine oiling system. 6-225:

6-225
To disassemble, remove the pump cover seal ring. Press off the drive gear, supporting the gear to keep load off aluminum body. Remove rotor and shaft and lift out outer pump rotor. Remove oil pressure relief valve plug and lift out spring and plunger. Remove oil pressure sending unit.

Inspection
1. The rotor contact area and the bores for the shaft and valve in the pump body should be smooth, free from scratches, scoring or excessive wear.
2. The pump cover should be smooth, flat and free from scoring or ridges. Lay a straightedge across the cover. If a 0.0015 inch feeler gauge can be inserted under the straightedge, the cover should be replaced.
3. All surfaces of the outer rotor should be smooth and uniform, free from ridges, scratches or uneven wear. Discard a rotor less than 0.825 inch thick and/or less than 2.469 inch in diameter.
4. The inner rotor and shaft assembly should be smooth, free from scoring and uneven wear. Discard rotors less than 0.825 inch thick.
5. Place outer rotor in pump body and measure clearance between rotor and body. Discard pump body if clearance is more than 0.014 inch.
6. Install inner rotor and shaft in pump body. Shaft should turn freely but without side play. If clearance between rotor teeth is more than 0.010 inch, replace both rotors.
7. Measure rotor end clearance. If feeler gauge of more than 0.004 inch can be inserted between straightedge and rotors, install a new pump body.
8. The oil pressure relief valve should be smooth, free from scratches or scoring, and should be a free fit in its bore.
9. The relief valve spring has a free length of 2-1/4 inches and should test between 22.3 and 23.3 pounds when compressed to 1-19/32 inch. If not, replace the spring.

Assembly & Installation
1. With pump rotors in body, press drive gear on shaft, flush with end of shaft.
2. Install seal ring in groove in body and install cover. Tighten bolts to 95 inch lbs. Test pump for free turning.
3. Install oil pressure relief valve spring. Use new washer (gasket) and tighten plug securely.
4. If pump shaft turns freely, remove pump cover and outer rotor before installation of pump on engine.
5. Install oil pressure sending unit and tighten to 60 inch lbs. (5 ft. lbs.).
6. Using a new gasket, install pump on engine and tighten bolts to 200 inch lbs. (16 ft. lbs.).
7. Install oil filter reservoir on pump. Install filter element and tighten cover nuts to 25 ft. lbs.
8. Connect oil pressure sending unit wire.
9. Complete the installation by reversing steps as given under Oil Pump, Replace.

Fig. 20 Oil pump. V8-318:

Engine Oiling System. V8-318:

V8-318
After removing the pump from the engine, it should be disassembled, cleaned and inspected for wear.

1. To remove the relief valve, remove the cotter pin and drill a {1/8} inch hole into the relief valve retainer cap and install a self-threading sheet metal screw.
2. Clamp screw into vise and tap on housing lightly with a soft hammer to remove the retaining cap, then remove the relief valve spring and valve.
3. Remove the oil pump cover and discard the oil seal ring.
4. Remove pump rotor, shaft and lift out outer rotor.
5. Mating surface of the pump cover should be smooth. If scratched or grooved, replace the pump.
6. Lay a straightedge across the cover. If a 0.0015 inch feeler gauge can be inserted between the cover and the straightedge, replace the pump.
7. Measure thickness and diameter of outer rotor. If rotor thickness is 0.825 inch or less, or if the diameter of rotor is 2.429 inches or less, replace outer rotor.
8. If the inner rotor is 0.825 inch or less, replace the inner rotor and shaft assembly.
9. Install the outer rotor into the housing. Press rotor to one side with the fingers and measure the clearance between the rotor and body with a feeler gauge. If the measurement is 0.014 inch or greater, replace the pump.
10. Place the inner rotor and shaft into the pump. If clearance between the rotors is 0.010 inch or greater, replace the shaft and both rotors.
11. Place a straightedge across the face of the pump between bolt holes. If a feeler gauge of 0.004 inch or greater can be inserted, replace the pump.
12. Check the oil pump relief valve plunger for scoring and free operation in the bore. Small marks may be removed with 400-grit sand paper.
13. The relief valve spring should have a free length of 2-1/32 to 2-3/64 inch and should test between 16.2 and 17.2 pounds when compressed to 1-11/32 inch. If not, replace the spring.