Inspection

100 Oil Pump:

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

Checking Oil Pump Cover Flatness:

2. Lay a straightedge across the pump cover surface. If a 0.025 mm (0.001 inch) feeler gauge can be inserted between cover and straight edge, cover should be replaced.

Measureing Outer Rotor Thickness:

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 inch) or less, replace outer rotor.

Measuring Inner Rotor Thickness:

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

Measuring Outer Rotor Clearance In Housing:

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.

Measureing Clearance Between Rotors:

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.

Measuring Clearance Over 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.