Effects of no PCV system?
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
Effects of no PCV system? I just wanna go the old school route and run duel breathers.I dont drive the car much,change the oil very frequently and its basically a race car.What are the ill effects of doing this on my car other than getting the oil dirty faster?
Wow here runs no pcv on there strip/street cars..
Wow here runs no pcv on there strip/street cars..
Maybe a few HP... I believe the PCV system relieves more crankcase pressure than just a breather alone since it has manifold vacuum applied to it. So you "could" lose a few HP due to more drag on the engine. Although I don't have anything to back it up at the moment. Maybe someone else will chime in. Good luck.
At WOT there is no vacuum from the intake manifold. More pressure is released through the breathers at WOT. The only drawback is a little oil steam from the breather if you rings are not perfect (most stock bottom ends will puff some from the breather) and it makes a slight dust on the motor. I am running a metco breather on the pass valve cover and pulled the PCV valve out and replaced it with a breather while plugging the vacuum port in the intake.
Brad
Brad
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
I have file fit rings in my car and the block was honed w/a deck plate.Thanks for the info,are u running the fresh air tube into the tb/ps valvecover or that plugged too.
Yeah I am still running the fresh air tube. I need to pull the TB and see if there is any oil getting in from there. I don't see why it should be.
You may see a little steam untill the rings seat but that all depends on the finish of the cylinder walls.
Brad
You may see a little steam untill the rings seat but that all depends on the finish of the cylinder walls.
Brad
I run:
-Metco breather on passenger cover replacing oil fill cap
-plugged tb inlet
-plugged intake inlet
-pcv in driver's side routing to passenger rear inlet
-capped front passenger side outlet
I am running a blower and have a 9:1 forged engine.
I am getting some smoke from the breather.
When I had my 422ci iron block I ran the same setup but with a breather in back instead of a pcv in the back of the driver's side cover.
-Metco breather on passenger cover replacing oil fill cap
-plugged tb inlet
-plugged intake inlet
-pcv in driver's side routing to passenger rear inlet
-capped front passenger side outlet
I am running a blower and have a 9:1 forged engine.
I am getting some smoke from the breather.
When I had my 422ci iron block I ran the same setup but with a breather in back instead of a pcv in the back of the driver's side cover.
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Just the way they should Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
John I dont understand why u have the PCV tied together if u dont have it hooked to the intake?
How is is working this way?
U arent hooked to a vacum source so it has no way of drawing it out of the motor?
How is is working this way?
U arent hooked to a vacum source so it has no way of drawing it out of the motor?
TECH Addict
Joined: Dec 2001
Posts: 2,298
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From: new england
PCV applies vacuum at part throttle to crankcase, this negative pressure helps to balance pressure in comb. chamber above piston rings to keep rings seated and oil scraping ability functioning. You will use more oil with only venting of crankcase, instead of functioning pcv. Oil seals will be less effective also w/out pcv.
I ran the LS6 PCV setup and one breather on the last motor... everything plugged off. No oil usage issues ran good... this new motor will have dual breathers and the LS6 PCV. Eventually a vaccum pump....
Originally Posted by LS1derfull
PCV applies vacuum at part throttle to crankcase, this negative pressure helps to balance pressure in comb. chamber above piston rings to keep rings seated and oil scraping ability functioning. You will use more oil with only venting of crankcase, instead of functioning pcv. Oil seals will be less effective also w/out pcv.
I just asked Aaron at Metco to make me some breathers with deflectors. He's checking into it. I want to run a Metco on the back of the driver's side valve cover but without a deflector I might get some oil on the firewall when racing.
Joined: May 2004
Posts: 1,593
Likes: 267
From: Halfway back on the Highway to Hell...again!
Some type of vaccuum is needed to pull pressure from the crankcase. if you let it breath free at normal driving, everything will be fine. When you get into rpms above 5k, you need something to pull the pressure out. Serious racers use an evac system that runs to the header collector. This "kit" will have a valve to keep exhaust from going the wrong way. The idea of an evac is to keep any oil and oily combustibles out of the intake and A/F mix, i.e pcv valve system. It's not $$ and easy to do if you can mig...oh and have full length headers.
Oh and if you use this on the street, you will use much oil. but there are kits to open and close they system. Sort of like the electric cutout deal.
