Under Pressure
Discussion
Oil pressure is very low at idle, it's a known issue with the Rover V8 but nothing to worry about. Mine goes to what looks like disastrous levels at idle (10 or less) but in reality it's fine. Check the levels regularly and look for the pressure whilst crusing. You should get 30-40 psi at 3,000 revs.
Dave
Dave
mine always stays around 45ish on the run-the constant volume type pump on serpentine engines means it should be stable throughout the rev range once above 2k "ish".on tickover when hot it gets as low as 20 or thereabouts from memory.this is always using mobil 1 15-50(never use 0-40).had a very bad experience with previous chimp running only 30ish on serpentine engine,using 0-40 oil.had to replace mains and big ends,and was lucky thats all it was!sorry for s.a. length reply but hope it helps.
donatien said: Oil pressure is very low at idle, it's a known issue with the Rover V8 but nothing to worry about. Mine goes to what looks like disastrous levels at idle (10 or less) but in reality it's fine. Check the levels regularly and look for the pressure whilst crusing. You should get 30-40 psi at 3,000 revs.
Dave
I am sorry but low pressure at idle is NOT a known issue and is definitely NOT something to ignore.
If the pressure is below 10 lbs then the chances are that the engine is on its last legs. or is about to die. TVR state that this is not normal and indicate a problem or knackered engine. Usually it is simple as a worn oil pump but it should not be ignored. Also bear in mind that the serp engines have a different design oil pump and run at higher oil pressures and 10 lb or below with them indicates a serious problem indeed.
BTw serp engines in good nick will often maintain a good oil pressure of 30-40 lbs irrespective of the revs especially if the oil is not really getting very warm.
Pages 37-41 in bible 2.
Steve
www.tvrbooks.co.uk
>BTw serp engines in good nick will often maintain a good oil >pressure of 30-40 lbs irrespective of the revs especially if the >oil is not really getting very warm.
Hmm, so what's the deal with the 5l engines then? They're pretty much universally regarded as running at a lower oil pressure than their 4l sisters. Is it a deliberate change? Is it a change in the pump, the bearing tolerances, or were TVR just not able to keep the pressure up after all that reworking?
Or are they all about to grind into grit? Should us 5L owners be concerned by 15psi idle and 30psi hot at revs?
Hmm, so what's the deal with the 5l engines then? They're pretty much universally regarded as running at a lower oil pressure than their 4l sisters. Is it a deliberate change? Is it a change in the pump, the bearing tolerances, or were TVR just not able to keep the pressure up after all that reworking?
Or are they all about to grind into grit? Should us 5L owners be concerned by 15psi idle and 30psi hot at revs?
I've not heard that comment before so not sure about universally.... Serp engine have a totally different oil pump which is far better and gives higher pressures compared to the pre-serp version.
BTW my Griff has 40-45 psi at revs and cold idle and about 30 at hot (90) idle and this is pretty normal/common.
>> Edited by shpub on Monday 10th March 15:11
BTW my Griff has 40-45 psi at revs and cold idle and about 30 at hot (90) idle and this is pretty normal/common.
>> Edited by shpub on Monday 10th March 15:11
www.pistonheads.com/gassing/topic.asp?action=bookmark&t=13849&h=0&f=8
for a start...
I'm not saying it's right, jsut that that's what I've always heard, and now I'm wondering whether it's not normal at all. And
whether I should look into it.
Having said that, it's always been that, and no servicer has ever
said there was a problem (they didn't shy away from prophesies of doom on any other subject!)
>> Edited by xain on Monday 10th March 16:22
for a start...
I'm not saying it's right, jsut that that's what I've always heard, and now I'm wondering whether it's not normal at all. And
whether I should look into it.
Having said that, it's always been that, and no servicer has ever
said there was a problem (they didn't shy away from prophesies of doom on any other subject!)
>> Edited by xain on Monday 10th March 16:22
Looked at it and seen nothing that says that 4 litre V8 engines have different oil pressure characteristics than 5 litre engines.
Are you getting confused with oil consumption which is by and large is greater on the 5 litre engines because the piston rings are different. Yes there is a difference here.
Steve
Are you getting confused with oil consumption which is by and large is greater on the 5 litre engines because the piston rings are different. Yes there is a difference here.
