Oil Pump Service

Service of oil pump requires pump to be removed.
Oil Pump Replacement

Fig. 32 Oil Pump:

With pump removed, disassemble pressure relief valve by pulling out cotter pins and drilling a 1/8 in. hole into center of relief valve retainer cap. Insert a self-threading sheet metal screw into cap and secure head in vise. While supporting pump body, remove cap by tapping body with soft hammer. Discard retainer cap and remove spring and relief valve. Relief valve spring has a free length of 1.95 in. and should test between 19.5 and 20.5 lbs. when compressed to 1.34 in. Any spring that fails to meet specifications must be replaced. Unbolt oil pump cover and discard oil seal ring. Inner rotor and shaft can now be removed as well as outer rotor. Clean all parts thoroughly and inspect for damage or wear. If mating surface of oil pump cover is scratched or grooved, replace pump assembly.

Fig. 33 Oil Pump Cover Flatness Inspection:

Lay a straightedge across pump cover surface. If a 0.0015 in. feeler gauge can be inserted between cover and straightedge, replace pump assembly.

Fig. 34 Outer Rotor Thickness Measurement:

If outer rotor thickness measures 0.825 in. -or less- or the diameter is 2.469 minimum -or less- replace the outer rotor.

Fig. 35 Inner Rotor Thickness Measurement:

If inner rotor measures 0.825 in. -or less- replace inner rotor and shaft assembly.

Fig. 36 Outer Rotor Clearance In Pump Body Measurement:

With outer rotor inserted into pump body, press rotor to one side with fingers. If clearance between rotor and pump body is 0.014 in. or more, replace oil pump assembly.

Fig. 37 Clearance Over Rotor Measurement:

With inner rotor inserted into pump body, place a straightedge across face between bolt holes. If a feeler gauge of 0.004 in. can be inserted between rotors and straightedge, replace oil pump assembly.

Fig. 38 Clearance Measurement Between Rotors:

Shaft and both rotors should be replaced if tip clearance between inner and outer rotor exceeds 0.010 in.

Fig. 39 Distributor Drive Gear Position:

Using new parts as required, assemble pump. Prime pump before installation by filling rotor cavity with engine oil. Rotate engine until No. 1 cylinder is at Top Dead Center (TDC) and timing mark on damper is at zero. Coat distributor drive gear and shaft with oil, install shaft so that after gear spirals into place it will index with oil pump shaft. The slot on top of the drive gear should be aligned towards the left front intake manifold attaching bolt hole.