Oh and if you use this on the street, you will use much oil. but there are kits to open and close they system. Sort of like the electric cutout deal.
Originally Posted by Pro Stock John
I just asked Aaron at Metco to make me some breathers with deflectors. He's checking into it. I want to run a Metco on the back of the driver's side valve cover but without a deflector I might get some oil on the firewall when racing.
I run a metco on the passenger VC and put a small breather where the PCV valve used to be. Just clamped it to the hard plastic hose. The hose till hooks into both valve covers. No oil from that small breather at all. There is a bit on the metco but not bad.
Brad
Brad
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From: new england
Originally Posted by rally2247
So, what are some long term effects of having the PCV hose connected to the driver's side valve cover partially torn? I'm asking this because when I took off my valve cover the other day I noticed the PCV hose was torned a bit.
Originally Posted by LS1derfull
Sorry about the late response but a torn pcv hose would be a direct vacuum leak, causing pcm to richen a/f mixture. this will cause bad mileage and rougher running motor.
You can experiment by sucking on the vacuum end or blowing on the opposite end of a PCV valve, No matter how hard you suck or blow only a certain amount of air will pass through the valve if you have it oriented in the correct direction of flow.
Also at levels of low engine vacuum, like WOT, the PCV is not doing much of anything. The PCV only works it's best at high engine vacuum. It's basically designed for high mileage street duty engines. Mostly race engines don't need a factory style PCV. The vacuum pump or header evac system is cool for race only engines.
Double duty...run the PCV on your daily commuting/street slogging and on race day plug the PCV and run some breathers or just run a catch. Catch cans also work well to keep oil out of the combustion chambers.
BTW, I have an occasional daily driver/slash track car. I run a plugged off PCV system and a Metco on the oil filler cap and and a smaller breather in the back hole on the drivers side valve cover. I also change my oil frequently.
I may get a catch can and run that with the dual breathers.
Last edited by Dustin Butts; Sep 11, 2004 at 06:36 PM.
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Joined: Dec 2001
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From: new england
Originally Posted by Dustin Butts
Sorry, I'm not trying to be a an a$$ or a know-it-all, but....if the PCV hose is torn behind the PCV valve(ie on the opposite side of the direct vacuum source) then all you'll be doing is sucking dirt into your engine(instead of crankcase gases) through the tear in the hose. The PCV valve is just that...a valve that controls vacuum to a certain amount. In other words the engine is already tuned for this controlled vacuum leak on the post-suction side of the valve.
You can experiment by sucking on the vacuum end or blowing on the opposite end of a PCV valve, No matter how hard you suck or blow only a certain amount of air will pass through the valve if you have it oriented in the correct direction of flow.
Also at levels of low engine vacuum, like WOT, the PCV is not doing much of anything. The PCV only works it's best at high engine vacuum. It's basically designed for high mileage street duty engines. Mostly race engines don't need a factory style PCV. The vacuum pump or header evac system is cool for race only engines.
Double duty...run the PCV on your daily commuting/street slogging and on race day plug the PCV and run some breathers or just run a catch. Catch cans also work well to keep oil out of the combustion chambers.
BTW, I have an occasional daily driver/slash track car. I run a plugged off PCV system and a Metco on the oil filler cap and and a smaller breather in the back hole on the drivers side valve cover. I also change my oil frequently.
I may get a catch can and run that with the dual breathers.
You can experiment by sucking on the vacuum end or blowing on the opposite end of a PCV valve, No matter how hard you suck or blow only a certain amount of air will pass through the valve if you have it oriented in the correct direction of flow.
Also at levels of low engine vacuum, like WOT, the PCV is not doing much of anything. The PCV only works it's best at high engine vacuum. It's basically designed for high mileage street duty engines. Mostly race engines don't need a factory style PCV. The vacuum pump or header evac system is cool for race only engines.
Double duty...run the PCV on your daily commuting/street slogging and on race day plug the PCV and run some breathers or just run a catch. Catch cans also work well to keep oil out of the combustion chambers.
BTW, I have an occasional daily driver/slash track car. I run a plugged off PCV system and a Metco on the oil filler cap and and a smaller breather in the back hole on the drivers side valve cover. I also change my oil frequently.
I may get a catch can and run that with the dual breathers.
