PCV sucking oil

[TurboBuRick]

I just put one of those aluminum vacuum blocks on and the pcv in now sucking oil. The only other thing I did was put a test pipe on. Thats it.

It sucks a crap load just sitting there at idle. smokes like a bitch.

I did run through past posts, I see the catch cans, other devices and the relocations.

My question (Does anyone have this problem who does not have a aluminum vacuum block?)

 

[87geeinn]

I had the problem pre-billet vacuum block. Perhaps you had a vacuum leak before and now the increased vacuum through the PCV is making the problem more noticeable?

 

[TurboBuRick]

Ya, I think your right. Just to confirm, I just got back from a ride with the pcv port blocked off. No smoke.

Too much vacuum is the problem.

What are you doing for a fix?


I think if we had some kind of regulator in line that only allowed say 15in of vacuum it might do the trick.

Catch can is kind of gaudy. No?

 

[mikec1969]

You would think with as much problems as the PCV causes in our cars more people would be willing to delete it. I blocked mine off, just to check a BL issue and the car runs better without it. I know you have to have breathers if you don't run the PCV, and my car has them installed, but my opinion is unless it's a daily driver you can block it off successfully. From a performance standpoint, why would you ever want to introduce oil contaminated air into the induction system? If someone insisted on running the PCV maybe create an evac system where the PCV hose connects to the test pipe. The exhaust pulse will create vacuum and evac the crankcase. We used that system on drag race cars for years, but ran a breather hose to the collector. Just a thought.

 

[TurboBuRick]

Mikec1969,
It's not a daily driver. I'm with you on the whole use of it all together, If it's going to suck oil.

87geeinn
I'm really wondering what good it's doing anyway.
The motor has absolutly no blowby.

Its surpassing it's pourpose and acting like a shop vac.
I guess the ring are good.

Down the road if the motor would develope some blowby, I would return it to do it's job. In the meantime it has no job. Runs better without the thing anyway.

 

[TurboBuickSix]

Mikec1969,
It's not a daily driver. I'm with you on the whole use of it all together, If it's going to suck oil.

87geeinn
I'm really wondering what good it's doing anyway.
The motor has absolutly no blowby.

Its surpassing it's pourpose and acting like a shop vac.
I guess the ring are good.

Down the road if the motor would develope some blowby, I would return it to do it's job. In the meantime it has no job. Runs better without the thing anyway.

If you think you have no blowby plug both breathers and go for a ride and boost it up to 15 psi.Don't get too nervous when you see the smoke,it's just from the quart of oil that shot out of your dipstick tube all over your DS header.Under boost we all have a good amount of blowby even if you see none at idle.I have been back and forth with the PCV oil issue and the very best solution is to use the factory breather behind the turbo with the pcv stuck in the outlet.It fit perfect after you remove the metal nipple.For the hell of it I pressure tested a GM PCV393 to over 50 psi and it holds no problem.The pass side VC has a nice baffle made to stop oil plus the breather itself has a filter inside to pull out some of the oil vapor and return it to the motor.I have a separator inline to see what is going on that holds about a half cup of oil and it has not even filled half way yet in about five hundred miles or so.Before I set it up like this it always smoked some at start up(sometimes bad) and the separator would fill in a FEW miles or even at idle.I have tried several methods of curing this including deleting the PCV and the above is by far the most effective.I wish I could claim this idea as my own but I can't,I was skeptical at first but am convinced now this is finally THE solution.Doing away with the PCV on a street driven vehicle is not a good idea.Do it for 500 miles then smell your oil,it will be smell like gas and look like crap.Another benefit of the PCV is the vacuum created against the piston rings,but with an open breather that is not realized as much.

 

[Ormand]

Has anyone figured out why the stock location PCV valve sucks oil? It would see like there is enough space underneath the thing that there wouldn't be any oil for it to suck. And at idle, almost all the oil should be down in the oil pan. At speed, maybe enough pumps up onto the lifter valley that there are little "pools" there, but the PCV valve is a couple inches above that. So how does the oil get to the PCV valve at idle- or any time, for that matter.

