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4age Oil Pressure kit install guide

This guide below is for those whole wish to install the 4a / 7a oil pressure kit, this suits all models of A-series engines. Although written with the intention of being fitted to an unfitted pump, it can however but fitted to an existing pump while still on place by removing the sump and baffle plate for access.

Before starting

– Installing this kit requires pushing against a spring loaded retainer to remove a circlip, because of this it’s highly suggested to wear safety glasses.

Disassembly of pump

– On the oil pump body locate the oil pressure relief position, this is on the bottom diagonal and looks like a round hole with a circlip inside.

– Using a vice clamp the pump with the pressure relief facing upwards. To protect the housing soft jaws need to be used, but blocks of wood or wrapping in cardboard can work.

– Have some compression circlip pliers on the internal circlip prongs but don’t push them in yet.

– Use a round object to push the round disk in (the Spring seat) and then with the pliers push the clip in and remove.

– Once the circlip is fully removed release the pressure on the spring retainer.

– remove the spring seat but leave the piston and existing spring in place

Supplied parts install

– In the supplied kit is a secondary spring and an additional pre-load spacer.

– Slide this supplied spring into the inside of the existing oil pump pressure spring.

– Put the original spring retainer back it place as it was before removal.

– Sit the supplied spacer washer on the top of the spring retainer.


– Put the original internal circlip on the end of the pliers.

– In reverse of the disassembly push down to compress the spring again but with the new packing spacer on the outside.

– With everything compressed put the circlip back into it’s groove and release the force on the spring.

– Give the washer a good push a few times as well as the circlip to make sure it’s sitting correctly in the slot.

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