Adjustable PCV Valve

Hacksaw · 01-31-2019, 04:17 PM

Quote:

Originally Posted by Ed Wright

I played with those when I still had my flow bench. Mid '70s 454" trucks had the highest flowing I found at that time. Must have been ten years ago. An NHRA Tech guy made me take mine off. I still feel like that is wrong, but I try to follow their directions. My car came with one, still feel like it should have one. Gone now.

OK, we are talking a drag race engine here so why would you want to let crankcase pressure fumes enter the intake side and taint the fresh fuel charge?

Jeff Stout · 01-31-2019, 05:44 PM

I always thought it was a way to build crankcase vacuum. The bonus is the nitro in the oil going into intake charge.

Bench Racer · 01-31-2019, 06:01 PM

Quote:

Originally Posted by Jeff Stout

I always thought it was a way to build crankcase vacuum. The bonus is the nitro in the oil going into intake charge.

Is this better than the sterno on the top of the radiator?

Dragsinger · 01-31-2019, 07:53 PM

The tech sheets show the valve works with an idle vacuum above 7" Most of our stockers or super stockers do not have 7" vacuum idle.

Frank Castros · 01-31-2019, 08:14 PM

Interesting subject, I hope more with contribute to this thread.

Bobby DiDomenico · 02-01-2019, 11:39 AM

Quote:

Originally Posted by Dragsinger

The tech sheets show the valve works with an idle vacuum above 7" Most of our stockers or super stockers do not have 7" vacuum idle.

Who says it has to work? (Or work as the emissions system was designed?;-)
Remember those NASCAR and other intakes with the drilled out mounting studs? This is a lot bigger hole.

Ed Wright · 02-01-2019, 12:41 PM

[QUOTE=Bobby DiDomenico;581432]Who says it has to work? (Or work as the emissions system was designed?;-)

Yeah, and nobody ever clipped a spring, with a restricted engine that, naturally, pulls manifold vacuum @ WOT, right?

Coleydog · 02-01-2019, 02:49 PM

Just like another throttle blade, kinda bad mixture at idle but wide open a good increase, just richen up the jets. Big breather on other valve cover, not much oil spray. Would be interesting to see what cfm goes thru it. I can see why tech would shoot it down.

Ed Wright · 01-31-2019, 10:56 PM

Quote:

Originally Posted by Hacksaw

OK, we are talking a drag race engine here so why would you want to let crankcase pressure fumes enter the intake side and taint the fresh fuel charge?

It's air.

Billy Nees · 02-01-2019, 08:23 AM

Quote:

Originally Posted by Ed Wright

It's air.

^^^^^^^^^^^^^^^^^^^^^^BINGO^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^

Especially in a severely restricted engine.

01-31-2019, 05:44 PM	#2
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,486 Likes: 66 Liked 704 Times in 281 Posts	Re: Adjustable PCV Valve I always thought it was a way to build crankcase vacuum. The bonus is the nitro in the oil going into intake charge.

01-31-2019, 07:53 PM	#4
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: Adjustable PCV Valve The tech sheets show the valve works with an idle vacuum above 7" Most of our stockers or super stockers do not have 7" vacuum idle. __________________ Larry Woodfin 471W

01-31-2019, 08:14 PM	#5
Frank Castros VIP Member Join Date: Nov 2001 Location: The Lowcountry. Posts: 2,959 Likes: 2,548 Liked 2,626 Times in 950 Posts	Re: Adjustable PCV Valve Interesting subject, I hope more with contribute to this thread.

02-01-2019, 12:41 PM	#7
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Adjustable PCV Valve [QUOTE=Bobby DiDomenico;581432]Who says it has to work? (Or work as the emissions system was designed?;-) Yeah, and nobody ever clipped a spring, with a restricted engine that, naturally, pulls manifold vacuum @ WOT, right? __________________ Ed Wright 4156 SS/JA

02-01-2019, 02:49 PM	#8
Coleydog Senior Member Join Date: Jul 2014 Posts: 569 Likes: 36 Liked 53 Times in 38 Posts	Re: Adjustable PCV Valve Just like another throttle blade, kinda bad mixture at idle but wide open a good increase, just richen up the jets. Big breather on other valve cover, not much oil spray. Would be interesting to see what cfm goes thru it. I can see why tech would shoot it down.