Genuine 1994 Mazda RX-7 Oil Pump

1994 Mazda RX-7 Oil Pump Parts and Q&A

• Q: How can the oil pump be replaced or overhauled on 1994 Mazda RX-7?

  A: The oil pump may be either changed to a rebuilt pump or it may be overhauled using new components and installed back to the engine. The RX-7 oil pump has two rotor sets in it that are non-interchangeable and all parts should be separated during dismantling. The work can be started by loosening the snap ring on the shaft on the back of the oil pump and then the pump can be inverted until the rear rotor assembly is free to fall out. With needle nose pliers, take off the small keys on the exposed oil pump shaft and then take out with the screwdriver, small set screw that connects through the pump housing to the middle plate. When the set screw is taken out the middle plate and the front rotor assembly will drop off the end of the shaft. Take the pump body shaft out and soak the key, and when you have cleaned everything very well, be careful not to confuse the parts and misplace them. Install either of the rotor assemblies onto the shaft one at a time and install in the pump body, and check the clearance between the lobes of the inner and outer rotors with a feeler gauge; when the clearance is more than 0.006 in (0.15 mm), it is time to replace the rotors. Another thing is to examine the clearance between the outer rotor and the pump body; any amount over 0.0118 in (0.30 mm) would require the replacement of the rotor or the pump body. Install the inner rotor tally marks to face the rear of the pump prior to the complete assembly of the pump The front rotor assembly should first be installed on the keyed shaft with the tally marks on the inside and outside rotors aligned. The third step is to fit the middle plate to the pump body with the set screw fitting into the recess area on the middle plate and then fit the set screw and hammer and chisel the set screw in place to make sure that it does not loosen. Next, fit the key to the shaft followed by the rear side rotor assembly and again align the tally marks on the inner and outer rotors so that they face the rear of the oil pump. Lastly, screw on the snap ring to the end of the shaft, fill the pump with engine oil and fit.