CrankCase Evac System
Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 6,080
Likes: 0
From: Houston TX
CrankCase Evac System
Would removal of PCV, and addition of CCE ( dumped into the headers ) create too much negative pressure? If I run a old school breather filter in liu of the oil cap, shouldnt that let enough fresh air in to keep from blowing seals up. Thanks
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Here is another post, see what he says about this:
The hypothesis:
For the past month I decided to run just breathers on each of the valve covers to see if I can get the crankcase gas out faster than a catch can and PCV.
The results:
Not a good idea. It seems that even with the breathers on each valve cover and no PCV, the LS1 could not vent get the crankcase fumes out fast enough. I got alot of oil build up on the inside of my oil cap. I also got alot of build up inside the hoses which I used to connect the breathers to the valve cover. Kinda looks like tootpaste inside the hose. When I turn the engine off after driving, I pop off the oil cap and alot of crankcase gas would come out. It would stop after 5 min or so. Thats alot of gas that could not make it out.
My conclusion:
I've concluded that the LS1 needs a vacuum source to pull the crankcase gases out via intake or pump. If there is no vacuum source present, the engine will turn into a giant oil catch can and eventually your blow your engine seals. I re-installed my catch can and now I have no more crankcase fumes coming out when I pop off my oil cap.
The hypothesis:
For the past month I decided to run just breathers on each of the valve covers to see if I can get the crankcase gas out faster than a catch can and PCV.
The results:
Not a good idea. It seems that even with the breathers on each valve cover and no PCV, the LS1 could not vent get the crankcase fumes out fast enough. I got alot of oil build up on the inside of my oil cap. I also got alot of build up inside the hoses which I used to connect the breathers to the valve cover. Kinda looks like tootpaste inside the hose. When I turn the engine off after driving, I pop off the oil cap and alot of crankcase gas would come out. It would stop after 5 min or so. Thats alot of gas that could not make it out.
My conclusion:
I've concluded that the LS1 needs a vacuum source to pull the crankcase gases out via intake or pump. If there is no vacuum source present, the engine will turn into a giant oil catch can and eventually your blow your engine seals. I re-installed my catch can and now I have no more crankcase fumes coming out when I pop off my oil cap.
Racer
Joined: Oct 2007
Posts: 359
Likes: 0
From: Long Island NY
Here is another post, see what he says about this:
The hypothesis:
For the past month I decided to run just breathers on each of the valve covers to see if I can get the crankcase gas out faster than a catch can and PCV.
The results:
Not a good idea. It seems that even with the breathers on each valve cover and no PCV, the LS1 could not vent get the crankcase fumes out fast enough. I got alot of oil build up on the inside of my oil cap. I also got alot of build up inside the hoses which I used to connect the breathers to the valve cover. Kinda looks like tootpaste inside the hose. When I turn the engine off after driving, I pop off the oil cap and alot of crankcase gas would come out. It would stop after 5 min or so. Thats alot of gas that could not make it out.
My conclusion:
I've concluded that the LS1 needs a vacuum source to pull the crankcase gases out via intake or pump. If there is no vacuum source present, the engine will turn into a giant oil catch can and eventually your blow your engine seals. I re-installed my catch can and now I have no more crankcase fumes coming out when I pop off my oil cap.
The hypothesis:
For the past month I decided to run just breathers on each of the valve covers to see if I can get the crankcase gas out faster than a catch can and PCV.
The results:
Not a good idea. It seems that even with the breathers on each valve cover and no PCV, the LS1 could not vent get the crankcase fumes out fast enough. I got alot of oil build up on the inside of my oil cap. I also got alot of build up inside the hoses which I used to connect the breathers to the valve cover. Kinda looks like tootpaste inside the hose. When I turn the engine off after driving, I pop off the oil cap and alot of crankcase gas would come out. It would stop after 5 min or so. Thats alot of gas that could not make it out.
My conclusion:
I've concluded that the LS1 needs a vacuum source to pull the crankcase gases out via intake or pump. If there is no vacuum source present, the engine will turn into a giant oil catch can and eventually your blow your engine seals. I re-installed my catch can and now I have no more crankcase fumes coming out when I pop off my oil cap.
That dosent answer the question, he just used breathers. Crankcase evac is plumbed into both headers with check valves to pull the vapor out, the exhaust heat burns up any gases that the system evacuates. I used to run those on my race car and they did work fairly well, but its a matter of tapping into both valve covers, 1 may not be enough. If thats the case what do u do with the coils?
Thread Starter
Le Mans Master
Joined: Oct 2006
Posts: 6,080
Likes: 0
From: Houston TX
Ok here the idea, excuse my crappy drawings. i borrowd the motor pics as I dont have any of mine that show without valvecovers.
Or in lieu of getting a second catch can, I could run the drivers side into the one and evac from one location instead of 2.
Or in lieu of getting a second catch can, I could run the drivers side into the one and evac from one location instead of 2.
Racer
Joined: Oct 2007
Posts: 359
Likes: 0
From: Long Island NY
Nice idea, looks like it will work but personally if i was going to do that id run the breathers into the collectors so you have the exhaust from all 8 cylinders pulling the vapors out. Your way will probly work but i dont think you will see the results you are looking for.....just my $.02. However you can try it your way and just see what happens...never know
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
Would not work....you are to close to the exhaust port & would get reversion waves pushing back in. The only way to evac to the headers is in the collector it'self...and the tube must act as a venturi to "draw" the vapors out. Also, on a street application you would only have vacum at high speed, you need consant negative pressure that is metered or controlled with either a PCV valve, or a adjustable vacum relief valve. Best if deviating from stock is a breather with filter on say the oil filler cap (we are designing a billet one to directly replace your stock fill cap), draw from the drivers side vent, through a baffeled catch can for effective seperation, and then to the stock style PCV valve at the stock location.
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Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
If you used an open, filtered breather on the oil cap then there will be virtually no vacuum inside the crankcase because fresh air will replace any dirty air volume sucked out of the crankcase. The CCE will be the vacuum source instead of the intake manifold, and crankcase evacuation will occur effiectively if the CCE can produce enough vacuum to get a good flow through the crankcase.
Last edited by ZeeOSix; Mar 21, 2008 at 06:42 PM.
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
Pro
Joined: Oct 2004
Posts: 566
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From: Miami FL
CI 7 & 9 Veteran
More questions
What about some spirited driving above 3000 RPMs or more? Will I be causing damage due to un-equal or high pressures in the crank case or intake manifold?
I've been running without one for a while and am concerned
about causing expensive damage to my engine.
I've been running without one for a while and am concerned
about causing expensive damage to my engine.
Le Mans Master
Joined: Aug 2001
Posts: 8,145
Likes: 1
From: Bradenton FLORIDA
