High Oil pressure and relief valve spring

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SJW
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High Oil pressure and relief valve spring

Post by SJW »

Hi

I know it's an unusual problem for a Rover v8 but i am concerned at too high oil pressure!

I have an SD1 front cover with distributor driven oil pump. Newly rebuilt engine, with top hat liners, new camshaft, new pistons, new oil pump gears etc. All runs and sounds like clockwork. I originally but VR 20-50 oil in but because of the problem described below i switched to mobil 10-40 but still have problem.

When cold my oil pressure is off the gauge at >80psi according to electrical gauge. Once warmed after say 15 minutes, it reduces to 35 at idle and 50-55psi at 3000-3500rpm which i am ok with. When cold i was wondering if oil pressure relief valve is sticking closed. i have removed valve plunger and spring, which seemed to be free moving. Bought a replacement kit from Rimmers and whilst valve appears to be identical the replacment spring is 81mm compared to the original one which is 71mm. i think Rimmer's spring is the uprated one and obviously i dont want to raise my oil pressure (although i assume even uprated wouldn't allow >80psi??).

1. any suggestions?
2. does anyone know if standard spring is 71mm and if so where i can buy one as no-one seems to sell them?
3. perhaps it's teh gauge but then readings when warm seem good?

thanks
Stu



SJW
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Re: High Oil pressure and relief valve spring

Post by SJW »

As a follow up Rimmers are recommending I use BH1348 which is the MGBV8 spring. The spring is definitely shorter but seems odd suggetsion as the MGb front cover is different with a remote oil filter i definetly have SD1/Vitesse front cover.

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ChrisJC
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Re: High Oil pressure and relief valve spring

Post by ChrisJC »

That does sound exceptionally high!!

I forget where the return path is for the overflow - I wonder if there is a blockage there, so the valve is opening, but the oil still can't escape.

Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8

SJW
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Re: High Oil pressure and relief valve spring

Post by SJW »

Sorted!

against logic and what I have seen posted on other forums the shorter (71mm) spring is actually the high pressure upgrade and the longer 81mm is the standard one. I think someone had fitted the upgrade/higher pressure to my cover in attempt to raise idle pressure on worn engine. As i rebuilt with new top-hat block, pistons, camshaft, rockers etc with probably had better machining tolerances and higher pressures than an original engine the upgraded spring became an problem.

81mm "standard" spring fitted and all good, even when cold max pressure 60psi vs previous 80+psi. luckily engine has never been revved until everything thoroughly warm but now one less thing to worry about.

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