Why the change in PCV's location on LT1's
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Why the change in PCV's location on LT1's
I have noticed the early years the PCV was on the drivers side of the manifold then elbows right back into the same side, then later years the PCV was in the same spot but the hose went to underneath/or to the throttle body. Is there a reason GM would do this? Less oil problems?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
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Joined: Jul 2005
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From: Baton Rouge, LA
I have noticed the early years the PCV was on the drivers side of the manifold then elbows right back into the same side, then later years the PCV was in the same spot but the hose went to underneath/or to the throttle body. Is there a reason GM would do this? Less oil problems?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
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Joined: Jan 2005
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From: Moore Oklahoma
I don't like the LT PCV design (fresh air intake passenger's-side and PCV center manifold) which leaves the driver's-side bank somewhat neutral in ventilation. The basic Chevy V8 PCV system uses the fresh air intake on one valve cover and PCV on the other. Additionally, when you have an LT stroker and turn some RPM, you’ll find crankcase back-pressure pushing oil back up the fresh air tube into the throttle body. Therefore, the factory PCV system is not adequate for a full race LT engine
My car is basically a street-legal bracket car which I race almost ever weekend. So, I added breathers on both valve covers to relieve the back-pressure. I also left the PCV valve and tube connected. Some people here on the forum disagree with me on this, however, the local performance engine builders in my area believe I’m correct.
Check-out the previous thread on this subject.
WD
http://web.camaross.com/forums/showthread.php?t=514021
My car is basically a street-legal bracket car which I race almost ever weekend. So, I added breathers on both valve covers to relieve the back-pressure. I also left the PCV valve and tube connected. Some people here on the forum disagree with me on this, however, the local performance engine builders in my area believe I’m correct.
Check-out the previous thread on this subject.
WD
http://web.camaross.com/forums/showthread.php?t=514021
Last edited by The Engineer; Apr 17, 2007 at 07:25 PM.
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From: Baton Rouge, LA
Your setup is not ideal at all for a street car. A) you run the risk of spewing oil all over your valve covers (which btw is because you have issues somewhere else other than your pcv system, likely in your ring setup) and B) is far less than ideal for a modern EFI system, its only really good on an old school carb setup.
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From: Mobile, Ala..USA
The setup works good, but you got to put a restrictor in the fresh air line..stops that backfeeding oil deal. I had one in my 355..intake was clean and all was good...I read it on some board SOMEWHERE
Think I cut off a piece of rod stock, drilled a hole in it and put it in the line. Dont remember the size of the hole.
David
Think I cut off a piece of rod stock, drilled a hole in it and put it in the line. Dont remember the size of the hole.
David
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From: Ocala, Florida
Your setup is not ideal at all for a street car. A) you run the risk of spewing oil all over your valve covers (which btw is because you have issues somewhere else other than your pcv system, likely in your ring setup) and B) is far less than ideal for a modern EFI system, its only really good on an old school carb setup.
The stock PCV system sucks in oil, its that simple, through the fresh air hose, and the PCV line.
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From: Baton Rouge, LA
Unmetered Air. Plus breathers tend to ooze. If your stock pcv system is sucking in oil then somethings wrong with your setup. as I said before, likely an issue with your ring setup
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From: Ocala, Florida
I took out the fresh air hose with the car running and it didn't change the idle at all, so it can adjust to that just fine. And with the PCV still hooked up it is sucking air in through the breathers, the only time where it isn't is at WOT where the pressure is being relieved through them, so that isn't a problem.
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From: Mobile, Ala..USA
HAH now I remember(I think)....I think it was my piston ring manufacturer, Total Seal, that had that in the instructions..if I am not mistaken, hell I am getting old and my part timers is acting up. Hell I dont remember.
David
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From: Moore Oklahoma
Your setup is not ideal at all for a street car. A) you run the risk of spewing oil all over your valve covers (which btw is because you have issues somewhere else other than your pcv system, likely in your ring setup) and B) is far less than ideal for a modern EFI system, its only really good on an old school carb setup.
With my PCV valve "still operational", at low RPM (normal operation) fresh air is drawn-in through both valve cover breathers, in-place-of the OEM fresh air tube. Therfore, no real change in crankcase ventilation theory. Then at high RPM, any excess crankcase back-pressure is then released through the breathers.
WD
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From: Mobile, Ala..USA
I guess all the LT1's and LS1's from the factory have something wrong with them then. I took out the fresh air hose with the car running and it didn't change the idle at all, so it can adjust to that just fine. And with the PCV still hooked up it is sucking air in through the breathers, the only time where it isn't is at WOT where the pressure is being relieved through them, so that isn't a problem.
I took out the fresh air hose with the car running and it didn't change the idle at all, so it can adjust to that just fine. And with the PCV still hooked up it is sucking air in through the breathers, the only time where it isn't is at WOT where the pressure is being relieved through them, so that isn't a problem.The hose on the passenger side will not have any pull on it, nor will the port, I think it only works on throttle opening to pull air from the hose into the TB.
David
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From: Ocala, Florida
I have no idea what you are saying here. The hose under the throttle body pulls air from the crankcase into the intake manifold. Under normal driving conditions this makes hte fresh air hose flow from the tb into the valve cover, but at WOT, the flow reverses and it flows from the valve cover to the throttle body to relieve crankcase pressure, and that is when oil enters the throttle body. Under normal driving the PCV is constantly sucking air out of the crankcase, so under those conditions is is always sucking oil vapors into the intake, which is why I have a catch can in line with the PCV, and I took off the fresh air hose and am running 2 brethers like The Engineer.
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From: Moore Oklahoma
I have no idea what you are saying here. The hose under the throttle body pulls air from the crankcase into the intake manifold. Under normal driving conditions this makes hte fresh air hose flow from the tb into the valve cover, but at WOT, the flow reverses and it flows from the valve cover to the throttle body to relieve crankcase pressure, and that is when oil enters the throttle body. Under normal driving the PCV is constantly sucking air out of the crankcase, so under those conditions is is always sucking oil vapors into the intake, which is why I have a catch can in line with the PCV, and I took off the fresh air hose and am running 2 brethers like The Engineer.
WD
Last edited by The Engineer; Apr 17, 2007 at 08:37 PM.
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From: PA
I have noticed the early years the PCV was on the drivers side of the manifold then elbows right back into the same side, then later years the PCV was in the same spot but the hose went to underneath/or to the throttle body. Is there a reason GM would do this? Less oil problems?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
Also, GM has a newer PCV valve that they use in the LSx engines, and it doesnt have the ball inside as it is silent? Any word on what the benifit of this could be to LT1/4's?
i have a 97 lt1 and the pcv valve has no ball...
i wondered this before but now i am really curious...
should i have a ball or did some 97 lt1's not come with them?
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From: Moore Oklahoma
WD
