Idle Oil Pressure

[griffdude]

Driving my 65k 4.3 quickly last night, pulled up at a junction & the big yellow oil light came on. The pressure is ok when there are a few revs, but at idle 8psi. Started it this morning 'just to see'& only showing 15-20psi cold idle instead of the usually seen 35ish psi.Again with a few revs pressure ok.The car has plenty of Mob1 in but is due 12k service in 1k. Also a couple of oil spots on o/s rear valence but nothing underneath. Any Ideas?

[jigs]

Worn Oil Pump?

[Trundle]

Have had similar problem on my 70K 4.3 Griff.Especially on track days and engine running very hot.At first thought it was a sticking pressure relief valve and so replaced the spring.

Tried thicker Mobil 1 Motorsport 15W which made a slight difference for a while but problem still came back.

Eventually sent it in to Team Proactive with instructions to find out why.

Turns out the 2 oil pump gears were badly worn and could not maintain any pressure on tickover.See Steve Heaths bible pages 43 and 44.
Further more they were loose and wearing into face of front cover plate causing a space that shouldn't be there and thus reducing oil pressure further.

Had new gear wheels and plate and problem solved but still not particularly high pressure although it is within Steve Heath's guidelines. Just over 25 psi when doing 3000 rpm and steady 18 on tickover, apparently it is volume of oil rather than pressure that keeps the V8 well lubricated.

Anyway, hope this is some help.
Trundle

[boosted ls1]

If this is a sudden change then something has probably broken like the relief valve spring. It may have jammed open. If it's been a gradual change then it could be wear in the engine. Or, your oil could be getting old and thin if you haven't changed it for a while. My rovers hated mobile 1 as was to thin. They liked a good 20/50 like amsoil or kendall. With turbo's after a thrash my guage would often only register a couple of psi pressure but the volume was still there and the engine was fine as evidenced by a leter strip down.

[griffdude]

yes it was a sudden drop in pressure so maybe it's the pressure spring after all? Regarding the oil, I've chucked in nearly 8lts in the last 5k so it shouldn't be in that bad condition??????

[griffdude]

where is the relief valve spring? If its part of the pump I might as well replace the whole thing & be done with it?

[boosted ls1]

Look at the timing cover, driver's side at the bottom. I'm assuming it's a Rv8 cover. At the bottom/side you will see a fat extension that houses the oil pump gears. There will be an oil pressure light switch there which is screwed into the housing. There will also be a fat nut, probably brass. It's been a long time since I last looked. If you undo the nut (19mm?)a spring should be released. It's a hard nut to access. Inside the bore at the top of the spring will be a miniture piston and this may have stuck in the bore. Pull it out and check it for wear. It can be replaced with a 'tadpole' version which has less bore to wall contact area. You won't lose loads of oil checking this over and it's quite easy to do but a bit fiddly.

[Trundle]

Griffdude

Did you sort out your idle oil pressure problem?

Was it the pressure relief valve springy thingy ?

After all the work putting new oil pump gears in mine,
I had exactly the same problem as you.Sudden drop in
pressure on tick over.Have had it before and cured by
unsticking the relief valve.This was before replacing the worn gears.

This time it happened after heavy bout of high revs.
Came upto the next halt sign.No oil pressure on tickover.Comes back at 1000/1100 rpm.

Trundle.

[david beer]

My last Griff suddenly lost most of its pressure, it was the oil pick up pipe in the sump. It had a crack in it and was sucking air as well as a little bit of oil. Its funny but the guy i took it to told me what it was before he looked at it.

[griffdude]

Had an oilchange to 20/50 which provided a short term fix.In fact stopped all dribbles.Did a trackday Sunday & after doz laps, pulled off for a rest & got 12 psi at idle.BUT the pressure recovered after 45mins rest, then same again.Ok on the drive home...Now gone to Dr Gulielmi's for some therapy & 12k service. Will let you know the outcome.

[calvinhutt]

Help urgently needed - long story as follows-

My 40K mile Griffith 500 was losing power, posted a number of messages about 4-6 weeks ago. Turned out to be failed hydraulic tappets and worn keyway on crankshaft (timing gears and chain were replaced at same time). £2000 bill with TVR main dealer put these right, picked the car up two weeks ago. It was pointed out to me upon collecting the car that the oil pressure light was flickering on at tickover, and the pressure gauge was also reading very low, and that at revs the pressure increased sufficiently to be safe (noted on the invoice). The pressure had been tested on a separate gauge to verify the pressure as being sufficient.

BUT,,,, within 40 miles, the oil pressure dropped to zero and the engine started making one hell of a clattering noise. Killed the engine and called the RAC. Rocker cover was bone-dry inside. The car is now back at the main dealer, they have said that the oil pump failed and this replacement is going to be £5-600, but their diagnosis is that the engine is old and worn out and that I am probably better off rebuilding the engine completely or replacing the engine.

Fine but:

1) until I took the car to them, the oil presser light / gauge were giving perfectly healthy readings

2) the pump base and gears were replaced one year ago

3) the car was last serviced at the same main dealer less than 4,000 miles ago - no indication was ever made that the engine was old and worn out at this time

4) I think I now have a fight on my hands to get my car returned to me in good working order.

To me, the whole thing smacks of either pressure release valve failure/ sticking or oil pump not being primed after putting the front cover was re-fitted to the engine. If it is the pressure valve, then tough luck I guess. If it is the failure to prime the pump, then I think we are talking negligence on behalf of the dealer.

I wish to get an independent TVR V8 Rover engine specialist in to take a look at the engine for me before I can decide what to do. Can anyone please help or suggest a course of action? I need to talk to a willing specialist in the Oxon / Bucks / Berks area who may be willing to help out.

Please help out! Desperate to get some fun out of this car this year!

Many thanks,

Calvin

[GreenV8S]

If they hadn't primed the pump, you wouldn't have had any pressure at all. I suppose it could be a sticking pressure relief valve or something silly like they bent/broke the oil pickup and it is pulling in air. The worn engine argument sounds a little hard to believe at that mileage and doesn't explain why the pressure has dropped suddenly at the exact time they did this work.

Given that you now probably do have a wrecked engine, I suggest you'll probably find it is more economical to buy a new replacement that get the old one rebuild, unless the old one is something special. The two big questions are what spec do you want and who is going to pay for it.

[boosted ls1]

If you intend to inspect the engine then I'd contact a mechanical engineer or the Tech dept of the AA or equivilent. These guys really are seen to be independent and have industry recognised qualifications etc. They also have access to amazing cameras and microscopic photography equipment. Anybody at a rover garage could provide you with a report etc but it would be open to challenge. You need a truly 'expert' report as it will be up to you to prove your case and to do that you need undisputible evidence. Without it you will be throwing good money after bad.

[david beer]

When my pressure dropped,as said above, my only damage was to the rocker assy as i believe these are at the end of the oil delivery. Mine sounded like it was going to be really bad so lets hope yours is like wise.I did mine myself so i think the total was 250, i think, it was 5yrs ago. For me it tought me that the guage is the one to watch as there was enough pressure so as the light didnt come on.It does make me think driving my Rangie that again, i would never know.