Excessive Oil Running From Cam Covers Into Can

[abr33]

Hi guys, last week i got my car tuned (finally) ended up running haltech e11 v2 and we got 260rwkw on only 14psi and 400nm torque. Could'nt go any more as auto started slipping and small intercooler seen the air temp to 70+ degrees. Still stoked as hell though it goes like a cut cat!

Now what i cant figure out is why i fill my (small) catch can so fast, it fills with clean oil that doesnt smell burnt at all and only seems to come from the passenger side cam cover breather, iv got the can plumbed back (sucking oil through system) i get no smoke that i can see at all out of exhaust.

My pcv? valve is clean and working too.

Im running an N1 pump and 0w-40 edge sport oil, done full build- rods, cp forgies, oversize bore, port n polish and heaps more.

Strange thing is on the dyno it didnt get a drop of oil in can, but driving on road it does (only when WOT)

My theory = oil filling cam cover faster than it can drain back helped by g-forces of acceleration therefore running into can when theres nowhere else for it to go.

Motor is 2500km old and runs smooth as.

I cant remember is there a drain in head at back of the passenger side cam cover? if not my idea might be correct?

I do run about 20mm overfull of oil to avoid getting any air up etc.

I think thats all i can tell you all

Sorry didnt add its an rb25det...

Edited February 19, 2011 by abr33

[DVS JEZ]

Search for oil control issues on rb. U will find exactly what ur after. Unfortunately u need to pull the head back off to fix it

[blinksta]

You have an N1 oil pump flowing to much oil into the head to which a stock RB has that problem from factory so all the oil is stuck in the head and none in the sump you might want to get it fixed asap as you will prob spin a bearing or something else.

As above you need oil restrictors put into the block to stop this from happening or a gravity fed oil return line from the back of the head into the sump (personally I have both and the N1 pump and no oil in catch can or the blow-by hose)

[abr33]

Cheers jez, found a few good threads!

How would it get on by tigging on a fitting to back of cam cover (exhaust side) and running a hose down to sump possibly in with the turbo oil return line? just how much oil needs to flow down?

[blinksta]

nah a fitting is tapped into the middle of the head and a hose is run down the intake side and plumbed into the sump

Like this:

http://www.spoolimpo...OilDrainKit.asp

(although this shows it going down the hot side which I would imagine that hose would simply fail)

Edited February 19, 2011 by blinksta

[abr33]

Looks alright, and yeah i imagine the hose would melt...

Recon before pulling head off its worth trying running return from the cam cover down?

Im only reving it to about 7500, most that have the issue iv now read about are revving them a fair bit harder than that?

[abr33]

Plus i see that running from rear of head is obviously lower, but providing you can get enough drainage, and not be filling catch can, and have enough oil in sump to not run out, your winning right?

And sorry about starting new thread on a known topic, i was searching with all the wrong words before

[blinksta]

I know the pain of having the head removed for something so simple, but these are the two main fixes (that I know of) to stop flowing to much oil in the head and none in the sump.

If the problem continues you could possibly have to re-build the engine again because no oil would be getting to the oil squirters (amoungst other things) underneath the piston which is then a domino effect.

End of the day as long as the sump has sufficient oil to continue operating under full load then everything is fine (famous last word ).

Failing that you can just not go WOT

Edited February 19, 2011 by blinksta

[rockabilly]

0-40w wont be helping you..too thin..

this is a 40year old engine design, it was made to run on 20/50w when new. least i would use is 10/40,, just my view..

Edited February 19, 2011 by rockabilly

[W0rp3D]

Is this a street car or a track/drift/drag car?

If its only a street car then your probably better of putting the standard oil pump back on, that should fix your problem.

[TiTAN]

nah a fitting is tapped into the middle of the head and a hose is run down the intake side and plumbed into the sump

Like this:

http://www.spoolimpo...OilDrainKit.asp

(although this shows it going down the hot side which I would imagine that hose would simply fail)

you do it to the exhaust side for a reason, the rotation of the crank aids drainage on that side.

[MBS206]

If you're trying to get excess oil from the head to the sump, you need a drain on the exhaust side from the head, down to the sump.

If you're trying to lower the crank pressure in respect to the head to also help drainage, you run one on the inlet side of the motor. It all has to do with the way the crank is spinning.

Do you still have the front oil drain on the passenger side connected, and not blocked?

[abr33]

I use it on the road, i may take it to track for fun but nothing serious. I do still have the front exh side drain and it works.

If i put a restrictor in with thin oil will it supply enough to the lifters?

Or if i was to put stock pump on, will it supply enough oil to everything?

SO, do i neave n1 on and restrict with drain back pipe, or put stock pump on with thicker oil?

And will the stock pump handle up to 8k revs and pushing 350kw? (thats my next tune goal)

OR, do i run thick oil and keep running the n1 pump?

Which is the best solution for street/very occasional drag use?

p.s. i do overfill the oil by near 2L because iv heard if this problem once before

thanks for the input

[Adriano]

Personally i think 2 litres overfilled is way too much, usually only gtr boys do it due to the extra g forces, and only by 1 litre, however it may have saved your engine. Im pretty sure to fit the rear oil drain you have to pull the head anyway, and to fit an oil pump, you have to pull the timing belt and sump. If it were me , i would use thicker oil only .5 litre overfill, and boot it once, check the catch can, if it is dry, then boot it twice and check again.

There is a lot of debate ver the head drains, but i cant see them making anything worse. I would be pulling the head if the oil doesnt fix it, and doing the restrictors and the drain if you are inclined.

[KiwiRS4T]

Used to happen to my RB25DET at only 7000 rev/min max. It is a known issue. I don't know why there are so many different answers. One theory is that pressure builds up in the sump preventing oil from returning. In any case restrictors to the supply and extra drainage seems to be necessary.

[W0rp3D]

Used to happen to my RB25DET at only 7000 rev/min max. It is a known issue. I don't know why there are so many different answers. One theory is that pressure builds up in the sump preventing oil from returning. In any case restrictors to the supply and extra drainage seems to be necessary.

so many different answers?

i only hear the one set of answers, the cause, from what i have read, has nothing to do with sump pressure, its purely because at WOT for extended periods of time will empty the sump into the head due to a lack of drainage back to the sump, obviously with that much oil in the head and a vent drawing air out from that area it is obvious that it will draw oil out with it.

2 litres is too much to over fill it, from what i have read for general street with a bit of "spirited" driving an extra 500ml and for track days an extra litre.

[abr33]

ok so running thicker oil should help alot, but say i rev it right out for a while say doing a top speed run, with thicker oil in it will it still eventually pump it all to the head or will extra .5 to 1L make it physically impossible to pump the sump dry?

Further to that, why did it not breath a drop on the dyno? or is the issue only present when g forces are in play?

[W0rp3D]

thicker oil might help it not be sucked out the vent tube as easy but since it is thicker and flows slower it would take longer to get back to the sump so it would make that problem worse, the only way to fix the problem is head off and do all the fixes, revving it less would also help or fitting a standard oil pump.

[abr33]

but being a thicker oil not as much would get pumped up to the head would it?

and by thicker oil, is 10/60 is thick enough or is it too thick?

[DVS JEZ]

If ur catch can is connected to the air intake of the turbo, try just having that line breathing to atmosphere so there is no vaccuum action sucking the oil from the head.

If the problem is still there try get some cam cover baffles. I think tomei make them. Helps stop the oil making its

Way out