[crdewolf]

I have a newly rebuilt motor in my Firebird--professionally rebuilt using parts sourced by Butler. upon initial drive, it was blowing smoke after heavy decelleration, and I finally figured out that it was coming from the PCV valve. after several attempts to address--I added a second breather (opposite the oil filler cap which was the only primary breather before prior to the rebuild). And ultimately reduced the effectiveness of the PCV Valve by stuffing foam in the grommet. Now, I'm getting visible smoke out both breathers, AND oil is actually coming out through the breathers. over the valve covers on to the exhaust--after a few short miles-- causing a smoky, smelly mess.

At this point, I think my options are: 1) get an oil/air separator tank between PCV Valve and carb, 2) get a new valley pan or 3) see if the STOCK valley pan fits over my roller rockers.

What is the easiest/cheapest option? or is there another? I never had this problem pre-rebuild!!! I still have the stock valley pan...will this fit over my lifters?

Specs: 67 400 motor bored to a 409 (not stroked), Butler Valley pan with PCV Grommet at the front (vs the rear as stock--and they claim doesn't take oil), Edelbrock D port heads 72 cc, 10:1 compression
Edelbrock 800 cfm carb, 2 breathers--one in each valve cover, although one is the original oil filler cap. Comp Cams Hydr Roller cam and lifters 224/230 Duration with 501/510 lift

[gtofreek]

That valley pan you are using does not work for controlling oil usage through the PCV. I would re-install the original. If you have roller lifters, you may need to dimple the inside of the valley pan to clear them. Otherwise, Tomahawk products has a valley pan that supposedly clears roller lifters.

How did you break-in the rings? I like to accelerate hard, a few times from 30-60 MPH or so. This builds pressure behind the rings to force them out against the cylinder wall to seal. If you have been babying it, the rings won't seal good and you will have more blow-by.

[Joel Koontz]

How many miles on the motor?

Agree with gtofreek on break-in. SHORT bursts of hard acceleration without keeping the rpms high for very long. Get on it at every other stop sign/light.

What do you mean when you say "figured out that it was coming from the PCV valve"?

If it is blowing smoke at full throttle. Probably not from the PCV valve.
PCV valve is not doing much, if anything, at full throttle(no/low vacuum).

If it is a valley cover with no baffle, many have reported that they let oil be sucked out of the engine INTO THE INTAKE and cause the engine to BURN oil.

You may have two separate issues, but to cure the blow by issue(out the Valve Cover Breathers) you may just need to "beat on the car" some to get the rings fully seated.

[crdewolf]

Well, I haven't been babying it. Less than 1,000 miles on the motor. I found it to be the PCV valve through process of elimination. It was blowing oil only on DECELLERATATION with throttle lift off. At that point, my rear view mirror was thick with white smoke. upon disconnecting the PCV Valve, that smoke disappeared, but then the other problems came about as I described earlier

[geeteeohguy]

Classic excessive blowby past the piston rings. Rings haven't seated or are damaged. A leakdown test will confirm this. Not a PCV problem.

[gtofreek]

The only PCV problem he has is the fact that the valley pan is not baffled. PCV's only work at light throttle positions. Under heavy acceleration, there is no vacuum for the PCV to work so pressure builds up and blows oil out the breathers. This is where EVAC systems work in drag cars.

In street cars, I would recommend setting up the system like the factory did with a hose running from the valve cover to the air cleaner so it has some suction under wide open throttle, and get rid of the breathers in the valve covers. That just gives the oil someplace to blow out.

[Tom Vaught]

Originally Posted by gtofreek

The only PCV problem he has is the fact that the valley pan is not baffled. PCV's only work at light throttle positions. Under heavy acceleration, there is no vacuum for the PCV to work so pressure builds up and blows oil out the breathers. This is where EVAC systems work in drag cars.

In street cars, I would recommend setting up the system like the factory did with a hose running from the valve cover to the air cleaner so it has some suction under wide open throttle, and get rid of the breathers in the valve covers. That just gives the oil someplace to blow out.

X2

Tom Vaught

[77 TRASHCAN]

Without a baffled valley pan, you might just as well take the PCV valve off the end of the hose, and run the hose into the oil pan sump, close to same...

