Oil pressure drop 2kg @ full throttle

kokkolanpoika · Post by **kokkolanpoika** » Tue Jul 02, 2013 8:10 pm

Hi.

I have 5.2L RV8 with my SD1..
It has got some silly oil pressure problem. I have got RRC 1989 timing cover + oil pump witch inc JE tadpole + adjustable oil pressure spring.
I just change new oils 20w50 valvoline VR1 + new filter fram. + fit also new tadpole to make sure it is ok. It will slide ok.
And proplem still stays.
Proplem is when i will make approx 3/4 acceleration, oil pressure stays stable ~4kg up to +4500rpm.
But if i will make full throttle acceleration, when revs are approx 3800- 4000rpm, oil pressure will drop like stone to +2-2.5kg, and stay there if revs still rise. Then i will stop acceleration.. This will hapen 1st and 2nd gear, not all the time, but 90% depends how i will make acceleration. If i try 3rd gear acceleration, oil pressure is fine up to +4500-5000rpm..

I prime oil pump when engine is cold, no noises etc.. But if engine is hot, then i can hear that oil is flowing couple of second when i stop priming. Is this normal? Or is my oil pick up pipe gasket leaking? When i build this engine approx 5year go, no problem, those problems start last summer and winter make them worse i think.. I just take my car back to road, and notice this problem..
Idle pressure is ok..
Also could it be possible that G-forces is pushing oil away from pick up pipe? And then it will suck air? It has got STD SD1 sump, and "paffle" plate is bolted to block.

Engine is most powerfull condition in year 2012-2013.. Year 2011 it has got slightly less power, and car performance is also slightly worthless. I found slightly better adjustment in suspension.

Thanks if any one can help me..

Darkspeed · Post by **Darkspeed** » Tue Jul 02, 2013 8:42 pm

Sounds like you need a baffled sump and if not also get a proper windage / oil scraper for the crank - at those RPM's 2 litres can be misted up around the crank itself let alone the the litre stuck to the heads and valley.

kokkolanpoika · Post by **kokkolanpoika** » Tue Jul 02, 2013 9:03 pm

Thanks for advice..

Forget to say, i have got SD1 own pressure gauge and also fit temporary mechanigal gauge inside the car.. Both behave same way..

I also try Mobil 1 5w50 and same proplem..

cammmy · Post by **cammmy** » Wed Jul 03, 2013 9:54 am

You need some oil control bud, as soon as possible. I posted a link to a crank scraper recently, also look at sump baffle design.

http://www.crank-scrapers.com/Buick-Rover.html

It doesn't matter what oil you use as the problem is that your oil pump is sucking air/foam.

In the mean time, do not use full throttle! If it gets bad you will trash your bearings and possibly your crank.

kokkolanpoika · Post by **kokkolanpoika** » Wed Jul 03, 2013 2:31 pm

Just wonder is it safe slightly overfill oil sump, and make an test drive.. If i add approx 1l more, i think it will be ok if i only made an test drive.? And then i dry it away, depends how it will work.. I think this is the only way to make sure that i will need baffle, etc..

Post by **katanaman** » Wed Jul 03, 2013 4:01 pm

The guys are probably right with the oil control but a couple of other things to look at:

Did you get the pump base modified to take the tadpole? The original 90deg corner that the tadpole would sit in is useless for sealing properly most of the time . The pump base should be modified with a chamfer so that it has a larger seat to sit against.

I have seen more than a few fram filters not work properly, maybe try another brand. I always used original parts for the filters.

Ian Anderson · Post by **Ian Anderson** » Wed Jul 03, 2013 4:12 pm

My guess is you have too much oil in the sump.

You have a stroked crank so it goes lower into the sump

Each time it turns the big end hits the oil in the sump and adds air and splashes a whole lot up the inside of the sump making foamed oil

result you have too much air in the oil and the pump cannot generate the correct pressure a the air complesses and then dissapates

I am surprised at the amount you spend on your engines that you are not dry sumped

Ian

kokkolanpoika · Post by **kokkolanpoika** » Wed Jul 03, 2013 6:14 pm

katanaman wrote:The guys are probably right with the oil control but a couple of other things to look at:

Did you get the pump base modified to take the tadpole? The original 90deg corner that the tadpole would sit in is useless for sealing properly most of the time . The pump base should be modified with a chamfer so that it has a larger seat to sit against.

I have seen more than a few fram filters not work properly, maybe try another brand. I always used original parts for the filters.

I send my pump base to Je-engineering approx 7-year ago, and they do the job. It will seat properly, and it it slightly ported also..

I also try Bosch filter, same problem.
Before i switch back to 20w50 Valvoline, I slightly drain sump that oil level is on the bottom mark. Same problem. Now oil level is top mark, and problem stays, but look slightly better..

If filter/pick up pipe is resistive, in my mind oil presure will drop slowly, not like stone..
Fast dropping usually tell some inlet side air leak/cavitation etc..?

ged · Post by **ged** » Wed Jul 03, 2013 7:12 pm

Just to add another possibility. Have you checked the end float in the oil pump gears? Too much & you'll get cavitation & a sudden drop in oil pressure as the revs increase.

Regards Ged.

ChrisJC · Post by **ChrisJC** » Wed Jul 03, 2013 8:07 pm

I used a tadpole valve a few years ago.

I noticed that the oil pressure increased with engine revs, then dropped significantly when the valve opened. It didn't drop too far, maybe from 45psi to 30psi, then stayed around 30psi.

That was with 20/50W oil.

Chris.

teamidris · Post by **teamidris** » Sat Jul 06, 2013 8:00 am

Dry sump worked for me when I was worried about sucking air due to the oils position in the sump. I'm convinced it now starts better cold, better when hot, maintains a constant oil pressure through the rev range and cures baldness.
Okay, maybe not the last one, but I'm glad I spent cash and hours of work protecting my oil supply. If the standard set up was better I may not have bothered? But now I can drive it a lot harder and have more fun

kokkolanpoika · Post by **kokkolanpoika** » Wed Jul 10, 2013 9:05 am

i think i solve my problem.. I fill oil level approx 5mm over top mark, and made an test drive. Oil pressure stays above 3,5bar when acceleration almost all the time.. All depends is there a small hill or how tyres get traction.. Or how aggressive i pull 2nd gear. I think if i slightly more overfill the system, problem is 100% resolved..
If pressure start to drop in hard gear change, it will pump up usually right now..

So i will need good new sump..

SuperV8 · Post by **SuperV8** » Wed Jul 10, 2013 11:30 am

I would double check you have the correct dip stick & tube.
There are several different lengths, I brought a new OE dip stick and noticed it was (approx)25mm different to the old one, then after some research found out landrover have another dipstick for LEV (low emission vehicles) which is longer so obviously would lower the oil level.

Tom.

DEVONMAN · Post by **DEVONMAN** » Wed Jul 10, 2013 6:26 pm

As you are using a standard SD1 sump, the normal oil capacity is 5.5 litres. You should be able to check if you have the correct dipstick if you check the level with 5.5 litres in the engine.

kokkolanpoika · Post by **kokkolanpoika** » Wed Jul 10, 2013 7:46 pm

Yes i use STD SD1 sump.
I also use STD 4.6 efi dipstick/tube. I measure it and i also measure my original SD1 dipstick/tube, and make some calculations.. Both are same lenght..
And yes, my oil capacity is approx 5.5litre inc filter..

Car is performing quite well, I measure it to APEX and it will run 0-100km/h under 5s.. So i think fault must be in sump..

I just receive alloy flange witch i order some time go, now i can start to make home made custom oil sump..