PCV Questions

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PolarBear

PolarBear

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I guess this will prove that I know just enough to be dangerous..........

About a year ago, I put Edelbrock valve covers on my stock 1965 273 V8. The old PCV didn't work on the new covers, so I bought a new one that did. The old oil breather cap didn't work either, but I didn't buy a new one. Instead (like an idiot), I bought a plain old oil fill cap (no breather).

I'm not really sure how many miles I've driven the car since changing the valve covers, but it's gotta be betweeen 500 to 1000. On the way home recently, the oil light came on, and I could see a little bit of white smoke in the rear view mirror. When I got home (about 5 minutes later), quite a bit of the rear end of the old 'cuda was oily........ I was pretty upset, and not thinking real clearly..... but I seem to remember that there was oil dripping from each tailpipe.

I told a mechanic buddy my sad story..... that the engine (which only has about 6000 miles on it since being rebuilt) wasn't running poorly during the incident, and that I coudn't believe anything inside of it (like a ring - or valve seat) would have broken.

He said if the oil was truly coming through BOTH tailpipes, it might be something simple - like a bad PCV.

Well, here's where I am now. I bought a new PCV, and a new breather cap...... put three quarts of oil in the car, and took to the road. The engine ran great, and after it thoroughly warmed up (and was at idle), I held a folded towel a few inches from both exhaust pipes - and there's no oil coming out of them.

Is it possible that the oil I lost was getting from the valves to the tailpipes? And has the new PCV & breather cap fixed that situation?

Or have I ruined a gasket, or a seal somewhere on the block?
 
WOW! I have never heard of such a thing before. Amazing!
 
I'm thinking the pcv valve was bad and the oil was going through it into the intake then on through. What really gets me is that there was enough oil and the exhaust temperature was low enough that it did not burn all of it off and some ended up out the tailpipe.
 
It's possible as the pressure could build up and push the built up oil past the guides. Were the heads rebuilt? New guides or just knurled? I had this problem with a ferd as they only knurled the guides but it was a cheap rebuild.
 
What he is describing should have put his crankcase in a vacuum not pressure because he had a pvc valve but no way for filtered air to go into the crankcase. Unless the pcv valve was bad the other way and was blocked then the pressure would build up. I thinking in your senario, 64dartwagon it was probably going down the exhaust guides causing the white smoke and not blue smoke from being burned like if it went down the intakes. I'm thinking your right on the guide thing.
 
If it was going thru the pcv then it would cause more of a bluish color and start to hinder performance. Possibly even foul out the plugs. And if the pcv valve was to be lodged shut it will sometimes blow the dipstick out, or even the pcv valve, hopefully before puking a gasket. Now if it get's stuck the other way "open" it would take alot of driving to blow out three quarts, but like you we said it's possible, but I would think it would affect the running more. Best to check the plugs regardless, to be able to keep and eye on that new of a motor.
 
The engine rebuild was actually done almost 20 years ago (by my father - before he passed away in 1990)...... I don't know exactly what he had done to the heads....... maybe nothing - but I'd guess new valve quides, seats, etc. Maybe even new valves. Since he's not around, I can't ask. But knowing how he was, I'd say that the rebuild was totally stock replacement.

Anyway, my Mom let the car sit about 10 years in her garage before giving it to me - which is really very cool, as I was a teenager in the late sixties, and I drove the car back then on dates, etc. Lots of good memories.

BUt getting back to my dilemma, I can't say for sure that I blew out all three quarts of oil that afternoon (when I had the problem) but for sure - some of it certainly escaped. And I WAS seeing SOME white smoke - but not a cloud like broken rings would produce......... I guess its possible that the oil could have blown out through a gasket, coated the underside, and appeared to be leaking from the tailpipes.....

In any case, it drove great after replacing the PCV, oil, and getting a breather. So I'm gonna look under the car for oil on the drivetrain and springs, etc. - then fire it up, and just let it sit in the driveway idling. If oil shows up on the ground under the engine, I'll assume that I did some gasket damage.

Now that I have a breather and a new PCV - I guess that much is resolved. And I'm ceratinly gonna watch my dipstick oil level pretty close.

Thanks for the thoughts.
 
I'd bet you didnt hurt a thing. Just keep an eye on the oil level everytime you drive it and see what its doing. If it is using oil then maybe something got damaged. Id be willing to bet it was sucking oil past the guides or something weird related to the pvc. Your umbrella seals are probably history with 20 years on them by now, anyway.
 
Federal regulations require that vehicles operated by people with lesser standards, exhibit a sign, by either blue smoke or easily and readily available parts found at any quickie mart. Therefore Chevrolet does both just to make sure everyone else is notified when in the presence of these. Safety guideline requirements if I recall correctly. Or somthin
 
Sounds amazing, oil getting into tailpipes. My Valiant had a little bit same kind of problem when I bought her. Previous owner had plugged the other valve cover with oil cap, the other cover had PCV with old cracked grommet. Because of this he had driven the car with low oil level (just below the add -line). I didn't know all this before I happened to add oil. She just went crazy :twisted: : there was oil all over the engine bay, lots of it!! Oil was just bursting through the oil cap, valve cover gaskets etc. I was like WTH :scratch:

I bought two breathers like these . Now I have one breather on both sides, and the PCV is connected to the other breather. That did it, no more leaking, even when there is oil to the max line. What I learned: to do it's job properly, PCV-system needs circulation of air.
 
I wonder if the valve stem seals are cracked ? Since you say the engine was rebuilt some 20 years ago.. Just a thought...
 
My guess is that they are not cracked. But in tiny little pieces in the bottom of the oil pan. Just through age and that tendency to dry out in a week if you don't run it. It's a good suggestion to check the oil next time for chunks, along with cutting open the oil filter.
 
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