Steve
steve,
surely the pressure should not be constant!
warm at idle = 10-30
warm at 4000 = 40-60 (and highe)
a smooth rise on the guage holding a steady pressure at a steady rev,flattening out at about 4000 (when the o/p/r valve holds it )is more important...IMHO
least thats what i've been told! seems logical...
surely the pressure should not be constant!
warm at idle = 10-30
warm at 4000 = 40-60 (and highe)
a smooth rise on the guage holding a steady pressure at a steady rev,flattening out at about 4000 (when the o/p/r valve holds it )is more important...IMHO
least thats what i've been told! seems logical...
hate to butt in and sound like a scaremonger,but assuming your using mobil 1 15-50 oil,then 30psi hot when engine is up in the rev range is too low on a serp engine,constant or not.something is definately wrong,its not that difficult to drop sump and check bearings and it could save you an awfull lot of heartache!im glad i did on my old chimp, it was running 30psi hot as well.it was only after talking to ray at v8 developments that i learnt this pressure was too low(serp engine spec is different to non serp) and as i caught it in time i saved the need for a new/reground crank!
I didn't say it should be constant all the time , I said that it is not uncommon for the pressure to stay consistent, especially with the better oil pump on the serp engines and if the oil doesn't get really hot.
The oil pump pressure is controlled by a pressure relief valve and this will maintain a constant presuure of around 40 lb ish. So if everything is good then this valve will set the oil pressure and unless something happens in the engine to prevent the pump from providing this pressure, that is what you see. As the engine gets hot, the tolerances can drop, the oil thin and the pressure drop or the relief valve starts doing less work and the pressure is maintained. At some point it may drop below what the valve controls and you see a falling oil pressure.
If you use a thicker oil I use the Mobil 1 motorsport then the oil pressure will stay higher for longer and you may not see a drop until the engine is really hot.
>> Edited by shpub on Tuesday 11th March 08:11
The oil pump pressure is controlled by a pressure relief valve and this will maintain a constant presuure of around 40 lb ish. So if everything is good then this valve will set the oil pressure and unless something happens in the engine to prevent the pump from providing this pressure, that is what you see. As the engine gets hot, the tolerances can drop, the oil thin and the pressure drop or the relief valve starts doing less work and the pressure is maintained. At some point it may drop below what the valve controls and you see a falling oil pressure.
If you use a thicker oil I use the Mobil 1 motorsport then the oil pressure will stay higher for longer and you may not see a drop until the engine is really hot.
>> Edited by shpub on Tuesday 11th March 08:11
>assuming your using mobil 1 15-50 oil,then 30psi hot
>when engine is up in the rev range is too low on a serp engine
Hmm, well I'm using 0w40 Mobil 1 (as recommended!) and we've already established that there are plenty of sound 500 runners out there with 30 psi warm at revs pressure, plus it's been through 2 TVR dealers and Thames Valley Racetech without any hint of worry about the oil pressure. What makes you believe that 30 is too low?
>when engine is up in the rev range is too low on a serp engine
Hmm, well I'm using 0w40 Mobil 1 (as recommended!) and we've already established that there are plenty of sound 500 runners out there with 30 psi warm at revs pressure, plus it's been through 2 TVR dealers and Thames Valley Racetech without any hint of worry about the oil pressure. What makes you believe that 30 is too low?
what makes me think 30psi is too low using 15-50 when hot at higher revs? if youd read all ive written then youd know that a new set of mains and big ends is how i know!! my local garage did the work and i saw the bearings come off(down to the copper on some,but all were marked too badly to use)when new bearings went in then pressure was back to normal-45psi in same circumstances.my current griff also gives 45 in same circumstances and has only covered 10,000 mls.this tells me there in good nick and also gives a consistent picture of what to expect from a good engine.ray at v8 developments strongly advised using 15-50,my dealer,westover sportscars use 15-50(checked with them)and if you noticed ,shpub also uses the 15-50 grade(read motorsport mobil 1) im sure most dealers/specialists use 15-50.the engine was originally designed around thicker oils(being such an old basic design) and if you read your tvr car hand book it advises use of 5-50 mobil 1(no longer available)and also remember that a thicker oil will give much better protection when hot,and do these engines get hot?!! who advises 0-40? the choice is of course all yours.all imho of course
>> Edited by mongoose on Tuesday 11th March 09:33
>> Edited by mongoose on Tuesday 11th March 09:35
>> Edited by mongoose on Tuesday 11th March 09:33
>> Edited by mongoose on Tuesday 11th March 09:35
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