The pcv does have a restriction in it, an orifice, so it doesn't have "full vacuum" all the time and obviously under WOT the vacuum is at its lowest but under normal "cruise" conditions its quite high and removes all those impurities from the oil. Thats why I said if its track only then go for it, or if its a street car do it for track use only. Thats the best of both worlds. Its a proven fact that the pcv does keep the oil cleaner and reduces sludge and other crap from accumulating in the engine.

In my GN, the pcv made a huge difference in the condition of the oil but because I ran aftermarket aluminum heads I couldn't use the stock pcv setup without pulling so much oil I fouled my plugs literally within minutes. So I spent a great deal of time researching and experimenting with various pcv systems. I used clear tubing whenever possible, for observation purposes. You should have seen the difference between having a pcv and not having one. The moisture would have no way out but through the breathers (I had more breathers than you can shake a stick at too) but without the help of the pcv the oil got a gassy smell much faster and the underside of my valve covers and intake manifold got that nasty white foamy crap on them.

Oil must reach a certain temperature to boil off these contaminates, no matter what. Thats why cars used for short trips only tend to have dirtier oil. But relying on the breather only isn't as good as having something to suck out those fumes.

If a guy wanted to spend the time, and it wouldn't take much, you could probably make a system using valves and some breathers and hoses to make a "switchable" system, to where you could just turn a valve handle to have the pcv operational or turn it the other way to go to the open breather setup.

 

hey just a thought. What if you installed a breather but kept the pcv system? Could that be the best of both worlds or would that screw something up?

 

That has been discussed before. Don't do it. You will then have a vaccum leak because air is being ingested that is not accounted for through the MAF.

 

Instead of plugging that grommet in the drivers side valve cover, why not strap a breather to it? Then you have the both breathers problem solved.

Also...would it hurt to leave the fresh air line running from the passenger side valve cover to the throttle body installed?

thanks a lot

 

Look at the post above yours.

 

Ok.
So what about putting a breather on the grommet that is on the rear of the drivers side valve cover?

 

if you read the original post thats what i did.

 

hmm...I read through it...I must have missed it.

thanks

 

Thanks SUX2BU for the write up , car runs great with no problems .

 

what air is being ingested? that the mass air sensor did not account for?

if you just leave your PCV system alone and install a breather on the passenger side valve cover how can this hurt anything?
It will only releave more crankcase pressure build up espicaily at WOT, NO???
it may even help a bit with the oil geting sucked into the intake?

 

This has been explained many many many times.
Your PCV uses a slight vacum to pull out crankcase pressure. when there isn't that much crankcase pressure it pulls air from your TB (after it has already been thru the MAF), into your valvecover, thru your PCV valve and then in to your intake.
If you just add a breather it will pull unmetered air (has not been thru the MAF) thru the breather, thru the PCV valve and into the intake.

 

OK got it SUX2BU,, thank you

I see what you mean now, the LS1 uses a unique PCV system, and i just figured how it realy works,
OK so if we want to install a breather , we have to remove the PCV system so unmetered air does ont get sucked into the breather then through the PCV valve and finaly make its way into the intake.
The motor , the computer would not know where that extra air is comming from.

Ok well i would realy like to remove the PCV system to prevent any hot oil and oil vaper from getting into my intake, although i just cheched my intake and a 25,000 miles it looks very clean, i could feel with my finger a very slight slickness but no oil build up at all that i could see.
So how do you feel about what some others are saying? about if we run breathers and get rid of the PCV system that condensation would build up and gasses, and would contaminate our oil?

 

also what about that old trick everyone was doing a while ago, installing a small fuel filter in the PCV valve line, and replacing it at every oil change?
I would think on a LS1 like mine that does not use any oil that the filter would block any small amount of oil from getting in the intake.
let me know if anyone is still doing this and how it is working out

 

My oil looks normal when ever i change it.
I used to use the air/water seperator and it worked ok but still got some oil in my intake.

 

Hey prostock....I see you still have the fresh air line going to your throttle body.

I thought this should be removed?

 

well?

 

Any components of the pcv that allows air into the engine should be removed or else you will have a vaccum leak with a breather.

 

So the fresh air line to the TB can stay

 

see my above post

 

a few other people listed the real, downsides, but i'll list some again anyway.

first you need to know, WHY is the PCV system there??

its NOT for evaporative emissions.. its for the engines oil change life.

the byproducts of combustion, mostly gasses, do get into the crankcase. some of these are acidic, some is water, ect.. the PCV systems job is to remove these crankcase vapors and replace them with clean, fresh air. it is to provide a constant flow of fresh air.. NOT to create a vacuum. yes, it does have a SECONDARY job as a vent, letting off pressure, but the PCV systems primary job is to provide fresh clean air for the crankcase

what happens if the PCV system is removed?
well, assuming you have a breather, you will not have any excess pressure in the crankcase.. thats the route most people take. however, all of the combustion by-products, will make their way into your oil, and slowly increase in there..
your oil should be changed on a VERY VERY frequent basis... otherwise water vapor will condense in it.. and the oil will become slightly acidic and eat at bearings...

why cant i just run breathers, race motors do it??

race cars get their oil changed very frequently. they are inspected and gone over on a very regular basis... if you think about it, this is the same as you getting out and going over your motor ever 5mins of driving... road racers, sports car racing, ect DO run a Positive crankcase vent system... either a conventional one, or a vacuum pump.. its mostly drag racers with the breathers only. and you now know why.



in the 50s, there used to be a hole in the back of the block to act as a vent.... in the early 60s someone invented this neat little one way small orifice valve they called a PCV valve... all of a sudden, oil change intervals were measured in 1000s of miles instead of hundreds... thats how long ago this was discovered, and how long its been around... this basic PCV system exists on every car for the last ~40 years, import, domestic, or whatever.. most motorcycles and even larger engine tools have a PCV system.. and while they vary in orifice size in the valve, they all operate the same basic way.


do NOT remove your PCV valve in a street car... instead, run a LS6 style PCV valley cover... run a air/oil separator.... or just disconnect it at the track, but run with it everyday otherwise...