Oil pump

[Gkm24]

I recently rebuilt my engine at great cost and am still doing some fine tuning. All is good but the Oil pump is leaking and the pressure seems a bit low when warm. The pump is a county pump.
I am going to plug my oil pressure tester in to double check the pressure as the gauge was an ebay purchase and I don't know how accurate it is.
Is there another/Better source for oil pumps?
Any advice greatly appreciated

[simontink]

EJ Ward are the only people selling a standard pressure pump as far as I know.

http://www.ejward.co.uk/new-parts/engine-gear-box-and-servicing/engine-and-service-parts/oil-pump-standard.html

[Gkm24]

Thank you.

[72BLUE]

I recently rebuilt my engine at great cost and am still doing some fine tuning. All is good but the Oil pump is leaking and the pressure seems a bit low when warm. The pump is a county pump.
I am going to plug my oil pressure tester in to double check the pressure as the gauge was an ebay purchase and I don't know how accurate it is.
Is there another/Better source for oil pumps?
Any advice greatly appreciated

Did you put the old original spring into the new County pump? If not, do a forum search for details..........

Cheers
Keith

[marshman]

Did you put the old original spring into the new County pump? If not, do a forum search for details..........

Cheers
Keith

The problem with the County pump is usually high pressure not low pressure.

As far as I know County are the only people still making a new Stag pump. Many people recommend trying to find an original Holborn Eaton pump in good condition and fitting that, or reconditioning an Holborn Eaton pump. Having said that many people are running the County Pump with a different pressure relief spring without problem.

"Dasadrew" recently posted about the poor machining of the County pump and also about damaged O ring seals. Do a quick search and you will find it. Check yours for the issues highlighted.

Just found it - here is the link:

http://socforum.com/forum/showthread.php?31806-County-vs-Hobourn-Oil-Pumps&highlight=pump

Roger

[flying farmer]

When you say the pressure is a bit low when warm, what pressure at what revs?

45psi at about 2500rpm is about right when the engine is up to temperature, assuming you are using a good quality 20/50 oil.

15-20 psi at idle is not uncommon even when everything in the engine is in good order.

If the oil pressure rises quickly to say 35-40 psi but never gets any higher then the oil pressure relief valve spring is a little weak, and a thin washer behind the spring will add about 10psi.

If the oil pressure rises very slowly with revs and is still increasing after 3500 rpm, then somewhere in the engine there are excessive clearances which are letting too much oil escape. If the crank has been recently reground then the usual favourite is wear on the front jackshaft bearing.
Neil

[zeus]

Does anyone have a list / diagram of where the oil goes when it comes out of the pump and what areas of wear cause the oil pressure to drop as a result of it "leaking out" too quickly.

Just would help me understand how the oil works in the engine.

Zeus

[milothedog]

Does anyone have a list / diagram of where the oil goes when it comes out of the pump and what areas of wear cause the oil pressure to drop as a result of it "leaking out" too quickly.

Just would help me understand how the oil works in the engine.

Zeus

Here you are:


Oil ways.jpg

[zeus]

Thanks for that.
So assuming the pickup, pump and filter are all good then if there is low hot oil pressure it can only be the crank shaft, jack shaft or cam shaft bearings being worn. I suppose the chain tensioners could also be over leaky but that sounds unlikely?

[milothedog]

Thanks for that.
So assuming the pickup, pump and filter are all good then if there is low hot oil pressure it can only be the crank shaft, jack shaft or cam shaft bearings being worn.

I suppose the chain tensioners could also be over leaky but that sounds unlikely

?

Not unknown for them to be loose and leak between the block and tensioner body.

Ian.

[Gkm24]

Thanks for the info on this. I will double check the oil pressure this week as I have just replaced the water transfer cover gaskets as they were weeping a little.
Now that they are done, I will carry on testing it. I think that the pressure when cold is about 45-50psi and about 15 when hot but the Smiths oil pressure gauge seems a bit"sticky".