 

[TurboBuickSix]

I think there is just too much oil vapor under the intake and making the air twist and turn on the way to the front of that passenger side valve cover plus the filter in the breather "wrings"all the oil out by the time it finally makes it to the vacuum hose.Maybe why Chevy's don't have this problem because the way they are set up like that from the factory.I do remember those pcv valves that screwed on to the oil filler in the front of the intake on the 50's and 60's Chevs,maybe that's why they went to the valvecover design.Someone familiar with that era of cars might remember if they had the oil sucking problem.Buick could have thought they would get around it because of the intake vally pan being in the way? I am convinced it is the baffle,which is absent from the stock PCV system.If you would like to retain the stock location maybe a well designed baffle could be welded up on the bottom of the intake and then trim clearance from the valley pan for it.However,the stock passenger side valve cover seems to be an instant fix,try it and see.But you need the stock breather for that side and in good condition,including the rubber piece that used to go to the metal pipe.A zip tie on the vacuum fitting and around the PCV base where it sits in the rubber will be good insurance.

 

[TurboBuRick]

If you think you have no blowby plug both breathers and go for a ride and boost it up to 15 psi.Don't get too nervous when you see the smoke,it's just from the quart of oil that shot out of your dipstick tube all over your DS header.Under boost we all have a good amount of blowby even if you see none at idle.I have been back and forth with the PCV oil issue and the very best solution is to use the factory breather behind the turbo with the pcv stuck in the outlet.It fit perfect after you remove the metal nipple.For the hell of it I pressure tested a GM PCV393 to over 50 psi and it holds no problem.The pass side VC has a nice baffle made to stop oil plus the breather itself has a filter inside to pull out some of the oil vapor and return it to the motor.I have a separator inline to see what is going on that holds about a half cup of oil and it has not even filled half way yet in about five hundred miles or so.Before I set it up like this it always smoked some at start up(sometimes bad) and the separator would fill in a FEW miles or even at idle.I have tried several methods of curing this including deleting the PCV and the above is by far the most effective.I wish I could claim this idea as my own but I can't,I was skeptical at first but am convinced now this is finally THE solution.Doing away with the PCV on a street driven vehicle is not a good idea.Do it for 500 miles then smell your oil,it will be smell like gas and look like crap.Another benefit of the PCV is the vacuum created against the piston rings,but with an open breather that is not realized as much.

I'm sure I got blowby under boost but pcv does not do anything under boost. It actually can work opposite. Blowing preasure into the the crankcase. Unless you have a checkvalve inline.
I don't have factory valve cover any more so I would have to locate it in one of the breathers on top. Which I could do.


I am sceptical on the therory that the pcv will help rings seal and the oil stay clean.
Think about this. You have breathers in your valve covers and a pcv in the intake vally. There is no negative preasure created because of the breathers in the valve covers. Plug the valve cover breathers, then you got negative preasure in the crankcase which would pull on the rings.
With breathers in no way. your just sucking outside air in through the breathers.
Its like you said though. Plug the valve covers and look out. Something is going to blow once you come into boost.
But I tell you what, you just gave me a great idea.

 

[TurboDave]

Has anyone figured out why the stock location PCV valve sucks oil? It would see like there is enough space underneath the thing that there wouldn't be any oil for it to suck. And at idle, almost all the oil should be down in the oil pan. At speed, maybe enough pumps up onto the lifter valley that there are little "pools" there, but the PCV valve is a couple inches above that. So how does the oil get to the PCV valve at idle- or any time, for that matter.

Many times, it ends up being the wrong intake gaskets being used during an upgrade/rebuild. That valley pan becomes very important when left out.

 

[TurboBuRick]

Good Idea?

I have been pondering the idea of check valving the breathers in the valve cover so that they will let air out but not in.
Why has'nt any one tryed this. Seems logical to me.
I just worrie about too much negative preasure in the case messing with the oil flow. How much is too much?
Which leads me to something else that would need to be in conjunction. Some type of blow off or regulator that would only let negative preasure build to say 15in.
I know our cars ecm does not like any air that does not come through the maf. This would also help that problem.
I think this would cure the oil sucking also.

