8 replies to this topic

[Rio]

I have just changed the oil pressure relief valve from a cone shaped to a ball bearing type. The ball bearing came matched with the correct spring which seemed stiffer than the old.

From cold used to get 60PSI and when engine is very hot after speed the pressure dropped to 20PSI or just under.

Now, from cold it’s reading 80-85PSI on idle. Not tested on a run yet as car is Sorned. Could well be I had a weak spring and worm valve. 

There is wear on the old cone but I am interested to know what pressure you all get on average?

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[floormanager]

Others might direct you to this thread

 

https://www.theminif...huttle-vs-ball/

 

[Rio]

Wow, that is an interesting article, thanks.

So, I am just trying to work out why the oil pressure is so much higher than what I had with the cone valve. Would it be a weak spring and worn cone and if so, would I be better for buying a new standard spring and cone. 
One last question, if I be got good oil pressure now, I presume main and big ends are OK and that it’s just the valve I’ve got to out?

Thanks again 

[GraemeC]

The 60 psi is more than enough, I’d say the new spring is too strong (apart from the other advice that the bullet is a better design).

The new arrangement won’t make any difference to the hot pressure.

 

Think about it logically - why would the pressure the old valve ‘released’ at become lower at higher all temperatures? The hot pressure is purely down to worn bearings.

[Rio]

Cheers Graeme

If I was getting 60PSI on cold but dropping to 20PSI when hot but only going up to say 30-35PSI at speed then I was presuming if the new set up gave say 20PSI higher from cold, the hit must be higher in scale.

[GraemeC]

No because the hot pressure is irrelevant of the release pressure of the valve.

 

The old valve released at 60, but the pressure never got anywhere near that when hot. So even with the new valve releasing at 80 the hot pressure will not change.

[Rio]

Thanks Graeme 

[Spider]

I've moved this to PTQ as it's a more appropriate platform for the thread.

The higher cold pressure could likely be that the spring is too long. These kits I've seen include a standard spring, which is designed for the bucket, into which it nestles well down in to, when used on a ball, it sits 'higher' and so will increase the cracking pressure at which it starts to open. The hot pressure could be as Graham suggests, poor oil choice, or just worn oil and / or worn oil pump.

 

[Rio]

Thanks Spider