Oil Pressure Problem?

[Size Nine Elm]

Question for the oracle on RV8 oil pressure... (Not sure if this should go on the Engines forum)

Pressure on startup/cold hits 45psi on the gauge on the dash. Once its a little warm, pressure sits probably about 35psi.

But if I sit in traffic, temp goes >90, then if I don't blip the throttle, the oil pressure seems to dip to the 15 mark on the gauge, or even lower. blipping the throttle raises it slightly, and getting moving brings it back up towards the 30 mark.

The <15psi worries me a bit - is this normal, or is something - oil pump? failing?

Fingers crossed...

[JonRB]

Can't help, I'm afraid. But I'd be interested to see the answer as I have something similar, although less extreme on the values.

[mean'n'roofless]

This is quite normal I understand. As the temp increases then the oil thins and unless you have to have some revs to throw the oil around the engine there is lower pressure.

This happens in mine too ad I have just had it back from service and a check over, everything perfect and still have the same dipping oil pressure. Some have pressures that drop lower than this.

Not a mechanic but have asked a 'techie' about this and been told it is fine

Just make sure there's oil in the engine and you're not using too much

>> Edited by mean'n'roofless on Tuesday 22 June 10:21

[K4TRV]

Couple of things - Gauges are notoriously inaccurate - plus the Oil pressue is not a linear scale/gauge. Unless you have very high mileage I wouldn't worry unduly. The engine is designed to move copious amounts of oil, but not at high pressure.

I've a pre-serp Chim and sounds just like yours - Just completed a Track Day, 7-sessions around Castle Coombe, used a full tank, fuel!!, by the 6th (average 8/9 mpg!!). Used no oil!!

Finally make sure you use 15/50 Mobil or 20/60 Millars. The 50/60 gives the oil its "bulk" which the V8 in pre/post serpentine comfiguration works best.

Trev McM

[prussianblue450]

Yeah, there's a school of thought that the recommended oil is really a bit too thin once it gets up to temp and you should use a thicker one.

I dunno mine tends to run at the same low pressure too

[ian187]

The presures sound exactly the same as mine! I understood as long as it doesn't go and stay below 10 psi, then its fine.

I run 0 / 40 Mobil 1 at the moment, but I was thinking of changing to a thicker oil 'cause mine does seem to burn it regularly and it would save me from some paranoia flicking between oil presure and temperature gauges constantly!!

[beano500]

Griff 500 - very similar behaviour. TADTS!!!

[JonRB]

I use Castrol GTX Magnatec (15W 40) as recommended by Dave Batty.

But let's not start the "which oil?" debate again - it can get ugly.

[JonRB]

ian187 said:

it would save me from some paranoia flicking between oil presure and temperature gauges constantly!!

Forgive my ignorance, but is this a multi-purpose gauge that you have had fitted aftermarket? I only have an oil pressure gauge in my Chimaera 500 and have always felt that it lacks an oil temperature gauge.

[beano500]

JonRB said:

But let's not start the "which oil?" debate again - it can get ugly.

"Which Ugly Oil" thread starting soon at a Pistonheads near you.......

If there's someone that knows what to expect with Rover V8s in a TVR it's DB. I've had the sender replaced once, connections can be dodgy too, but if either of those happens the gauge tends to bounce off the top of the scale. He reckons that mine is behaving as properly as you can expect. Otherwise, the reading is probably as reliable as a sundial in a hurricane....(my words not his!)

[RAW-SEWedge]

500 Griff with 49K miles and mine is the same. It has fresh mobil-1 15/50 in it.

[ropey]

JonRB said:

ian187 said: it would save me from some paranoia flicking between oil presure and temperature gauges constantly!! Forgive my ignorance, but is this a multi-purpose gauge that you have had fitted aftermarket? I only have an oil pressure gauge in my Chimaera 500 and have always felt that it lacks an oil temperature gauge.

JonRB - I believe he is referring to the water temp gauge and the oil pressure gauge.

In answer to the original post, that is what the oil pressure should do. This is detailed in The Bible too. Start - 35-45psi. Once warm, at revs - 30psi (ish), and at idle - 15psi (ish). If your figures are slightly different, then that may just be your gauge.

So long as the gauge always does the same thing, you're probably OK. So, if you're "when warm with revs" pressure is 30, and then one day it suddenly drops to 15 - then you should worry.

