Strange OPG

[David Lynch]

Hello Collective. Watch the MechanicalOil Pressure Gauge (rather than my poor lines)

 

Pressure drops off from >4bar to " class="smiley" /> Sudden return half way down the straight is bizarre.

 

Oil Level 'seems' good (checked last night, engine running and warm).

Apollo, Sump Gasket Shelf mod, No Sump Foam (though was fine when took it out after 6 years/25K miles)

 

My thoughts are:-

Pickup damage. Sump is intact but plenty of scrapes. can impact move it?

Some form of restriction in the Apollo drain

Drop oil and ensure close to 7½ litres goes back in

False reading down large braided hose

 

Ideas on a postcard ?...well here

 

I've even considered putting the foam back in 😳

 

Ta, David

[Graham King]

David, I'm pretty sure you will find this is due to being low on oil, just 1/2 litre low is enough to give the symptoms you describe. The pickup is at the front of the sump so heavy acceleration will force the oil to the back and away from the pick up.

 

I find that I can get different level readings at different times (I do remember reading a post on here about level readings when the system is pressurised and when it isn't giving different readings).

 

The pickup is bolted to the block so it would require a big impact to move it.

[myothercarsa2cv]

Looks to me like it's flapping in the breeze

 

My order of checks based on ease of doing them and assuming there are no leaks and oil level is fine (and I don't envy you this, as I had quite a few OP problems and it wasn't much fun ☹️):

 

Switch the gauge for a known working one and try to emulate the problem to check if the gauge is faulty, although you may not want to risk anything...

 

Check the PRV - big allen key required, make sure that the spring is still in one piece, the 'piston' isn't scored, and that it's the right way up. If this is faulty, it may cause erratic readings. Mine was installed upside down and so never shut and that gave me a max reading of 2 bar.

 

Swap the filter - you could have a duffer. Rare, but possible if you only started seeing this after a recent change.

 

Drop the sump and check the pickup is attached properly with o-ring seal in situ, and not block by anything - unlikely if you don't have the foam, as there's not much else to block it, but do it for peace of mind.

 

Check the Apollo tank for blockages - again unlikely, what's going to get through the pickup strainer and the plumbing to do it?

 

Then the hard part... Check the oil pump itself. You need to lock the cams, pop the belt off, knock the bottom pulley off the crank, etc etc... Nightmare, but Haynes will walk you through it. Not a lot to go wrong there, but QED did mention on their website that the standard pumps can start to disintegrate. Not to alarm you, I daresay this is pretty rare, but maybe a good time to uprate it 😬 (here)

 

If that still doesn't find the problem, the only solution is to send it to DVA and get an upgrade 😬

 

Edited by - myothercarsa2cv on 17 Apr 2013 14:40:18

[David Lynch]

Thanks Both, I'll start with another dip check as entirely possible level could be down by half a litre. I have never liked the Apollo dip reading methods though the while running approach is the one I use.

My interpretation of the drizzle on the dipstick was certainly not the top X (probably more mid). By my reckoning 1mm on dipstick is around 80ml so sure there's easily the margin you mention Graham. Then I'll go find some corners and perform some digital throttle applications

 

Simplest is normally the fix... I do simple well

[Graham King]

David, I always make sure mine is right up to the top, half way down the dipstick is enough to produce the symptoms, you describe, in my car. I have also fitted the Hellier Sump baffle and that did help but certainly doesn't eliminate the issue.

 

I think the only real answer is a dry sump but I haven't been able to justify the cost yet.

 

Graham.

[shn7]

I think the only real answer is a dry sump

 

The only way to be sure for track use IMHO.

[David Lynch]

Simply low oil level . Can't say I'm any the wiser regards the dipstick readings. I wonder if as level gets close to "correct" without a foam baffle there's a wave machine going on in there 😬