REMOVAL & INSTALLATION
See Figure 1
The rotor type of pump is externally mounted on the rear right-hand (camshaft) side of the engine and is gear driven (helical) from the camshaft. The oil filter screws into the pump body.170, 198 and 225 Engines
- Remove the outer cover and catch the rotor, as it will fall. Remove oil pump mounting bolts and remove pump and filter assembly from engine.
- Disassemble the oil pump (drive gear must be pressed off) and inspect the following clearances: maximum cover wear is 0.0015"; outer rotor to body maximum clearance is 0.014"; maximum clearance between rotors is 0.010". Inspect the pressure relief valve for scoring and free operation. Relief valve spring should have a free length of 2 1 / 4 ".
- Install oil pump to engine block using a new gasket and tightening mounting bolts to 200 in. lbs.
- Install new oil seal rings between cover and body, tightening cover attaching bolts to 95 in. lbs.
- Remove the oil pan.
- Remove the oil pickup tube, strainer and all old gaskets.
- Remove the oil pump joint bolt.
- Remove the filter assembly-to-oil pump tube.
- Remove the joint bolt and remove the oil pump and gasket.
- Clean all gasket surfaces. Discard all old gaskets.
- Remove the oil pump cover.
- Remove the inner rotor and shaft assembly and lift out the outer rotor.
- Clean all parts thoroughly. Mating surfaces of the pump should be smooth. Replace the cover if it is scratched or grooved.
- Install the outer rotor into the pump body. Install the inner rotor onto the outer rotor and seat it into the pump body. Place a straight edge across the pump face. Insert a feeler gauge between the straight edge and the rotors. Clearance should be 0.035-0.095mm. If clearance exceeds 0.15mm replace both the inner and outer rotors. Check the clearance between the inner and outer rotor. Clearance should be 0.17mm or less. If clearance exceeds 0.25mm replace both the inner and outer rotors. Measure the clearance between the outer rotor and the pump body. Clearance should be 0.2-0.3mm. If clearance exceeds 0.5mm replace the outer rotor. Measure the rotor shaft OD and the pump body ID. The clearance between the shaft and the body should be 0.032-0.074mm. If clearance exceeds 0.15mm replace the inner rotor and shaft and/or the pump body.
- Replace all parts that show signs of wear.
- Assemble the pump.
- Use all new gaskets.
- Install the oil pump and gasket.
- Install the filter assembly-to-oil pump tube.
- Install the oil pump joint bolt. Torque the bolt to 39 ft. lbs.
- Install the oil pickup tube and strainer.
- Install the oil pan.
See Figures 2 through 8
It is necessary to remove the oil pan, and to remove the oil pump from the rear main bearing cap to service the oil pump.
- Drain the engine oil and remove the oil pan.
- Remove the oil pump mounting bolts and remove the oil pump from the rear main bearing cap.
- To remove the relief valve, drill a 1 / 8 " hole into the relief valve retainer cap and insert a self-threading sheet metal screw into the cap. Clamp the screw into a vise and while supporting the oil pump, remove the cap by tapping the pump body using a soft hammer. Discard the retainer cap and remove the spring and the relief valve.
- Remove the oil pump cover and lockwashers, and lift off the cover. Discard the oil ring seal. Remove the pump rotor and shaft, and lift out the outer rotor.
Wash all parts in solvent and inspect for damage or wear. The mating surfaces of the oil pump cover should be smooth. Replace the pump assembly if this is not the case.
- Lay a straight edge across the pump cover surface and if a 0.0015" feeler gauge can be inserted between the cover and the straight edge, the pump assembly should be replaced. Measure the thickness and the diameter of the outer rotor. If the outer rotor thickness measures 0.825" or less, (0.943" or less on 360 cu.in. engines 1977-88) or if the diameter is 2.469" or less, replace the outer rotor. If the inner rotor measures 0.825" or less, (0.943" or less on 360 cu.in. engines 1977-88) then the inner rotor and shaft assembly must be replaced.
- Slide the outer rotor into the pump body, do this by pressing it to one side with your fingers and measure the clearance between the rotor and the pump body. If the measurement is 0.014" or more, replace the oil pump assembly. Install the inner rotor and shaft into the pump body. If the clearance between the inner and outer rotors is 0.010" or more, replace the shaft and both rotors.
- Place a straightedge across the face of the pump, between the bolt holes. If a feeler gauge of 0.004" or more can be inserted between the rotors and the straight edge, replace the pump assembly.
- Inspect the 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.
- The relief valve spring has a free length of 2 1 / 32 -2 3 / 64 " and should test between 16.2 and 17.2 lbs. when compressed to 1 11 / 32 ". Replace the spring if it fails to meet this specification.
- To install, assemble the oil pump, using new parts as required. Tighten the cover bolts to 95 in. lbs.
- Prime the oil pump before installation by filling the rotor cavity with engine oil. Install the oil pump on the engine and tighten attaching bolts to 30 ft. lbs.
- Install the oil pan.
- Fill the engine with the proper grade motor oil. Start the engine and check for leaks.
See Figure 9
The rotor type oil pump is externally mounted and gear driven from the camshaft. The oil filters screws into the pump body.
- Drain engine oil.
- Remove oil pump and filter assembly.
- Disassemble and inspect pump components for wear. Of 0.0015" feeler gauge can be inserted between cover and straight edge, replace cover. Install outer rotor in pump body and holding against one side of body measure clearance between rotor and body. If clearance is greater than 0.014", replace oil pump body. Install inner rotor into pump body and place straight edge across pump body between bolt holes. If feeler gauge is greater than 0.004" can be inserted between rotors and body, replace oil pump body. Measure clearance between tips of inner and outer rotor where they are opposed. If clearance exceeds 0.010", replace inner and outer rotors. Use new oil seal rings between filter base and body. Tighten bolts to 10 ft. lbs. Use a new O-ring seal on pilot of oil pump before attaching pump to engine block.
- Install oil pump on engine using new gasket and tightening bolts to 30 ft. lbs. The distributor drive gear slot should parallel the crankshaft with no.1 cylinder on TDC.
- Install oil filter and fill crankcase with oil.