I've searched through a ton of old threads, and I haven't been satisfied with an answer yet. I have 15psi of boost, and would prefer to disconnect the factory PCV line to the throttle body and replace it with a breather on the valve cover and a plug on the throttle body. I will be running a speed density tune, and want to make sure I'm not screwing myself up. Has anybody done this or have any reasons not to disconnect the factory PCV? Thanks for the help!

Ben

 

Breathers will work, but the reason you shouldn't disable the PCV system is because it draws fresh air through the crankcase to flush out acidic combustion gasses. Your oil will break down much, much faster w/o the system due to hydrocarbons in the blowby gasses.

 

Excellent. Thanks Mike!

 

I believe hes talking about the breather line on the pass. v. cover, NOT the pcv. The pcv valve is in the driver side of the intake manifold and looped to another nipple right next to it, not the t.b. This needs to be disconnected from the t.b. or you'll pump the crankcase full of pressure under boost. I turned that vent line into a suck line through a catch can and on to the suck side of the s/c. I then later added another one to the driver v. cover and tee'd them together. Seems to work pretty good now that the rings seem to have seated.

 

I must have been asleep still, because you're right, it's not the PCV I'm talking about. I'm going to disconnect the breather line to the passenger vavle cover and replace it with a baffled breather. I was going to do both valve covers, but it seems most people get away with the one. I might add one to the drivers side before I hit the track, only having a single breather just makes me nervous.

 

i run a breather i the drivers side intake and one on the passanger valve cover.

 

I tried alot of the above solutions. Not happy with any of the performance. Ended up with this.
http://s306.photobucket.com/albums/n...p%204th%20gen/
This helped cylinder pressure way above my expectations, and, solved all oil leaks (front and rear main seal). It's a happy motor and revs fast. It was a custom build, and, was my winter project 3 years ago. Some may not be up to it since I had to move the rad forward and do fabrication.
App... 97ss 383_D1/ MM6 AFR heads and all the other stuff.
I like all the added space up front.
All the best.
B.

 

Please note that a valve cover breather system is not an evacuation system. If you want to pull vacuum in the crankcase to evac combustion by-product and increase ring seal, you can use the exhaust or better yet a vacuum pump.

Scott

 

Scott, your still alive!

 

Hey Jon, haha. Car has been on the back burner so I don't get to the site much as of late. Hopefully I'll be able to commit to the last little things the car needs to get it running correctly during winter/spring.

In regards to exhaust evac. I think it does work to some degree and plan to quantify with a vacuum gage I have to measure what's happening in the downpipe. If anyone happens to have measured data on this already it would be interesting to see.

Thanks,

 

i have everything disconnected and have a open element valve cover breather also I have a electric vacuum pump I switch on when I am at idle to clear out any blow by it is also set up on a hobbs switch that come on at 6 psi ... this helps to prevent any leaks and to prevent the intake gaskets from leaking in the back etc

 

you can also run a breather on the pass side and take the pvc line from the intake and run it to the intake side of the blower..

 

I'm a little confused by this thread. Your D1SC kit should have include provisions to run the passengers' side crankcase vent to the suction of the blower. Leaving on the TB will ENSURE the crankcase is pressurized with boost, which is a bad thing.

Beyond that, I found that at 15+ psi boost, the single vent wasn't enough. I kept pushing oil out around the dipstick tube. I finally installed a similar vent on the driver's side (retaining the PCV) and ran it to the suction of the turbo and didn't have any more problems.

 

Here's my setup after careful consideration:

Running two passenger side valve covers with Metco oil fill adapters with -10 an fittings on them. Running the -10 line forward to Allstar vented breather tanks located on the front impact bar. Running the PCV Valve to a short inlet pipe located straight on the turbo. Should keep from pressurizing the crankcase with this setup.......

 

Well it seems like there is no specific answer to this topic so here goes my question. I'm running 17psi through a 383 and I have narrowed the crankcase ventalation down to two systems. First one involves two welded an bungs on each valve cover and braided stainless lines running to catch cans, similar to the ones in the picture above. The second system would involve the brainded stainless lines going into a moroso oil seperator http://www.jegs.com/i/Moroso/710/85471/10002/-1 then a line going from the seperator to the suction side of the supercharger. The pcv valve is already looped on the intake manifold. Any help would be greatly appreciated.