[lust4speed]

Originally Posted by geeteeohguy

Classic excessive blowby past the piston rings. Rings haven't seated or are damaged. A leakdown test will confirm this. Not a PCV problem.

Agreed. Since crdewolf has eliminated the PVC and still has a big problem, then rings are the likely source. I'd also say that the amount of oil being expelled is way beyond just a baffle fix. The leakdown test would be my choice also; but with this much blowby, even a compression test could be enough to pinpoint one or more cylinders causing the problem.

[gtofreek]

Without a PCV valve in the system[or some type of vacuum source], the engine will develop extreme amounts of crankcase pressure and blow oil out everywhere it can.

Crankcase pressure is always being generated, even with perfectly sealing rings. Every time a piston goes down a cylinder under combustion, it blows pressure into the crankcase. Another piston going up a cylinder at the same time does not displace the same amount of air since it is not under combustion pressure, but rather compression, or pushing exhaust out, which is also trying to force small amounts of pressure past the rings, thus adding to the pressure situation.

I bet that if he fixes the valley pan and eliminates the breathers, and runs a tube to the air cleaner, his problems will go away.

Did you ever see a factory engine with breathers in the valve covers and no PCV? I'm not talking about old engines with road draft tubes either.

[lust4speed]

Partially agree, but at anything over moderate power levels, the PCV valve won't be doing anything since manifold vacuum will be low. At full throttle where the blow-by is the worse, the PCV system won't be doing anything. The breathers and/or the vent tube to the air cleaner will have to handle the blow-by. Only benefit of the vent tube is it might mask the problem slightly since the oil mist will be re-cycled through the combustion process.

[steve25]

There may be multiple problems here.
Just because the motor was put togethere by a builder does not mean that a a ring could not have been broken on piston installation, or the oil rail gaps where not spread 180.
Where the heads ported, does the valve cover bolt hole or the Intake rocker stud holes break into the ports, if so sealer needs to be put on those items when threaded in.

[FrankieT/A]

Are we sure the rings are right side up?

[crdewolf]

To help clarify the situation...below is a link to a :30 video of the FIRST TIME i took the car around the block after assembling it. Note the white smoke at the end of block as I decellerate. Second, the engine was made up entirely of Butler prepared parts and assembled by Watson Racing here in CA. They do dozens of pontiac engines per year, and come strongly recommended by Butler. I have a hard time believing they put the rings in upside down

http://www.youtube.com/watch?v=J4E702ZKBWA

[lust4speed]

Do you have a crossover or X-pipe on the exhaust?

[laurasgto65]

what was the part no. of the valley pan im thinking of one to but dont need any smokein problems

[screamingchief]

Compression test dry/wet,then a leakdown test,SOP diagnostic testing in a situation like this,even on a fresh build.

That should answer the ring ???? with a good sense of certainty.

Also agree the Bulter valley pan wont work w/the PCV,that's already been shown here time & time again,either need to switch to an OE valley pan -or- move the PCV valve to the breather like they did with the 455 SD engines.

Also agree,running a vent tube from the correct style of breather/oil seperator to the air cleaner is a good idea as well.

Funny how some never seem to have these sorta problems,and other's always seem to have these kinda problems.

HTH

Bret P.

[dmac]

Agree with others- first and easiest is a compression check on all cylinders with all spark plugs removed. That will tell you where to look next. There is a general sequence of tests you do in order from easiest to hardest to diagnose problems.

[steve25]

When you pull the plugs make a close inspection and note if all of them show signs of oil, or only some.
If only some than tag them for the cylinder they came from.

[gtofreek]

From what I am understanding, it does not smoke under acceleration. Correct me if I'm wrong, but he says it smokes on de-acell, which is classic PCV sucking oil, or valve seals leaking. High vacuum, high oil suckage. Sounds to me like he just needs to fix the pcv system and be done with it. If that doesn't fix it, I would look intop checking the valve seals.

Everyone is trying to make out like he has a bad engine when I'm not hearing any symptoms of a bad engine. Bad rings would smoke under hard acceleration, not on de-accell.