Thread: PCV Valve???

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Ok...so if y'all read my other thread I've been burning oil like there's no tomorrow...well listen to this.

I go to the Dairy Queen (Local classic hang out) with my friend following...so, he claims my pipes looked like diesel stacks when I took off, like thick, black smoke, smelled like oil, BAD. Just for a second under hard acceleration, that moment when there's a lot of vacuum...

So I check my oil when I'm there...down 3/5 of a quart...I also discover oil on the other side of my PCV valve...the side it's NOT supposed to be. So I have a few questions (by the way, my pcv valve is new...)

1). Is there any way to retain the PCV system without burning oil (right now I have baffles in my VCs, no screen or anything.

2). Would it be bad just to run two breathers?

3). Has anyone ever heard of a PCV burning oil like that?

Where is your PVC located. and is there a baffle under it? If oil is spraying directly on the PVC valve it will be sucked into the intake and burned.

If the it's not oil from an unbaffeled PVC valve, it could be worn out rings. An easy way to tell is with the engine running pull off the oil fill capn and pull and plug the PVC valve. Rev it to a high idle, if you have a bunch of oil smoke coming out of the oil fill the rings are shot.

I have pretty much the same problem. I deleted my PCV and ran two breathers. The only problem is the smell of engine gasses, they are pretty awful. Plus it's just masking the real problem. I have seen many BB engines with huffers on them that run one breather and a PCV valve with 0 problems, so I know the rings are toast. Gonna tear it down this winter and make it right. If the rings are truely shot, you probably have pretty good blowby as I do. My breather on the right side of the motor spits oil out, and the VC has a baffle that I even put PCV filter media in. I am now noticing since I put the PCV back in, I am starting to push oil out the intake. This problem has no easy fix. Hope this helps.

Keith

If you are getting blowby those fumes are going to be sucked up by your PCV system. It is essentially an open hose running to vacuum, nothing to keep stray oil or oil fumes from being vacuumed out of the crankcase. The check valve portion of the PCV is only to keep backfires from igniting an explosion in the crankcase.

I'm running two Moon breathers on my 27, one on either valve cover and I get no fumes, no oil spots, etc. We just had this discussion on another forum and people were saying you HAVE to have a pcv system to eliminate moisture and fumes. But I think if the engine is tight and runs at 180 it will be fine with breathers only.

With the amount of oil burning you are describing you have some sealing problems somewhere......rings, guides, etc. From our own past experience I can tell you it can be all the above and will really suck up some oil.

Don

Time for a leakdown test on the old 390, I'd say! If I recall, you recently did the heads...this will also serve to put a bit more pressure on the rings. If the rings are worn and/or cylinders egged from years of pistons going up and down in them it's gonna puff some oil.

I put a breather on it last night at the DQ before I drove home...all the way home, no smell (other than the iniial oil i spilled on the exhaust, and no oil out the breathers. This morning I checked, and no oil missing, so none burnt on the way home last night...the engine's about 7 years old, and didn't smoke before or after the refresh thing...but I have a feeling he new rockers are aiding in oil finding it's way up the baffle...I went out and bought a new PCV today, one of those Spectre ones that looks like a breather, but it's essentially a PCV in a hollow case with a barb...I'm hoping it'll act like a catch can and re-condense the oil n let it drip back down...

There's no screen in the baffle, would this be a problem? I'm thinking about stuffing one up there for good measure. I'm really thinking it was the PCV, considering the way it happened under hard vacuum just momentarily, and stopped when I put that other breather. I don't want to run two breathers, I think it'll just cause more problems...any input on that?

Is the PCV valve on the front or rear of the valve cover??? It should be on the front, but I've seen (and done) the old brain fade thing and put the wrong valve cover on the wrong side and have the PCV valve at the rear of the engine, then under hard acceleration all the oil goes to the rear of the head and the drain backs aren't adequate to get it out of the covers, so it gets forced out the breather/PCV and around those silly grommets that never do seem to seal tightly!!!!

Oh wow I didn't even consider that...it's on the passenger back side, breather's on the drivers front....I'm guessing i should swap them then?

I got the car the way it is...well, as far as PCV location, but before I went through it she wouldn't pick up like she does now, and it's only recently I've been getting on it...so I'm gonna try that too...to do this I'd have to swap covers though, as in one side to the other...I'm running Power by Ford ones, so there's actually a difference in the cap and PCV holes in general...

Originally Posted by Merc 006

Oh wow I didn't even consider that...it's on the passenger back side, breather's on the drivers front....I'm guessing i should swap them then?

I got the car the way it is...well, as far as PCV location, but before I went through it she wouldn't pick up like she does now, and it's only recently I've been getting on it...so I'm gonna try that too...to do this I'd have to swap covers though, as in one side to the other...I'm running Power by Ford ones, so there's actually a difference in the cap and PCV holes in general...

Won't do you any good - my fabricated covers are the same way, ports on the left as you face the covers, so they interchange from side to side but your ports will always be driver's front, passenger rear. I'd say you've got ring problems, or a severe baffle problem letting oil get up to your PCV. My money's on worn out rings, but I hope you find something else.

Well I got the Spectre PCV thing on and started her up, no smoke! Other than the puff of it on the first fire, no more black, anything...I have yet to accelerate down the road, it's kinda late, but it looks like the new PCV thing did it...