Oil pressure, where's it gone?
Discussion
Started it up earlier and low oil pressure light remained lit 
(my pressure gauge is currently out of action). Last time I used it was a good run last Sunday, parked it up with no problem.
Thought the switch looked a bit damp (not the most dry of garages), causing it to earth out. Bit of WD40 didn't do the trick. The switch is only a few months old.
A couple of starts the light did go out briefly before stating to flicker and then staying on. I began to suspect a blocked oil filter, which would explain why the car was fine on last weeks run, as the hot oil would be thiner passing easier through the choking filter. Also the moment after stating the car today the light did go out before coming back on, maybe the crap is dropping back down the filter pipe when switched off, restarting would force the rubbish back into the filter.......well that was the theory.
New oil filter courtesy of Halfords. The original did look pretty black inside, despite probably only covering 1500 miles in the car. Car restarted and light gone, sorted!................or so I thought. Five minutes of idling and guess what, the bloody light came back on! There does seem to be reasonable circulation, as the remote filter got nice and hot.
Left things to cool down and restarted. Light gone and left it ticking over for about 15 mins, no light. Switched off and was going to go out for a run, restarted 10 mins later and oil light back again
. Didn't go out for a drive in the end.
Now if left to idle at about 900 rpm the light flickers/stays on, if you lightly rev it to anything above idle the the light disappears (wouldn't do this before changing the filter).
This sounds to me now like a dodgy pressure relief valve. I just don't understand why this has suddenly happened after a week 'resting' in the garage. Engine sounds and runs fine.
Any thoughts?
Thanks.
James.
(my pressure gauge is currently out of action). Last time I used it was a good run last Sunday, parked it up with no problem. Thought the switch looked a bit damp (not the most dry of garages), causing it to earth out. Bit of WD40 didn't do the trick. The switch is only a few months old.
A couple of starts the light did go out briefly before stating to flicker and then staying on. I began to suspect a blocked oil filter, which would explain why the car was fine on last weeks run, as the hot oil would be thiner passing easier through the choking filter. Also the moment after stating the car today the light did go out before coming back on, maybe the crap is dropping back down the filter pipe when switched off, restarting would force the rubbish back into the filter.......well that was the theory.
New oil filter courtesy of Halfords. The original did look pretty black inside, despite probably only covering 1500 miles in the car. Car restarted and light gone, sorted!................or so I thought. Five minutes of idling and guess what, the bloody light came back on! There does seem to be reasonable circulation, as the remote filter got nice and hot.
Left things to cool down and restarted. Light gone and left it ticking over for about 15 mins, no light. Switched off and was going to go out for a run, restarted 10 mins later and oil light back again
. Didn't go out for a drive in the end. Now if left to idle at about 900 rpm the light flickers/stays on, if you lightly rev it to anything above idle the the light disappears (wouldn't do this before changing the filter).
This sounds to me now like a dodgy pressure relief valve. I just don't understand why this has suddenly happened after a week 'resting' in the garage. Engine sounds and runs fine.
Any thoughts?
Thanks.
James.
Think that you are fine, and I would personally only be worried if the light came on at more than 1200 revs. But better safe then sorry.
For your information: At low revs several RV8s are at the limit and can have flickering of the oil pressure light. If rev-ed and stays out it 'could' be ok. In my case it could be possible with a hot engine on a hot day: setting idle a bit higher (now 1000 revs) everything is ok and oil pressure on the working gauge is fine as well. As you mentioned the pressure relief valve is worth to have a look at (I did and replaced the original spring and all was back to normal.....)
Rob
For your information: At low revs several RV8s are at the limit and can have flickering of the oil pressure light. If rev-ed and stays out it 'could' be ok. In my case it could be possible with a hot engine on a hot day: setting idle a bit higher (now 1000 revs) everything is ok and oil pressure on the working gauge is fine as well. As you mentioned the pressure relief valve is worth to have a look at (I did and replaced the original spring and all was back to normal.....)
Rob
The obvious answer would be to replace/ repair the oil pressure gauge, that way you could rule out a switch fault. At the very least you need to hang an independant gauge on an oil gallery somewhere to prove whether you actually have pressure.
The RV8 was/is prone to a sticking relief valve, ISTR there's a modified 'tadpole' that self-centres more reliably than the standard piston.
Could be worth a valve strip, it doesn't take long but you might find you need arms like Inspector Gadget to get into it!
The RV8 was/is prone to a sticking relief valve, ISTR there's a modified 'tadpole' that self-centres more reliably than the standard piston.
Could be worth a valve strip, it doesn't take long but you might find you need arms like Inspector Gadget to get into it!
TVRleigh_BBWR said:
What oil you running. as it may be too thin and when hot and low idle, causing the light to come on.
15w40, super thick!The light came on straight on after a week of rest, so stone cold. Actually seemed to get a bit better as it warmed up, which may support the relief valve theory (hot-expanding).
Was going to try it again tonight, but got in a bit late and don't want to upset the neighbours.........again
.peaktorque said:
Thats Dave Ellis Race Engines - he does the tadpole valve talked about aswell - drop him an email or ring him he always replies.peaktorque said:
15w40, super thick!
I use Valvoline 15W/50. The RV8 was originally intended to be run on 50 weight oil and no amount of bull-pooing by TVR and/or their representatives is going to convince me otherwise. I had several instances of low oil pressure when using Mobil 1 10W/40, it's never happened with the Valvoline. On the rare occasions when I use the wedge in the winter, it's still not really cold enough to justify 10 weight.If I'm wrong and it somehow shags my engine, well then I'll just have to rebuild it. It's only an engine.
Phil Mycock said:
peaktorque said:
15w40, super thick!
I use Valvoline 15W/50. The RV8 was originally intended to be run on 50 weight oil and no amount of bull-pooing by TVR and/or their representatives is going to convince me otherwise. I had several instances of low oil pressure when using Mobil 1 10W/40, it's never happened with the Valvoline. On the rare occasions when I use the wedge in the winter, it's still not really cold enough to justify 10 weight.If I'm wrong and it somehow shags my engine, well then I'll just have to rebuild it. It's only an engine.
How did I manage that?
I'm not normally a lucky person!
I changed the relief valve today and it made no difference . Low oil pressure light illuminated below 1500 rpm.
Just about to remove the oil pump and sump to check the strainers, when I decided to just try the oil light sender from my 'spare engine' undercover in the garden (Pikey I know!).
Fitted the spare switch and now all is well!
. Low oil pressure light illuminated below 1500 rpm.Just about to remove the oil pump and sump to check the strainers, when I decided to just try the oil light sender from my 'spare engine' undercover in the garden (Pikey I know!).
Fitted the spare switch and now all is well!
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