Kinda what mine is doing at the mo! Just got it back from David Batty, and I now notice my pressure gauge is all over the place - dropping down to 0 when cold, and when idling it keeps dropping below 15 until I blip the throttle.

Now where did I put David's number....?!

Ropey

[ian187]

JonRB said:

ian187 said: it would save me from some paranoia flicking between oil presure and temperature gauges constantly!! Forgive my ignorance, but is this a multi-purpose gauge that you have had fitted aftermarket? I only have an oil pressure gauge in my Chimaera 500 and have always felt that it lacks an oil temperature gauge.

Sorry, I wasn't very clear, I did mean water temperature gauge. I don't think I need any more gauges to watch, I'm paranoid enough at the moment

[JonRB]

ian187 said:

Sorry, I wasn't very clear, I did mean water temperature gauge. I don't think I need any more gauges to watch, I'm paranoid enough at the moment

Oh. Pity.
I was hoping that someone had come up with a neat way of adding an oil temperature gauge.

I've always thought the Chimaera's lack of an oil temperature gauge was a real oversight on TVR's part. I have oil temperature (but not pressure) on the Corrado and use it to determine when the engine is up to temperature and ok to open up a bit. I always feel that there is more guesswork involved when I'm driving the Chimaera.

[PeterC]

Mine is much the same with the added entertainment of registering zero on the pressure gauge for 15 to 20 seconds after starting up from cold having stood in the garage for a few days beforehand. After this the pressure stabilises around 60 and drops a little lower when warmed up.

The engine sounds fine, the dash oil pressure light extinguishes immediately and does not re-appear, but the oil pressure gauge will occaionally drop away to nothing then surge again up to normal level.

I suspect a faulty cpnnection or sender or somthing? Does anyone have any suggestions or is it a case of TADTS?

[k4trv]

PeterC said:

Mine is much the same with the added entertainment of registering zero on the pressure gauge for 15 to 20 seconds after starting up from cold having stood in the garage for a few days beforehand. After this the pressure stabilises around 60 and drops a little lower when warmed up. The engine sounds fine, the dash oil pressure light extinguishes immediately and does not re-appear, but the oil pressure gauge will occaionally drop away to nothing then surge again up to normal level. I suspect a faulty cpnnection or sender or somthing? Does anyone have any suggestions or is it a case of TADTS?

I'd try another sender - would presume more that the gauge is OK-ish, but senders are there on the block being fryed one minute, drenched with road spray the next and frozen days later.....:-)

Trev McM

[mean'n'roofless]

I dont think there should be any gauges except fuel. Let's face it, the more dials the more worries. In fact if I didn't have number plates to identify me I would be happy without a speedo as well.

[david beer]

With my Griff i turn on the ignition and the oil pressure rises to, minus 10! So if you add a resistor(10k) in my case, the guage now reads "Zero" .All it does is give you a starting point, the max it gets to is 55 and the lowest is 28-30 ish, where as it used to read as low as 20. I know i have not made any difference to the pressure, just makes me happy.

[victormeldrew]

JonRB said:

ian187 said: Sorry, I wasn't very clear, I did mean water temperature gauge. I don't think I need any more gauges to watch, I'm paranoid enough at the moment Oh. Pity. I was hoping that someone had come up with a neat way of adding an oil temperature gauge. I've always thought the Chimaera's lack of an oil temperature gauge was a real oversight on TVR's part. I have oil temperature (but not pressure) on the Corrado and use it to determine when the engine is up to temperature and ok to open up a bit. I always feel that there is more guesswork involved when I'm driving the Chimaera.

Jon, I have just fitted an oil temp gauge to my 500, alon with an ammeter. The latter is standard Griff item.

The oil temp gauge is in fact a water temp with an extra icon added. Caerbont will add a little oil can to a standard TVR water temp gauge. Costs though (£30 if I recall), but if you really want one it has to be done! Looks pukka.

I fitted mine while the dash was being reveneered - I cut the extra holes with a 52mm punch before sending the dash off to LCC for veneering. You need a new sump plug and water temp sender, and I have yet to get my sump plug drilled and tapped to take the sender, but otherwise the job is done. Most awkward bit is running the cable from dash to sump plug.

Credit due to Peter Beeches workshop notes for inspiration.

[Size Nine Elm]

Thanks for the replies, I thought it might be a TADTS, but was a little worried in case it was getting too low.

Currently using Mobil 1 (0/40) but have use Mobil 1 Motorsport (15/50) before - probably worth going back to.

Cheers,
Neil