Crank case pressure problem under boost. Oil smells like gas

[Turboeagletalon]

History:
OK i replaced my PCV valve
Did comression test: 155, 155, 155, 155 8.5 compression ross pistons.
This is a foal built motor.
6 bolt swop in 2g gsx

I am getting excesive crank case pressure that caused the oil pan to leak.

Under boost you can smell burning oil.

im running 10 lbs till she boost creaps to 19lbs at 4800 rpms and holds it till red line

My oil smells like gas i asume im getting some blow by at my rings. But i am also wondering if maybe it's valve seal.

I have tryed useing a check valve, and T-ing of my breather and my PCV valve without any result. And yes i did use a catch can.

Any ideas on ways I can correct the situation.

 

[fourreGsixty3]

How long since you changed your oil? If its smelling like gas you will want to change it soon, because the viscosity is/will be changing due to the gas. Compression might be good, but to a leak down test... between 10%-30% leakage is good, any more then that, and your ring's, cylinder wall wear, or hole in the piston are the problem. If your ring's turn out to be bad then that is your problem why you are getting gas in your oil.

ALso this is assuming that the PCV system is hooked up correctly.

 

[turborebel]

A wet compression test will show you if it's the head or the rings. How many miles are on the rebuild? Make shure your catch can has a big enough hole on top to let all of the pressure out.

 

[Turboeagletalon]

yes the pcv valve is hooked up corectly. Ok the motor only has 1000 miles on it. it has great oil pres
ross8.5 pistons, eagle h beam rods. balance shafts removed. had the entire rotating asemply re-balance, rods rebalanced, the pistons came already weight matched.;
cometic head gasket, arp head studs, torqued to 110 lbs
motors solid.


she pulls so danm hard

 

[Turboeagletalon]

A wet compression test will show you if it's the head or the rings. How many miles are on the rebuild? Make shure your catch can has a big enough hole on top to let all of the pressure out.

so what i should drilla hole in the top of my catch can. ... that dopesn't make sence. i did the thing where you use a fuel filter inline for the breather. and then i just replaced it with the cathc can

 

[Turboeagletalon]

i don't think the rings are at all the problem. ... i have perfect compression. perfect i tell you.

 

[turborebel]

The crankcase pressure needs to go somewhere. My catchcan is from Summit Racing and it had only one 1/8inch hole on top. After drilling three 3/16 inch holes in the top, it worked much better. As far as your compression, the wet test is the easy way to see if your rings are perfectly seated. I would like to see the results.

 

[Turboeagletalon]

see let me break this down.
in vac- the pcv valve is pulling pressure from the crank case, and under boost the breather is venting the pressure from the crank case.

correct???

 

[turborebel]

Yes, I agree.

 

[Indyxc]

see let me break this down.
in vac- the pcv valve is pulling pressure from the crank case, and under boost the breather is venting the pressure from the crank case.

correct???

Yeah exactly, but there isn't as much crank pressure under vacuum than boost, so it's kinda of pointless.

I'd consider removing the PCV and running 2 lines to the catch can, and see how that does. If it's still a problem consider making larger vent lines, or adding a 3rd source to the catch can and hooking that up to a vacuum source under boost such as the exhaust or intake pipe.

So there are 2 lines hooked up to the valve cover to the catch can, and one running from the catch can to a vacuum source to create a larger pressure differential between crank case and catch can.

 

[romeen]

see let me break this down.
in vac- the pcv valve is pulling pressure from the crank case, and under boost the breather is venting the pressure from the crank case.

correct???

Yes, under vacuum the crankcase is being ventilated through the PCV valve into the intake manifold. But the removed gas must be replaced with fresh air and this comes from the connection to the intake pipe. This is metered air. If you run an open filter or open catch can (unsealed) you will be allowing unmetered air into the engine.

Under boost the crankcase doesn't just passively vent, it is actively sucked out by the high velocity incoming air in the intake pipe. This is why the stock configuration is better.

This topic has been discussed in detail. Here are some threads that may help.

http://www.dsmtuners.com/forums/showthread.php?t=229338

http://www.dsmtuners.com/forums/showthread.php?t=254437 (note post #14 in this link regarding oil smelling like fuel)

 

[Turboeagletalon]

ok i have my set up know so that my brand new pcv valve is running strait into my intaker and me breather is running threw a catch can and into the intake pipe.

so fare i have had good results. i have a small oil pan leak now due to the past damage but it only really only flairs up under high boost. A little oil loose i can deal with. I get paid tomaro. So I am going to change my oil and replace the oil pan seal. and the turbo oil return seal.

I wish there a way to make a breather on the lower side of the motor. in the actual crank case. That way the pressure isn't fighting the returning oil from the head.

 

[turborebel]

Don't forget the crush washers for the two 10mm bolts on the oil pan turbo oil return line.

 

[Turboeagletalon]

i pretty mutch use those on everything. but thanks for the reminder

 

[Turboeagletalon]

you'll be happy to know that the problem has pritty mutch cleared up. im going to do an oil change on her today and hope for the best. im allso going to put ina aone way water/air chech valve before my pcv valve that way it has a little added help