Crankcase evac on LT1...advice needed to wrap up

dhirocz

Member
Im about to wrap up this wrenchfest on the car and one of the last things im about to embark on is the crankcase evac.

I already tig welded the tubes into my exhaust. Im running 3" dual stainless with longtubes. Welded them in 8" behind the 02 sensors.

My plan is to run two catchcans (made from modified old a/c dryers) that hook up to the exhaust. From there, one side will hook up to the drivers front valvecover, and the other to an elbow at the factory PCV location which vents under the intake baffle.

Im considering using my unused 5/8 connection on my airbox, running through a checkvalve and into the passenger rear vent in the valvecover to supply filtered air in(so I dont suck air into the catchcans during acceleration), possibly through a regulator if needed. However, this is my first attempt at a crankcase evac system, and there is very little info out there on it.

Do I need fresh air in or no?
Are there higher quality (or more sensitive) checkvalves available other than mr gasket?
Should I keep both cans seperate or just run a large single?

Engine is a cammed 350, but the going thing Ive noticed is the PCV is rather inadequate...works fine at lower RPM as designed. Im trying to sort it out before I drop in the 427 in the next year or so.

I do plan on running a vacuum gauge on the crankcase.
 
these links should help
pcv_system_extracting_moisture.jpg

http://garage.grumpysperformance.com/index.php?threads/catch-can-related-info.4636/#post-12610

http://garage.grumpysperformance.com/index.php?threads/crank-case-blow-bye-and-related-info.16790/

viewtopic.php?f=80&t=1219&p=2584#p2584

viewtopic.php?f=52&t=2005&p=5328&hilit=positive+crankcase#p5328

viewtopic.php?f=87&t=4636&p=12451#p12451

http://garage.grumpysperformance.co...breather-hole-in-valve-covers.2005/#post-5328


viewtopic.php?f=54&t=694&p=965&hilit=positive+crankcase#p965

viewtopic.php?f=54&t=2207&p=12639&hilit=+vacuum+crankcase+pump#p12639

http://auto.howstuffworks.com/positive-crankcase-ventilation-system.htm

viewtopic.php?f=53&t=4630&p=39780&hilit=+maximize+seal#p39780

viewtopic.php?f=54&t=10646&p=45917&hilit=seal+ring#p45917

viewtopic.php?f=53&t=509

viewtopic.php?f=53&t=5454
 
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Ok, so I ginally got the car fired up and running using the 0411 PCM/coilpacks.

I still have a few things to iron out, this being one of them. Still can't find a few answers.

Are the flats at the end of the vacuum tube best run facing rearward, or parallel to the exhaust flow?

I installed one on each bank, 8" behind the oxygen sensors. I will be going out and testing each side for vacuum strength this weekend. Im wondering if maybe that was too far away, but I was trying to make sure I didnt oil foul the sensors.

Im planning on running a catch can. How did you guys run yours for best results? Im still undecided on how to plumb it up, or if I even should run an air inlet or not.

This is my first go at running this, so Im trying to have a knowledge base to work with before I start with trial and error.
 
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