Hi All

If you remember about 4 months ago I discovered my orignal engine was knackered and I couldn't get oil pressure for love nor money...

I then had the joy of having to swap my lovely reconned 4.2 for an old 3.5 to get through the SVA test.

Well I ahve given in (a week after SVA) and put the 4.2 back in. But now I cannot get oil pressure in the new engine!!!!!!!!!

This time though I have a theory. I know the engine is good (as I was getting 40psi at tickover when cold before I took it out). I know the oil pump is good as it has been used on both good engines, but now no pressure.... Spinning the pump with a drill to prime the pump it spins freely, goes hard - oil pressure rises to 15psi and then starts dropping again back to 0psi with the drill going flat out. After a few attempts at this I was then getting no pressure at any time at all.

My theory is this. The V8 has a front cover that has the oil pump works off. Is it possible that front cover isn't sealing to the block properly and therefore allowing air to leak into the oilpump causing the drop in pressure? I did try tightening the front cover housing bolts and then it was possible to get about 17PSi (but I daresn't tighten any further).

Does that sound a possibility or am I clutching at straws? It is a new gasket but if that is a possibility then I try changing it or using gasket compound to help seal it.

Any help will be more than gratefully accepted as I am beginning to lose hope.

Mark

Could be several things, strainer too close to the bottom of the sump, poor seal between strainer pipe and bottom of block, pressure relief spring broken or too soft, worn pump gears?
Did you pack it full of vaseline before trying to prime?
Take your distributer out and use an electric drill to turn the pump.

If the engine has been siting around it is likely the oil has run out of the pump. The RV8 pump won't self prime so you have to get the cover off ans pack the space between the rotors with vaseline, put it back together and off it should go. If you are relying on the original electric oil pressure guage thenn these can also give rubbish readings, my rangie currently shows 20 PSI on idle and drops off the scale as soon as you rev it! This is after I just changed the sensor as the old one started leaking.

Best of luck!

~Caber

Its usually the oil pickup into the sump that's the issue with these engines giving the problem you describe.

Sump off, you have a little 'O' ring and a small bolt that holds strainer and tube in place, I suspect that this has come loose as you have managed to get pressure which has dropped away.

Alternatively I have seen poor landrover conversions is where the engine is placed too low and the front axle knocks the front cover up a tad, did you bash the front of the engine when removing, this could explain it so new gasket required.

If you do remove the front cover have an Ebay for a late 3.9 front cover, this has a different pump, do not get a 4.0/4.6 as these do not support distributors unless you want to 'megaspark' it and upgrade.

Also when the front is off its worth drilling a couple of holes from the valley forward so you lubricate the chain, have a google for this mod.

Regards Mark

Someone who had the same issue solved it by removing the dizzy,welded an extension to a scrap oil pump drive,clamped that to an electric drill and voila up came the oil pressure.

I ahve been running the oil pump drive (that the dizzy connects to) with an electric drill.

This pulls the pressure up briefly then it drops off again with the drill going full tilt. This is why I am suspecting an air leak.

Mark

can you put some gaffer tape round where you think the air leak is? it may hold the air out long enough to eliminate the problem. Or smear loads of silicon sealer over the join tonight and try again in the morning.

Hope it's not the guage...

Its possible the oil pressure relief valve has stuck open so you cant get a good pressure, or as you say, a gasket is not sealing fully.

paul

edit

if oil pressure goes up then falls off and does not return then the relief vale could be opening and then failing to close agian.

still just as likly to be an air leak.

[Edited on 7/7/07 by Paul (Notts)]

Right, so far today I ahve had the sump off, checked the oil pickup pipe (and installed new gasket on pickup and sump).

Had the oil pressure relief out (which is part of the new oil pump I had fitted to the new engine when I picked it up) and looks to be perfect.

Had the front cover off, and reattached. And still I ahve the same problem.

This is the same oil pump that was working perfectly on this engine before and the 3.5 for SVA but no joy now...

Next job, front cover off again and use gasket sealent all the way around in case it was a bad (new) gasket I put on?

(And typically the sun is out and it would ahve been a beautiful day for driving round in it...)

Mark

For those interested I have discovered the root of the oil pressure problem...

The timing cover (that houses the oil pump) has 2 oilways next to each other just above the oilpump, the block only has one. When I installed the new gasket i put it on the block and it fitted perfectly, but there was nothing to fill the void of that second oilway so it was just pulling air in there. A dash of that instant gasket stuff round the 2 oilway holes and e-voila - 40PSi pressure again.

Been out it her today and she is sweeeeet.

Mark

Sounds like they flogged you the gasket for a 4.0 /4.6 engine.... bummer !

nice one!!!

Hope the seal hold, would not wnt to lose pressure while driving hard. Is there any way to blank it off.