Oil pressure

Oil pressure

Author
Discussion

SILICONEKID345HP

Original Poster:

14,997 posts

230 months

Tuesday 1st July 2014
quotequote all
Hello can anyone confirms what oil pressure a healthy engine should be ? The tester is on its way .its not looking good i have very low pressure on the gauge the the oil warning light is staying on confusedconfused


It could be the big end shells or oil pump !


Bloody upset .

Sardonicus

18,928 posts

220 months

Tuesday 1st July 2014
quotequote all
Or a wiring fault dont run it till you get an independent gauge on it 1st wink if its the bearings then there is a good chance your oil cooler fault as dumped oil previously (this being the case your arse needs kicking) no engine will tolerate oil pressure failure for long frown stay positive wink

ChimpOnGas

9,637 posts

178 months

Tuesday 1st July 2014
quotequote all
Let the external oil pressure gauge do the talking, the Bergen one I linked you to is at the very cheap end of the market but will at least tell you if you really do have an oil pressure issue.

As a bare minimum look for 15psi at idle rising to 38psi over 2,000rpm, at this point the oil pressure relief valve will start wasting excess pressure back into the sump.

These are the minimum figures I'd want to see, 25psi at idle & 50psi over 2k would be more indicative of healthy RV8 oil pressure.

The oil warning light starts to illuminate between 3-5psi, to be honest by then the damage has already been done, the sender & oil warning light system is normally pretty reliable but dont panic Mr Manering like Simon says the light can still come on if you have a back feed or partial short.

The oil pressure gauge should be completely ignored, the bellows type senders (no matter what one you have) are just too unreliable to be trusted.

Fit your external gauge and see what pressure you get at idle, get an able assistant to raise the revs to 2,000 then 2,500 then finally 3,000 but only if things were looking ok at idle.

Write down your figures and share.

If you're genuinely not making pressure at idle abort the test before further damage is done, it's likely your cam bearings have broken up or its spun a shell.

If you have a serpentine engine its not unknown for the oil pump to fracture, in this case the pump will still make pressure just not much.

Keep the faith and use your external gauge, until you do so you're just speculating as to the outcome.

Good luck with it mate, no one needs this but is is a lesson to us all regarding sandwich plates that I've always treated with some suspicion.

In my opinion only 2% of contributors on here really need an oil cooler anyway, the rest of us simply don't need them and would be in a far safer place leaving coolers to the regular track day guys.

phazed

21,844 posts

203 months

Tuesday 1st July 2014
quotequote all
Bloody hell Daz!

Short of checking it properly,the fact that the light is on, it doesn't sound good.

Don't run it until you have the gauge connected

Best of luck!

Hoofa

3,151 posts

207 months

Tuesday 1st July 2014
quotequote all
Daz just crank it with the gauge connected, don't start it !!!

See of there is any pressure on cranking

ChimpOnGas

9,637 posts

178 months

Tuesday 1st July 2014
quotequote all
Hoofa said:
Daz just crank it with the gauge connected, don't start it !!!

See of there is any pressure on cranking
Cranking the engine will give you the best part of fek-all oil pressure even on a healthy engine, just enough to knock the light out in fact but only if there's no fault with the light and as we know thats in question already.

I never understood all that tosh about the Tornado chip cranking more to build up pressure before you start, what you really want is a good prompt start so the engine is turning over above 500rpm as soon as possible.

Start the car, quickly check pressure at idle using the external gauge, turn off immediately if it can't make at least 10 - 15psi at 1000rpm.

I doubt even the healthiest engine makes much more than 7psi when cranking so it'll just scare the craap out of old Daz doing a cranking pressure test.

The poor boy needs reassurance... not another fright eek

SILICONEKID345HP

Original Poster:

14,997 posts

230 months

Tuesday 1st July 2014
quotequote all
Sardonicus said:
Or a wiring fault dont run it till you get an independent gauge on it 1st wink if its the bearings then there is a good chance your oil cooler fault as dumped oil previously (this being the case your arse needs kicking) no engine will tolerate oil pressure failure for long frown stay positive wink
I did not fit the oil filter !

Sardonicus

18,928 posts

220 months

Tuesday 1st July 2014
quotequote all
Yes but that little mishap should not of caused engine damage if it's like you explained, it wasn't running long enough.

jojackson4

3,026 posts

136 months

Tuesday 1st July 2014
quotequote all
My money is the relief spring stuck

Sardonicus

18,928 posts

220 months

Tuesday 1st July 2014
quotequote all
jojackson4 said:
My money is the relief spring stuck
Unlikely on the Serp front cover IMO and then you need to ask yourself what contaminant as caused the valve to stick open scratchchin unless the releif spring as broken scratchchin (possible) still its worth checking frown whats to lose? but Daz let someone else do this because in situ compressing the cap & seating the retainer/circlip will be a swine in situ and if I was this far I would be removing the sump and checking pump pick up security etc etc I would also knock the oil cooler out of the loop incase one of the cooler hoses have collapsed internally headache wouldn't be the 1st time ......