Lets put it this way. Take a golf ball in the palm of your hand then take your shop vac press the end of the hose against your hand over the ball.
Turn on the vac and see what happens. The ball does not move.
Pick the hose up and as soon as it moves enough air the ball gets sucked up.

 

[TurboBuRick]

Any thoughts?

 

[JDEstill]

Thoughts? Sure, bunches of 'em here
http://www.turbobuick.com/forums/showthread.php?t=73009

Take a look at the last 4 posts or so re: check valving the breathers.

John

 

[JSAautomotive]

PCV has been the nemisis of both the factory and the racing aftermarket.

GM had huge problems with it and windage with their LSx motors. Especially when you installed blowers onto them.

The Buick is no different from any other motor in that respect.

You're PCV valve must be located in an area where it does not see splashing oil period. It's not uncommon for a NASCAR engine to run up to 21 inches of vacuum on their crankcase systems, primarily because they are running low tension piston rings and need the ring seal that is provided by an efficient PCV blow-by scavenging system.

The PCV valve is also knows as an "anti-backfire valve". So it is a "check valve" if a backfire were to occur in the intake manifold. This keeps from igniting the fuel vapors in the crankcase and lifting your valve covers off the engine.

An excellent way to scavange the crankcase pressure caused by blow by of the rings is to vent the breathers after the MAF, but before the turbo inlet (similar to the way the factory did it) to suck the crankcase pressure out of the engine with the more boost you make (higher air velocity entering the turbo). Only problem with this is the "oiling" that happens throughout the intake air system (tubing, intercooler, etc). So then on alot of race systems, people will use some sort of vacuum pump on the crankcase pulling off of one valve cover and sealing the other with a "catch can" incorporated into the system.

 

[Blazer406]

.......An excellent way to scavange the crankcase pressure caused by blow by of the rings is to vent the breathers after the MAF, but before the turbo inlet (similar to the way the factory did it) to suck the crankcase pressure out of the engine with the more boost you make (higher air velocity entering the turbo). Only problem with this is the "oiling" that happens throughout the intake air system (tubing, intercooler, etc). So then on alot of race systems, people will use some sort of vacuum pump on the crankcase pulling off of one valve cover and sealing the other with a "catch can" incorporated into the system.

I know this is old.... but how would introducing fresh air post MAF but pre turbo inlet do anything but harm? You have unmetered air you are consuming that the ECM isn't figuring on to give you the proper air/fuel mixture.

 

[d0n_3d]

I have a stock PCV setup with a check valve before the PCV, stock valley pan setup, I have big breathers on both valve covers and I get quite a bit of oil blowing out of the breathers under heavy accel...they smoke just a tad at idle as well...any cure for this? someone told me to get some breathers with tubes sticking out the sides of them and route some rubber hose to under the car...

 

[stugots]

My up pipe to the throttle body pops off under boost 18-20 psi at times.Could this be because i dont have stock valve covers on anymore.Im still running PCV?

 

[oldprotrac]

This is getting me too.

I just blocked the PCV Valve off today, we will see if that helps. I would like to find a more permeneant fix though that looks good and instals clear.

That darn smoke at idle is really embarassing.

 

[usetaboost]

hmmmm

Could explain why I have smoke at startup, my driver's breather blows out, don't idle, etc, etc. Maybe I'll try pinching off the hose to the pcv valve once and see what happens. even if it fixes one problem, I'm happy

 

[GNVYUS 1]

Be prepared to change your oil very very often if you ditch the PCV. 1000 miles at most is what a bunch of PCVless drivers have mentioned.

I am going to try doing what the factory intended ( with a twist ) and run a catch can in between the valve covers and the inlet pipe. Let boost create the vacuum to suck the blowby out the covers and have the catch can take out the oil the factory neglected to do.