Oil Pressure Relief Spring - Very Useful Tip
Discussion
Thought I'd shout this one as I've just come back from a test drive in the Cerb.
Always had an oil pressure 40-50psi cold down to 30-40psi hot and as low as 25-30psi hot idle. Its been spoken about a number of times on this board and at meets. Most people agreed that it was similar to theirs, Cerb oil pressure gauge unreliable, or reassured because its always been that way over the eight months ownership and no sudden drop in pressure.
Also always had a poor reading on the fuel gauge which means it runs out of petrol when indicating 1/4 full. So okay I thought probably similar unreliable gauge, keep an eye on it and be reassured by its constant nature.
Recently I installed a lift into my garage, and for want of something better to do I looked for the oil pressure relief valve. Once located I removed the spring which was in good condition no sign of damage and difficult to compress between fingers.
I looked back at the car and for reasons I can't explain now decided against any evidence to replace it. I went and got one from Walldonway. To my horror when I matched up the springs the one from my car was about half a centimetre shorter than the new one. I tested them both on my home press and the new one was also considerably stronger.
I fitted the new one in the car and to my horror the idle psi went immediately to 80psi cold. I took the car on my normal 'go to work' journey for comparison. Not only did the engine noise die down in half the time it normally would, but even hot the gauge didn't go below 60psi and on hot idle 45-50psi. Thats another 20psi at the camshaft!!! Even my idle camshaft noise is noticeable less.
From this I think we should all review the advice to 'sit and watch'. I can't believe the spring isn't mentioned on any service shedule, although it is a known wear part for Cerbs, Walldonway weren't even surprised by my tale. I for one will be changing that spring yearly.
It cost me £4, and took me less than five minutes to do, and has probably saved me a considerable amount of future engine wear.
I would be happy to talk anyone through it, post piccies etc, or even point it out to you if you stray past brands hatch
DON'T WAIT.
Always had an oil pressure 40-50psi cold down to 30-40psi hot and as low as 25-30psi hot idle. Its been spoken about a number of times on this board and at meets. Most people agreed that it was similar to theirs, Cerb oil pressure gauge unreliable, or reassured because its always been that way over the eight months ownership and no sudden drop in pressure.
Also always had a poor reading on the fuel gauge which means it runs out of petrol when indicating 1/4 full. So okay I thought probably similar unreliable gauge, keep an eye on it and be reassured by its constant nature.
Recently I installed a lift into my garage, and for want of something better to do I looked for the oil pressure relief valve. Once located I removed the spring which was in good condition no sign of damage and difficult to compress between fingers.
I looked back at the car and for reasons I can't explain now decided against any evidence to replace it. I went and got one from Walldonway. To my horror when I matched up the springs the one from my car was about half a centimetre shorter than the new one. I tested them both on my home press and the new one was also considerably stronger.
I fitted the new one in the car and to my horror the idle psi went immediately to 80psi cold. I took the car on my normal 'go to work' journey for comparison. Not only did the engine noise die down in half the time it normally would, but even hot the gauge didn't go below 60psi and on hot idle 45-50psi. Thats another 20psi at the camshaft!!! Even my idle camshaft noise is noticeable less.
From this I think we should all review the advice to 'sit and watch'. I can't believe the spring isn't mentioned on any service shedule, although it is a known wear part for Cerbs, Walldonway weren't even surprised by my tale. I for one will be changing that spring yearly.
It cost me £4, and took me less than five minutes to do, and has probably saved me a considerable amount of future engine wear.
I would be happy to talk anyone through it, post piccies etc, or even point it out to you if you stray past brands hatch
DON'T WAIT.
Hi Julian,
I hope my email and recent posts helped a little. As you say spring is buck cheap and I will also ask Joolz to replace mine every service. I would also replace the main charging fuse annually as well if I were you, cos you know it will fail at midnight in the middle of nowhere.
Ceejay
I hope my email and recent posts helped a little. As you say spring is buck cheap and I will also ask Joolz to replace mine every service. I would also replace the main charging fuse annually as well if I were you, cos you know it will fail at midnight in the middle of nowhere.
Ceejay
Easy to do, simple undo the nut shown by the arrow, 24mm spanner. Inside you will find a small spring pushing on a small ball bearing. Remove, replace and do the nut back up, simple.
As far as I know Gazzab, this is much more important than a simple dial reading, it is actually the oil pressure.
From what I have read the oil pressure relief spring is just that, an emergency device which limits back pressure. The spring should only be forced back if the pressure of oil pumped by the engine is over a certain threshold dictated by the strength of the spring. If the spring weakens you get am increasing amount of oil allowed to bypass and a slow lowering of your oil pressure. If the spring breaks, a sudden drop. Its in a different place to the gauge oil pressure sensor altogether. If anyone knows different please email.
>> Edited by FourWheelDrift on Tuesday 27th July 09:52
This was a common fault on earlier cars, I think the guys who would take their cars to europe for sustained high speed driving would take a couple of springs with them as it was likely to break. I think TVR "uprated" the spring in 99, but I could be wrong.
DannyLT will know for sure.
Cheers
Whitey
DannyLT will know for sure.
Cheers
Whitey
Hi all,
apart from the significant increase in oil pressure the only thing I have noticed is that when the car is started from cold the oil pressure seems to build much more quickly than before. I've always hated the noise when the car is started up which occurs until the oil pressure builds, then its just tappety till warmed up properly. So hopefully this little spring will reduce cold start engine wear as well, all for 4 quid.
Graham, obviously mine was low when I first had the car but at hot idle now it's making 45, all your other readings seem similar. If in doubt get it checked.
apart from the significant increase in oil pressure the only thing I have noticed is that when the car is started from cold the oil pressure seems to build much more quickly than before. I've always hated the noise when the car is started up which occurs until the oil pressure builds, then its just tappety till warmed up properly. So hopefully this little spring will reduce cold start engine wear as well, all for 4 quid.
Graham, obviously mine was low when I first had the car but at hot idle now it's making 45, all your other readings seem similar. If in doubt get it checked.
. Will do my best. 
Good tip, i'll be doing mine this week.It is worth making sure that the WHOLE COMPLETE spring is removed. If a bit is left in, it can screw up the pressure and engine PDQ. Sometimes a broken spring can be responsible for the pressure drop. The other thing to check is that there are no residual oil leaks caused by the increased pressure. This will result in the oil level dropping quicker than normal which can cause problems.
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