Jump to content
SAU Community

Recommended Posts

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 by abr33

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)

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?

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 by blinksta

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?

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

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 :nyaanyaa:).

Failing that you can just not go WOT :teehee:

Edited by blinksta

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 by rockabilly

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.

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.

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?

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

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.

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.

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.

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?

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.

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

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
    • As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.    Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.   Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target. My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.  
    • It would be different if the sealant hadn't started to peel up with gaps in the glue about ~6cm and bigger in some areas. I would much prefer not having to do the work take them off the car . However, the filler the owner put in the roof rack mount cavities has shrunk and begun to crack on the rail delete panels. I cant trust that to hold off moisture ingress especially where I live. Not only that but I have faded paint on as well as on either side of these panels, so they would need to come off to give the roofline a proper respray. My goal is to get in there and put a healthy amount of epoxy instead of panel filler/bog and potentially skin with carbon fiber. I have 2 spare rolls from an old motorcycle fairing project from a few years back and I think it'd be a nice touch on a black stag.  I've seen some threads where people replace their roof rack delete with a welded in sheet metal part. But has anyone re-worked the roof rails themselves? It seems like there is a lot of volume there to add in some threads and maybe a keyway for a quick(er) release roof rack system. Not afraid to mill something out if I have to. It would be cool to have a cross bar only setup. That way I can keep the sleek roofline that would accept a couple bolts to gain back that extra utility  3D print some snazzy covers to hide the threaded section to be thorough and keep things covered when not using the rack. 
×
×
  • Create New...