Inspection

1. Clean all parts thoroughly. Mating surface of the oil pump should be smooth. Replace pump cover if scratched or grooved.





2. Lay a straightedge across the pump cover surface. If a 0.076 mm (0.003 inch) feeler gauge can be inserted between cover and straight edge, cover should be replaced.





3. Measure thickness and diameter of outer rotor. If outer rotor thickness measures 9.40 mm (0.370 inch) or less, or if the diameter is 79.95 mm (3.148 inches) or less, replace outer rotor.





4. If inner rotor measures 9.40 mm (0.370 inch) or less replace inner rotor.





5. Slide outer rotor into pump housing, press to one side with fingers and measure clearance between rotor and housing. If measurement is 0.39 mm (0.015 inch) or more, replace housing only if outer rotor is in specification.





6. Install inner rotor into pump housing. If clearance between inner and outer rotors is 0.203 mm (0.008 inch) or more, replace both rotors.





7. Place a straightedge across the face of the pump housing, between bolt holes. If a feeler gauge of 0.102 mm (0.004 inch) or more can be inserted between rotors and the straightedge, replace pump assembly, ONLY if rotors are in specs.
8. Inspect oil pressure relief valve plunger for scoring and free operation in its bore. Small marks may be removed with 400 grit wet or dry sandpaper.
9. The relief valve spring has a free length of approximately 60.7 mm (2.39 inches) it should test between 18 and 19 pounds when compressed to 40.5 mm (1.60 inches). Replace spring that fails to meet specifications.
10. If oil pressure is low and pump is within specifications, inspect for worn engine bearings or other reasons for oil pressure loss.