Oil Pump
INSPECTION AND REPAIR1. Clean all parts thoroughly. Mating surface of the oil pump housing should be smooth. Replace pump cover if scratched or grooved.
Fig. 111
2. Lay a straightedge across the pump cover surface (Fig. 111). If a 0.025 mm (0.001 inch) feeler gauge can be inserted between cover and straight edge. cover should be replaced.
Fig. 112
3. Measure thickness and diameter of outer rotor. If outer rotor thickness measures 9.474 mm (0.373 inch) or less (Fig. 112), or if the diameter is 89.174 mm (3.5108 inches) or less, replace outer rotor.
Fig. 113
4. If inner rotor measures 9.474 mm (0.373 inch) or less replace inner rotor (Fig. 113).
Fig. 114
5. Slide outer rotor into body, press to one side with fingers and measure clearance between rotor and body (Fig. 114). If measurement is 0.39 mm (0.015 inch) or more, replace body only if outer rotor is in specifications.
Fig. 115
6. Install inner rotor into body. If clearance between inner and outer rotors (Fig. 115) is 0.20 mm (0.008 inch) or more, replace both rotors.
Fig. 116
7. Place a straightedge across the face of the body, between bolt holes. If a feeler gauge of 0.077 mm (0.003 inch) or more can be inserted between rotors and the straightedge, replace pump assembly (Fig. 116) 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 49.5 mm (1.95 inches) it should test between 23 - 25 pounds when compressed to 34 mm (1.34 inch). Replace spring that fails to meet specifications.
OIL PUMP ASSEMBLY
1. Assemble pump, using new parts as required.
2. Tighten cover screws to 12 Nm (105 in. lbs.).
3. Prime oil pump before installation by filling rotor cavity with engine oil.
4. If oil pressure is low and pump is within specifications, inspect for worn engine bearings or other reasons for oil pressure loss.