Here I go again....PCV

O

opzWE4

New Member
Joined
Jan 11, 2002
Just when I think I may have the problem solved, it's here again. Still sucking oil from the pcv. Where in the hell can so much oil come from?:confused: I pulled the intake, reworked the valley pan so no oil from the return line could get on top, or so I thought. I can't see how else so much oil can get ontop of the valley pan, I mean isn't that what it's there for? To keep the oil splash down? I'm running a seperator right now, but really didn't want to have too. After I got done with the intake, I didn't use the seperator and drove it for a little while without it. Now, I pulled the up pipe and looked in the plenum, and it's soaked with oil again, starting just behind the throttle blade. Pulled the vaccum block and it has oil all in it, and around it. So, I guess I'll have to keep using the seperator, and draining it every 30 miles:mad:

It seems that it draws more oil from the pcv after driving and then letting it sit at idle. That's when it really starts sucking oil. Could this mean anything? Could a wrong PCV cause this? I've got a new one, but it's not a delco, can't seem to find one anywhere. This is just CRAZY!
 
I have the same problem. I have the right AC PCV valve, reworked the intake pan, used the Fram G3 filter, nothing helped. My engine has less than 3,000 miles on it and above adv. vacuum. I think the vacuum being pulled is causing my problem. I blocked the PCV off and this problem stoped. As you know and have read it is not a good delete the PCV valve. I am still looking for a good oil seperator to use. I don't drive this car alot so I have been slow to come up with a good oil seperator.

The last two motors that I have rebuilt have this same oiling problem.
 
Well, let's all keep this thread rolling until this mystery (with a fixable explanation) is resolved, for all of us.

:)
 
I'm not sure what to do, I've tried everything. Like you, when I block off the pcv the problem goes away. I wish I could relocate the pcv somewhere else, where it has a less chance of getting near the oil, but I don't know where. I've even been pondering taking a valve cover off and making a hole, and adding a gromet, then putting the pcv there, like a SBC has. I don't know if that would work though. There has to be a fix for this, but no one has been able to tell me about it so far. This has been a 6 month ordeal so far. I too, think it's the vaccum, but damn. Has to be a solution. I wonder why some cars have this problem, and others don't seem to?
 
What I did was got a fitting to screw into the valley side of the block for the turboboil return. I welded a tube inside that fitting and cut the tube at an angle facing down to direct the oil away from the valley pan, then opened up the oil return slits in the valley pan to make sure they would return as much oil as possible. All this was done on my buddies car as mine is almost back togeather :D , and it worked on his car.

Hope this helps some, Jeromy
 
Thanks, Clean 86!

With that kind of help/sharing, we can get to the bottom of any problem, and find a cure.

Thanks to all who take the time to help.

:)
 
I don't really look forward to pulling the intake again:( Maybe that's the only way to fix it.
 
I have the turbo oil return shelded so it does not get onto the valley pan. It did not change my oiling problem.
 
Chris, did you open up the slot in the rear of the valley pan gasket that returns oil to the pan? It is to small in my opinion so I opened it up with a screwdriver so oil can run through it much easier.Oil will get up there if we can get it to drain quickly there will be no oil for the pcv to suck up.
 
Yes I opened it up. I do this on all of the valley pans I install because the slot is almost closed to began with.
 
Not meaning to bark up a different tree...

You said you put a new PCV in and it was not an AC Delco... I remmeber a long time back talking to a friend of mine that work at a GM dealer. He was saying that even the AC Delcos were not always working properly from the box. He said he would have to check three or four before he could get the right one.

You're talking about taking intakes off and stuff... just wonder if you're prob lies there... I think I have a similar prob that I want to investigate when I get back.
 
I've got a new Delco pcv coming, so I'll see if that makes any difference. That'll be the third new one, although the first replacement delco. I don't think it'll solve the problem, but you never know without trying. :)
 
Why is it a problem to block off the PCV when the engine can breath out the breathers on both valve covers?

Also why do these engines seem to fling so much oil up on the bottom of the intake?
 
Not that it would fix it completely, but may help to mitigate the problem some...

The flow through the PCV valve depends on the crankcase pressure and the intake manifold pressure. If you pull 18" of vacuum in the intake, and have atmospheric pressure in the crankcase, then you get a higher flow through the PCV than if you pulled 15" of manifold vacuum and had 5" of vacuum in the crankcase.

I'm thinking that the highest PCV flow makes for the greatest amount of oil sucked up. And the higher the manifold vacuum, the worse the problem.

Two ways to mitigate this that come to mind:
One, if the crankcase was sealed. Take the breathers off the valve covers, and let the PCV actually pull a vacuum on the crankcase. That would reduce the flow. Of course, once you get it on it, where would any excess crankcase pressure go? I'm thinking you start blowing oil pan gaskets and the dipstick tries to shoot out the hood. Really, check valve type breathers would be perfect. Don't let fresh air in, but let any positive crankcase pressure out. A setup like this would also get contaminants out of the oil better, actually pulling a vacuum on the crackcase would get water/gasoline/etc to boil out of the oil much faster and more completely. I bet it would also reduce complaints of oil leaks from the valve covers, oil pan, main seals, etc...

I wonder if having the stock setup, with just one breather instead of two, has any effect on this.

Two, add a restriction to the PCV line. A valve or a jet in the line would cut the flow through the PCV and presumably the amount of oil sucked in. Not as theoretically good as option 1, but a lot simpler.

The other ideas I've seen have been focused on trapping the oil that gets sucked up (ie filters and catch cans) and reducing the amount of oil that gets sucked up no matter what the flow rate is through the PCV (ie baffles and valley pan modifications). Maybe it takes a combination of all of the above...

Thought about both of these, but haven't tried them yet. If someone does, let me know how it works!

John
 
I think Walt Judy (hoping I'm giving credit where it's due) posted the idea of putting the PCV in the stock passenger side breather thingamabob (the one that used to connect to the turbo). You just cut the nipple end of the PCV and it fits pretty snuggly in that thing. Then you just run a rubber hose to the vacuum block like usual and plug the stock PCV hole in the intake. This way you use the baffle that's in the PS valve cover at the breather hole to help prevent the oil suck problem. I've been hesitant to try this since I'm not sure how the PCV would function way up there in the front of the motor as opposed to the stock location on the intake manifold. But it could be worth a try. Don't know if Walt Judy runs this setup but I think he's one of those guys with a 10 sec TSM car so he probably knows what he's talking about.

I remember reading this in an old PCV post.
 
I didn't see walt's post, but that's what I did. Haven't had any problems except keeping the PCV in there at high boost. I tie wrapped it and hit 25 pounds and so far, so good.

HTH,
Paul
 
So then what do you use to plug the PCV hole in the manifold base?

I am concerned that when I used the Fel Pro 1200 intake gaskets with no valley this PCV thing is going to become an issue
 
As a possible solution, what about putting a small fuel filter in-line with the PCV, one of those small clear ones??? it may provide enough impedance to the oil flow so that the PCV will still work while stopping the oil??? never did it, just a thought.
 
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