SILICONEKID345HP

Original Poster:

14,997 posts

230 months

Tuesday 1st July 2014
quotequote all
Sardonicus said:
nlikely on the Serp front cover IMO and then you need to ask yourself what contaminant as caused the valve to stick open scratchchin unless the releif spring as broken scratchchin (possible) still its worth checking frown whats to lose? but Daz let someone else do this because in situ compressing the cap & seating the retainer/circlip will be a swine in situ and if I was this far I would be removing the sump and checking pump pick up security etc etc I would also knock the oil cooler out of the loop incase one of the cooler hoses have collapsed internally headache wouldn't be the 1st time ......
I contacted Mocal regarding the problem with the oil filter catching the the nut which holds the stat in ,they said if the stat fails it is impossible to starve the engine with oil. If the stat fails it just goes round the engine .

The guy at Mocal seemed very concerned regarding the problem . The nut should not be anyway near the oil filter .

What is a the relief pin and what could be stuck ..?



Hoofa

3,151 posts

207 months

Tuesday 1st July 2014
quotequote all
Well I would not be starting it ! At least some pressure should tell you if the oil pressure switch should be working and go from there !

I have had a new sender go wrong and start to read silly low oil pressures when cranking and cornering ? But the oil pressure light was out.

jojackson4

3,026 posts

136 months

Tuesday 1st July 2014
quotequote all
Sardonicus said:
nlikely on the Serp front cover IMO and then you need to ask yourself what contaminant as caused the valve to stick open scratchchin unless the releif spring as broken scratchchin (possible) still its worth checking frown whats to lose? but Daz let someone else do this because in situ compressing the cap & seating the retainer/circlip will be a swine in situ and if I was this far I would be removing the sump and checking pump pick up security etc etc I would also knock the oil cooler out of the loop incase one of the cooler hoses have collapsed internally headache wouldn't be the 1st time ......
Yes it's a tt of a job to get back in

But it costs £0
For me it's got to be No1 on the list
No2 fk the oil cooler off and do the tests on the lump

jojackson4

3,026 posts

136 months

Tuesday 1st July 2014
quotequote all
Sardonicus said:
nlikely on the Serp front cover IMO and then you need to ask yourself what contaminant as caused the valve to stick open scratchchin unless the releif spring as broken scratchchin (possible) still its worth checking frown whats to lose? but Daz let someone else do this because in situ compressing the cap & seating the retainer/circlip will be a swine in situ and if I was this far I would be removing the sump and checking pump pick up security etc etc I would also knock the oil cooler out of the loop incase one of the cooler hoses have collapsed internally headache wouldn't be the 1st time ......
Yes it's a tt of a job to get back in

But it costs £0
For me it's got to be No1 on the list
No2 fk the oil cooler off and do the tests on the lump

jojackson4

3,026 posts

136 months

Tuesday 1st July 2014
quotequote all
What's the oil filter can that have collapsed?
Long shot

Pupp

12,206 posts

271 months

Tuesday 1st July 2014
quotequote all
Or maybe the oil filter that was not seating right because of the plate was simply refitted and the pressure relief valve in it has stuck open due to distortion of the filter body... again, worth eliminating

SILICONEKID345HP

Original Poster:

14,997 posts

230 months

Tuesday 1st July 2014
quotequote all
Why are Mocal telling me it`s impossible for anything to go wrong ,no matter what is happening with the stat .


Where is the pressure relief valve ?

Edited by SILICONEKID345HP on Tuesday 1st July 23:50

Hoofa

3,151 posts

207 months

Wednesday 2nd July 2014
quotequote all
What I want to know who fitted the oil filter ?....

Your problem is not the stat or fk all else except the seating of a oil filter that was ok before the oil change ?.. Come on daz your a plumber apply a bit of fault finding diagnosis !, I have the same mocal set up as you and don't have a problem, the oil filters do vary and I can only manage to fit one type due to the filter fouling on the cross members of the chassis. Other that that's it , unless who ever fitted the mocal plate didn't tighten up the oil pipe fitting enough onto the sandwich plate or didn't check the orientations of the -dash fittings.

Edited by Hoofa on Wednesday 2nd July 00:59


Edited by Hoofa on Wednesday 2nd July 01:01

s p a c e m a n

10,752 posts

147 months

Wednesday 2nd July 2014
quotequote all
SILICONEKID345HP said:
Where is the pressure relief valve ?
From the other thread on Saturday.. parts 5 6 7 and 8..

s p a c e m a n said:
Spring might be stuck on the oil pump pressure valve, try knocking the side of the pump with a hammer and if that fails take it out refit and try again?

Sardonicus

18,928 posts

220 months

Wednesday 2nd July 2014
quotequote all
try knocking the side of the pump with a hammer and if that fails take it out refit and try again?


[/quote] FFS dont tell Daz this eek he needs to get it to somewhere for inspection if he has money to spend on getting a later diff fitted he has .................... you get the picture wink