Breather plus pcv?
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 8,721
Likes: 108
From: Canada
Breather plus pcv?
I have some Edelbrock valve covers which have curious on each, passenger side pcv and driver a breather. My engine is a 383 stoker pushing just under 500 hp when running the Holley 750 mech dp and properly tuned (10.5 : 1 compression). I'm not taking it to the track anymore and just dropped an Edel Performer (750 mech dp) on it for cruising as I need to rebuild the Holley. With the breather I am getting some oil coming out of it, not a lot but it will pool on my intake after a long cruise. I am adding 1 qt of oil every 1000 miles so not burning much at all. Do I need to keep the breather in to balance or would the pcv valve on one side suffice?
It is the original block (Lt-1/Zr-1) 60 over with a sleeve in one cyl. This old gal does have a racing history and am at the point where I am holding off doing any major work as will eventually drop an ls2/3 with 5 sp plus ac in in a few yrs and crate the original engine and rock crusher tranny. Car won't be sold as I've promised it to my son when I can no longer drive it. Hopefully another 15 -20 yrs as I am 56 now. Have owned the vette since '98 and rebuilt the engine in '01. So guys what about this breather, do I need it or just put a plug in it. I have the original heads, valve covers and intake stored away as well.
It is the original block (Lt-1/Zr-1) 60 over with a sleeve in one cyl. This old gal does have a racing history and am at the point where I am holding off doing any major work as will eventually drop an ls2/3 with 5 sp plus ac in in a few yrs and crate the original engine and rock crusher tranny. Car won't be sold as I've promised it to my son when I can no longer drive it. Hopefully another 15 -20 yrs as I am 56 now. Have owned the vette since '98 and rebuilt the engine in '01. So guys what about this breather, do I need it or just put a plug in it. I have the original heads, valve covers and intake stored away as well.
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
PCV, means positive crankcase ventilation...you are pulling a vacuum from the carb to suck vapor fumes into the incoming airstream to be burned. It eliminated the old road draft tube down the back of the engine. You need some way to let fresh air into the engine...thus, the aptly named 'breather' is a requirement. Usually the PCV is on one valve cover, the breather on the other.
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 8,721
Likes: 108
From: Canada
Yup, thanks guys that is what I thought. Would be some blowby that I am getting but just don't want to do the rings right now. When we built the engine I just ran a tube out and under the engine maybe will go back to that'd keep the oil off the top of the engine. As I said it's not much and after 10 yrs. 25000 miles things could be a lot worse.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
With most PCV systems, the fresh 'vent' air is supplied from a hose coming from the air cleaner housing and going to the rocker cover which does not have the PCV valve installed in it. That prevents the oily mist problem that is present with a breather.
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 8,721
Likes: 108
From: Canada
Interesting drive, heading up to cottage country (Wasaga Beach) a Ministry of Environment guy pulled me over to check engine. Need a ccv, evap and maybe air system according to his manual. At least he didn't ticket me, so the answer in Ontario is no air breather allowed must be ccv. He was a decent guy so I'm not complaining about him at all. In a few weeks there is a huge Corvette wknd at Wasaga, they will be checking that all smog equip't is there I'm told.
Last edited by gdh; Aug 4, 2011 at 08:05 PM.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
You can add a breather filter like this to your air filter assembly and attach a tube or hose from the passenger side breather hole grommet in the valve cover to it. Any parts store has it and the clip. That will make your pcv systen work like factory and make it ccv. It was used on 99% of all GM of that era.
As far as the air system, if you don't have it, good luck in finding one, but if they don't do a emissions test, then it really doesn't have to work.
You might want to carry a copy of the factory AIM and carry it with you.
As far as the air system, if you don't have it, good luck in finding one, but if they don't do a emissions test, then it really doesn't have to work.
You might want to carry a copy of the factory AIM and carry it with you.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 8,721
Likes: 108
From: Canada
You can add a breather filter like this to your air filter assembly and attach a tube or hose from the passenger side breather hole grommet in the valve cover to it. Any parts store has it and the clip. That will make your pcv systen work like factory and make it ccv. It was used on 99% of all GM of that era.
As far as the air system, if you don't have it, good luck in finding one, but if they don't do a emissions test, then it really doesn't have to work.
You might want to carry a copy of the factory AIM and carry it with you.
As far as the air system, if you don't have it, good luck in finding one, but if they don't do a emissions test, then it really doesn't have to work.
You might want to carry a copy of the factory AIM and carry it with you.
