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ok, ive seen this on speed boats and other high zoot stuff like that. does having the crankcase vapors goin to the headers do anything for performance, or is it just another way to get rid of haveing a PCV?

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"but its that gut feeling of you're drawn to what feels right for yourself and what you're passionate about..."

I believe this is done to help eliminate crank case pressure. The exhaust acts as a siphon of sorts and actual draws the pressure out. I've read this is of little use unless you are pumping out big HP numbers.

I'd make sure to have a check valve in the tubes, I wouldn't want superhot exhaust, worse yet, some sort of flame if it were to happen shoot into the crankcase and cause a fire somehow.

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-Old ride-82 Luv diesel 5spd with some upgrades
-Past rides-82 Sierra, 78 Coupe De'Ville, 91 2dr Blazer, 86 RX7, 86 Porsche 944T (rear-ended and totaled)
-Curr. rides- 1970 Ford LTD 4dr, 390 4Bbl, 2nd owner! With a few Extras 00' Civic beater...

well no, the header venting thing os a kit. they have 2 oneway valves per side. one of ems a baffle lookin one on the valve covers and then theres one on or by the collector thats like the deal on and emissions motor.

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"but its that gut feeling of you're drawn to what feels right for yourself and what you're passionate about..."

Basically, like was said already, the idea is to reduce crankcase pressure. There are other ways to do this. Everything from a PCV to connecting an actual vacuum pump up to your crankcase. The exhaust method is popular because it's believed to be "free" vacuum. In other words, no horsepower is lost while the vacuum is created.

The reduction of crankcase pressure is said to have a couple advantages. I can't come up with proof on any of these, nor can I provide any personal experience, but here are some theories I've heard:

-Less pressure = less air = less wind drag on fast moving rotating components

-Less pressure in theory will create a higher pressure differential between the chamber (top of piston) and the crankcase (bottom of piston), thus causing the rings to seal tighter against the base of the rings grooves in the pistons. This would theoretically cause more power due to losing less of the combustion past the rings.

-Less pressure reduces the amount of foaming/oil mist and/or windage drag from the oil in crankcase and thus less liquid drag against rotating components. Some people even report that if too much vacuum is used, wrist pins begin to fail due to lack of oil.

-Oil leaks are reduced or prevented because the crankcase pressure would be lower than atmosphere pressure, so any leak would only let air into the motor rather than letting oil/air leak out of the motor.

Whatever theory you like, people typically report up to a 5% increase in horsepower by adding a vacuum pump that maintains 12" of vacuum. The header style do not create as much vacuum as a pump, but would probably do something beneficial.

Nice info Ben, and people say I'm the encyclopedia.

I think the whole idea "sucks".....

Just kidding, it sounds really smart and makes sense to me.

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OK, I'm over it. Where's the beer?

I think the best advantage to having a pcv system is that it helps keep the oil clean. This is from a daily driver standpoint. Spent crankcase vapor is drawn in to the combustion chamber and burned away. With clean air steadily drawn in to the crankcase, spent gases are slower to blend with the oil so it stays cleaner longer. Years ago it was common to find just a simple vent tube that ran from the crankcase down to the vehicles undercarrage. The tube end would run straight back with a baloney cut on the end. This was supposed to siphon crankcase vapor out. It didn't do much good in traffic. With the introduction of using a check valve pcv system, a noticable benefit was the fact that the oil would stay cleaner.
If you're not constantly opening the motor to adjust valves and such, i'd recommend that you use a pcv system.

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Previous setup: 4.1 Buick V-6/TH 350
Current setup: 400 Small Block Chevy V-8/TH 350
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