Oil Pump Overhaul

[V Mad]

I have fitted new O-rings to the oil pump (part of bottom end gasket set). AfterI replaced the cover, and tightened the two screws, the pump was very tight to turn. When I loosened the cover itwas free to turn.

What seems to be happening is that the O-ring is too thick, and binds on the pump rotor.

My only option now seems to be to get a thinner O-ring; I am not happy to risk heavily loading up the pump drive shaft as this puts a load on the jackshaft spiral gear.

Has anyone else had this problem?

[Andrew S]

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Hi Chris

I did mine about 2 years ago and got my seals from LDPart and did not have a problem. I think the O rings flatten after a short time which would help your case, but I agree that you dont want to put any load on the pump at any time.

Where did you buy them from and is the engine out of the car for easy access?

Andrew

[V Mad]

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Hi Andrew

Yes the engine is out for rebuild. The O-rings were in a gasket set; I dont think these sets are very good on critical parts. I think I will get some from Peter at LD.

[Andrew S]

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If you do, I think he does a kit that does the O ring for the oil swicth transfer housing as well

[jleyton]

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Hi Chris,

I'm just overhauling my pump right now and when I read your post I went and screwed mine together with the O ring in place and it turns freely This was with an oil pump O ring kit from Peter at LD.

Just a thought - I also bought the transfer housing kit from Peter which is just the 2 O rings. The large one is almost the same size as the oil pump one but fractionally smaller diameter and thicker cross section. As your came as part of a bottom end kit, I wonder if those two got muddled up, or your supplier only included the transfer housing one?

Cheers

Julian

[V Mad]

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By luck I had an O-ring in my spares box which I tried and this seems to fit perfectly. Whenthe cover is tightened down, the pump still turns freely.

The O-ring measures 1.8mm thick (which is close toa BS standard thickness 1.78mm), and the recess in the pump is 1.4mm, so I am happy that it will not leak.

If you are doing an oil pump, be careful to fit the right O-ring.

[jleyton]

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So, do you think your first O ringcould have been what I suggested then Chris ?

Cheers

Julian

[V Mad]

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I think that what has happened is that the gasket set supplied the (thicker) O-ring that goes between the block and oil pump but not the (thinner) internal pump O-ring. Seems odd to me, but the internal one was apparentlymissing; for the sake of one O-ring you cannot finish the job

[jbuckl]

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I glibly bought a new pump to stop a leak......mistake.

It leaked worse than ever from the relief valve cap.

Took it apart only to find the 'new' o-ring was shredded because it was too thick!

Seems you cant rely on new parts or gasket kits.

Seems as if only LD spares do the right thing?