PCV Question
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Teching In
Joined: Feb 2017
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PCV Question I have a Gen III LS1/LS6 383 stroker build. Track use car.
LS1 block.
It has LS6 valve covers and valley pan.
PCV vents from the valley pan into a catch can with a breather on top (Moroso). It does NOT feed back into the throttle body (I just empty the catch can regularly).
Right now the nipple from the top of the passenger side valve cover that normally plumbs to the throttle body is blocked off on both the valve cover and the throttle body.
The question is, is it necessary to feed fresh air into the valve cover? Or, is that simply part of the engineering for emissions purposes?
As it stands now, crank case venting is done through the valley pan. My concern is that if I reconnect the valve cover to the throttle body, as it was designed, that i will push oil into the throttle body during hard deceleration and prolonged cornering. The hose will basically back flow oil from the valve cover into the throttle body.
Since this is a track car, I'm not overly concerned about emissions... Just sayin...
Thank you for your response!
Jeff
LS1 block.
It has LS6 valve covers and valley pan.
PCV vents from the valley pan into a catch can with a breather on top (Moroso). It does NOT feed back into the throttle body (I just empty the catch can regularly).
Right now the nipple from the top of the passenger side valve cover that normally plumbs to the throttle body is blocked off on both the valve cover and the throttle body.
The question is, is it necessary to feed fresh air into the valve cover? Or, is that simply part of the engineering for emissions purposes?
As it stands now, crank case venting is done through the valley pan. My concern is that if I reconnect the valve cover to the throttle body, as it was designed, that i will push oil into the throttle body during hard deceleration and prolonged cornering. The hose will basically back flow oil from the valve cover into the throttle body.
Since this is a track car, I'm not overly concerned about emissions... Just sayin...
Thank you for your response!
Jeff
As long as the size of the lines or the openings are adequate enough to relieve the pressure in the crankcase you should be good. On the 427 I've got 10AN lines of each valve cover to a Moroso breather can with everything capped off but the brake booster. I never see oil collecting in the breather can like you see when using sealed catch cans either just mostly condensation from running the car in colder weather.
TECH Apprentice
Joined: Oct 2016
Posts: 321
Likes: 30
From: Massachusetts
I have a Gen III LS1/LS6 383 stroker build. Track use car.
LS1 block.
It has LS6 valve covers and valley pan.
PCV vents from the valley pan into a catch can with a breather on top (Moroso). It does NOT feed back into the throttle body (I just empty the catch can regularly).
Right now the nipple from the top of the passenger side valve cover that normally plumbs to the throttle body is blocked off on both the valve cover and the throttle body.
The question is, is it necessary to feed fresh air into the valve cover? Or, is that simply part of the engineering for emissions purposes?
As it stands now, crank case venting is done through the valley pan. My concern is that if I reconnect the valve cover to the throttle body, as it was designed, that i will push oil into the throttle body during hard deceleration and prolonged cornering. The hose will basically back flow oil from the valve cover into the throttle body.
Since this is a track car, I'm not overly concerned about emissions... Just sayin...
Thank you for your response!
Jeff
LS1 block.
It has LS6 valve covers and valley pan.
PCV vents from the valley pan into a catch can with a breather on top (Moroso). It does NOT feed back into the throttle body (I just empty the catch can regularly).
Right now the nipple from the top of the passenger side valve cover that normally plumbs to the throttle body is blocked off on both the valve cover and the throttle body.
The question is, is it necessary to feed fresh air into the valve cover? Or, is that simply part of the engineering for emissions purposes?
As it stands now, crank case venting is done through the valley pan. My concern is that if I reconnect the valve cover to the throttle body, as it was designed, that i will push oil into the throttle body during hard deceleration and prolonged cornering. The hose will basically back flow oil from the valve cover into the throttle body.
Since this is a track car, I'm not overly concerned about emissions... Just sayin...
Thank you for your response!
Jeff
I also upgraded the ls6 valley pan with the built in PCV system. On the older ls6 valley pans, the pcv system doesn't have the pcv valve built in. The newer ones do. If yours has the pcv valve, that's a one way system. It only vents towards the catch can/breather and can't draw in fresh air. I believe you can't draw in fresh air right now. Of course, I think drawing in fresh air is less important than venting out excess pressure. If I were in your situation, I would just put in a simple breather on that valve port, or even a dirt cheap amazon catch can and run it inline to the throttle body.
Also, here's another idea. I have a procharger and the kit relocates that tube from the throttle body to before the supercharger because of the forced induction. So basically.....it doesn't even need to be tied into the throttle body. You can just run a tube with a breather. I suppose you can even have a hose with a simple filter facing down so any oil will just fall to the ground.
Anyways, that's my understanding. Hopefully someone who knows what they're talking about can chime in if I'm out of my mind.
Last edited by 2001ws6ft; Jun 9, 2021 at 10:44 PM.
