Got 514 problems!

[Back in Black]

To clarify the PCV is run into the intake and has a high quality billet aluminum breather on the opposite valve cover to pull fresh air from

What I thought was oil smoke must have mostly been simply rich running. There's no sign of oil burning in that engine and it looks to be fine. Plugs look nice and dry

The person dynoing and programming my car was the problem.. although highly recommended by several people and seemingly a well set up shop he (The owner) apparently knew less about this specific issue than I do, which is to say not much. That's the optomistic view of his intents. I'm just going to move on and get someone to properly program my ECU so I can finally drive my machine

The shop also knocked my front bumper out of true (shoved in on one side) but that's another issue and no doubt easy to fix. I only noticed it after I got home tonight

[ByronRACE]

Sorry, but the pistons moving around in the crank case do not cause the crank case to "pump up" and build pressure. Sure, when a piston moves down the bore it displaces air...and if all 8 were moving down the bore at the same time, you'd create quite an air compressor. That would be a very stupid design, and amazingly enough...they figured this out way back in the beginning and designed around it ever since. As one piston moves down, another moves up, keeping the volume and pressure in the crank case constant. Yes, turbulent...but constant on average.

If this "pumping crankcase" theory was correct, every "sealed system" engine (just about every single engine built since 1980, probably even earlier) would blow the PCV out as well as the pan and intake gaskets, shoot oil out the front and rear seals, etc. This doesn't happen, right.

The truth of the matter is, if you're building crank case pressure, it's combustion pressure coming past the rings. Sounds scary, but every engine does this to some degree, and the larger the displacement and higher the compression, the more this will occur. Newer engines leak more as well. On a 514, a single factory style breather isn't sufficient at wide-open-throttle. One or two open element breathers (as suggested) should do the job. In addition, the more breathers you put on the crank case the better. Every time you double the area of the breather path to the crank case, you cut the velocity of the air flow out the breather in half. Air velocity is what carries the oil out of the breather.

I have a pair of -10 lines running from the valvecovers of my blown 435" bbf, and I have no crankcase pressure at WOT. It does vent some, and I do see some "fog" at fire up as well as some oil fog at WOT. The fog at fire up is steam/moisture/condensation that goes away when the engine warms. The fog at WOT is oil vapor, combustion gasses, etc..."blow-by". With just one -10 line venting the engine, I see about 1/4 psi (data logger) at wot. With two, it's zero. I keep my eye on it...it's an early warning system in the event I were to crack a ring or damage a piston.

[fordracer]

Originally Posted by ByronRACE

Sorry, but the pistons moving around in the crank case do not cause the crank case to "pump up" and build pressure. Sure, when a piston moves down the bore it displaces air...and if all 8 were moving down the bore at the same time, you'd create quite an air compressor. That would be a very stupid design, and amazingly enough...they figured this out way back in the beginning and designed around it ever since. As one piston moves down, another moves up, keeping the volume and pressure in the crank case constant. Yes, turbulent...but constant on average.

If this "pumping crankcase" theory was correct, every "sealed system" engine (just about every single engine built since 1980, probably even earlier) would blow the PCV out as well as the pan and intake gaskets, shoot oil out the front and rear seals, etc. This doesn't happen, right.

The truth of the matter is, if you're building crank case pressure, it's combustion pressure coming past the rings. Sounds scary, but every engine does this to some degree, and the larger the displacement and higher the compression, the more this will occur. Newer engines leak more as well. On a 514, a single factory style breather isn't sufficient at wide-open-throttle. One or two open element breathers (as suggested) should do the job. In addition, the more breathers you put on the crank case the better. Every time you double the area of the breather path to the crank case, you cut the velocity of the air flow out the breather in half. Air velocity is what carries the oil out of the breather.

Then explain why when the PCV gets plugged up or totally removed oil will be blown up into the air filter?? In fact I am so positive about this I'll give you some homework.

Go out to your car and start it up. Plug the hole in the valve cover where the PCV goes. Plug the hole or holes where the breather element or tube is. Rev the car to 2500 rpm and see how long it takes to blow out every seal in the engine.

[ByronRACE]

If the crank case isn't ventilated and the PCV is the only exit path for pressure, then yes...if you block the last remaining exit path, the blow-by will pressurize the crank case to the point where it'll blow oil past the front and rear seals. If that's not a good enough vent, it will blow out the end gaskets on the intake next usually. Not the best thing to try.

Big stroker engines, high compression, or anything else that increases blow-by more than what a normal production engine sees needs a bigger ventilation system. If you want to run a PCV system, then you probably need more than one PCV valve to make a large enough exit path. And even then, keep in mind that your engine is sucking crankcase vapor containing oil...with is a very low octane fuel and induces detonation. Personally, I say forget the PCV and run an open crankcase unless the PCV is required. If you want crankcase vacuum, use a vacuum pump or a header evac system.