RB25 new setup causing burning oil

[240sxrb25]

when this motor was all original not long ago it did not burn any oil and its apparent that something i did is wrong and causing an oiling problem.

i used to have a moroso catch can which was fed by both valve covers.

what i now notice is that oil is ending up on top of the motor through the breather vents on valve covers and through the breather.

i put a new PCV in and works.

i also have oil in my intercooler pipes. the turbo is nearly new and i dont think the front seal is bad.

all ov this leads me to believe i am getting crank case pressure still. please give me some pointers on what to do to vent the system or if you have any other suggestions.

im running an ems and afr's seem to be very good and im running about 18lbs of boost and just doesnt seem as fast as it should at 18lbs.(another symptom of posistive crank pressure.)

here is the setup
http://i33.photobucket.com/albums/d85/jasontucker/IMG_0094.jpg
you can even see that its spraying all the way to the intake mani. it was soo bad one day after mashing in 3rd to redline that it got oil on hte header and just went up in a smoke cloud and couldnt see anything behind me or in the car........

thank you

[Darius]

Have you done a leak-down test on the cylinders? It probably doesn't have anything to do with the catch-can setup unless it was not vented and promoted the pressurizing of the crank case and caused damage.

My guess is that the rings are toast on at least one piston.

[I LUV MY S13]

the only thing that can really lead to burning oil is a leak in valves or bad piston rings

[240sxrb25]

thats what im afraid of. from every other thread ive ready that is similar to my problem, the compression test normally gives away that there is a bad cylinder, or a few.

wierd thing is that if i remove the pcv valve, and remove the oil cap i get no air blowing out of valve covers which tells me there is minimal blow by at the rings.

thanks

[240sxrb25]

and doesnt bad valve seals normally end up making a puff of smoke on start up? mine never does

[Darius]

wierd thing is that if i remove the pcv valve, and remove the oil cap i get no air blowing out of valve covers which tells me there is minimal blow by at the rings.

thanks

If you removed the oil cap and PCV valve, no air would come out of the valve covers because it is finding an easier way out through the oil cap and pcv valve opening. I'm still sticking with my bad rings assessment.

[I LUV MY S13]

yeah ima go with bad piston rings..do a compression leakdown test

[rex2sx]

Lets understand something here..

A copmression test can tell you if you have good or bad COMPRESSION RINGS. If you do a dry and a wet test and the numbers come out the same, then you know you MAY have bad OIL rings, OR a leak somwhere causing more oilt o be in the cylinders

A leakdown test is NOT for oil. Its checking to see if the cylinder can hold compression NOT oil leaks.

What you need to do is log how/when the engine releases blue smoke. Things like valve guide test and oil consumptions test are really the only true test when it comes to oil leak diag and verfying that you have an oil leak. Mufflers and cats can make false exhuast colors, mainly making the smoke seem "white". Internal oil leak diag is not always easy. Many people just replace seals and oil rings and call it a day.

Though i will say it seems like, Darius, that idea might work. I cant fully discredit it but i ill try it sometime

[greenzenki86]

if it continues id tear it apart which I know you dont want to do....buuuuuut if something fails and the motor takes a shit.....youll be buying another rb you know?

[fliprayzin240sx]

i also have oil in my intercooler pipes. the turbo is nearly new and i dont think the front seal is bad.

http://i33.photobucket.com/albums/d85/jasontucker/IMG_0094.jpg


Looking at your setup and you said you have oil in the intercooler pipes. You have nothing hooked up into the intake where oil could possibly come from. Oil in your intercooler will only come from the turbo...

Unless that oil is residue from a while ago. Pull the compressor housing to make sure.

[Darius]

Lets understand something here..

A copmression test can tell you if you have good or bad COMPRESSION RINGS. If you do a dry and a wet test and the numbers come out the same, then you know you MAY have bad OIL rings, OR a leak somwhere causing more oilt o be in the cylinders

A leakdown test is NOT for oil. Its checking to see if the cylinder can hold compression NOT oil leaks.

What you need to do is log how/when the engine releases blue smoke. Things like valve guide test and oil consumptions test are really the only true test when it comes to oil leak diag and verfying that you have an oil leak. Mufflers and cats can make false exhuast colors, mainly making the smoke seem "white". Internal oil leak diag is not always easy. Many people just replace seals and oil rings and call it a day.

Though i will say it seems like, Darius, that idea might work. I cant fully discredit it but i ill try it sometime

Bad oil rings will not allow blow-by great enough in volume/force to blow oil out of a PCV system and all over the intake manifold. Besides, oil rings almost never fail before the main rings or ring lands. OP, do a compression test or leakdown test and they'll both tell you the same thing which is broken rings or ring lands.

Looking at your setup and you said you have oil in the intercooler pipes. You have nothing hooked up into the intake where oil could possibly come from. Oil in your intercooler will only come from the turbo...

Unless that oil is residue from a while ago. Pull the compressor housing to make sure.

I agree with you and it doesn't hurt to check this too, but that doesn't explain the oil splatter from the PCV system on the top of the intake manifold.

[eh?]

Say bye to your ring lands

[fliprayzin240sx]

Bad oil rings will not allow blow-by great enough in volume/force to blow oil out of a PCV system and all over the intake manifold. Besides, oil rings almost never fail before the main rings or ring lands. OP, do a compression test or leakdown test and they'll both tell you the same thing which is broken rings or ring lands.



I agree with you and it doesn't hurt to check this too, but that doesn't explain the oil splatter from the PCV system on the top of the intake manifold.

Hmm...didnt really noticed that. Only thing I can see is maybe a leak on the brake booster line, oil is getting pushed into the intake manifold and being forced up that line.

But thats alot of oil splatter to coming from that.

My bet is its coming from the breather. Almost all boosted engine will have some kind of blow by. Some worst than others. I'd run an oil catch can. I'd try to find a 3 line catch can. Cap the front where the breather line is at and connect the 2 lines up top into the catch can. The extra line on the catch can, I'd either run it back into the intake (so you can have vacuum in the head) or vent it. Some folks swear that running a vacuum source into the valve cover helps seal the rings up a bit.

[rex2sx]

Bad oil rings will not allow blow-by great enough in volume/force to blow oil out of a PCV system and all over the intake manifold. Besides, oil rings almost never fail before the main rings or ring lands. OP, do a compression test or leakdown test and they'll both tell you the same thing which is broken rings or ring lands..

The copmression in the cylinders would cause the blow -by. When you do a leakdown test theres 100psi limit. Cylinder pressures are much greater than that. Especially at the time of combustion. Id think youd hear it from the valve cover. We were referring to air not actually oil.

Oil rings can go before compression. I can show you threads of where compression numbers were good, yet oil was caked on the rings. Poor qaulity oil, lack of maintanance, and contaminated oil can chew up oil rings.

[Darius]

The copmression in the cylinders would cause the blow -by. When you do a leakdown test theres 100psi limit. Cylinder pressures are much greater than that. Especially at the time of combustion. Id think youd hear it from the valve cover. We were referring to air not actually oil.

Oil rings can go before compression. I can show you threads of where compression numbers were good, yet oil was caked on the rings. Poor qaulity oil, lack of maintanance, and contaminated oil can chew up oil rings.

I think you're missing my point. There would not be blow-by air like the kind needed to blow oil along with the air out of the PCV system if the compression rings were in good shape.

For the record, I know how an internal combustion engine works. :o

[I LUV MY S13]

Lets understand something here..

A copmression test can tell you if you have good or bad COMPRESSION RINGS. If you do a dry and a wet test and the numbers come out the same, then you know you MAY have bad OIL rings, OR a leak somwhere causing more oilt o be in the cylinders

A leakdown test is NOT for oil. Its checking to see if the cylinder can hold compression NOT oil leaks.

What you need to do is log how/when the engine releases blue smoke. Things like valve guide test and oil consumptions test are really the only true test when it comes to oil leak diag and verfying that you have an oil leak. Mufflers and cats can make false exhuast colors, mainly making the smoke seem "white". Internal oil leak diag is not always easy. Many people just replace seals and oil rings and call it a day.

Though i will say it seems like, Darius, that idea might work. I cant fully discredit it but i ill try it sometime

its to measure how much pressure is lost in the engine.

OP, when a cylinder has high percentage of leakage, first check the oil filler cap. Do you hear a hissing sound? If so, you may have pressure leaking by the rings. Is there air escaping out the exhaust? Is it escaping out the intake system? Then a burned valve may be the problem. If two adjoining cylinders have similar low readings and you hear leakage out the other cylinder, then a failed head gasket may be the problem.