VGLNTE1

I have a catch can i use that about 3"x3" thats 15" long. Huge. I have one line coming from the valley (dirty) that goes to the bottom of the can. I have a hose on top of the can going to the intake. Still suck oil through into the intake. How do you guys combat this when your flogging your car for such long periods?

travisnd

You have it hooked up backwards. The pressure source should go into the top of the can so that it is forced down through the mesh. This will remove the oil from suspension and cause it to drop down into the can. The pressure then flows out of the side (bottom port). I have two cans.... one on the normal PCV circuit from the valley to the manifold and one on the fresh air feed line from the passenger side valve cover to the TB. This line normally lets fresh air into the valve cover to balance the PCV system. However, during extended high RPM running the oil can get hung up in the head and get forced the opposite direction into the TB.

VGLNTE1

Mine dosnt have any mesh or filter. Its just a massive can. Why would you run the dirty side on the top where the oil would run down to the clean hose? I have a 416 cube motor and the crank case preasure is nuts. I figured the oil vapor would never get all the way up the can...:-/

Screamin Z

Get a vented catch can. Plug the hole in the intake. Canton makes a good unit.

VGLNTE1

vented means unmetered air. thats a no no.

travisnd

Then your can is worthless. You need some material to get the oil vapor out of suspension. The oil won't "fall" into the lower hose. The proper way to plumb a can is pressure source into the top and then out the side.

Nothing wrong with a vented can either. Yes you'll draw some unmetered air into the engine through the filter when in vacuum, but it's not going into the combustion chamber. The downside of a vented can is that they can make a big mess.

People usually take on of two routes:

1. Plumb two cans into the OEM circuits like I have.

2. Cap the fresh air feed line from the VC to the TB and the PCV inlet port on the manifold, and then run a vented can on the PCV pressure lines. The other option would be to cap all OEM ports and a line from each valve cover to a vented can back on the firewall.

VGLNTE1

i see what your saying now. I am trying to incorporate a filter into mine. I had mine ran like you have before and i still sucked oil through it. I ran a vented one before and about caught the car on fire with all the oil spewing all over the headers. I need to keep it a closed system. I just bought a air oil separator to use between the line going to the intake. Hopefully that helps and my big can still grabs the excess, which it does really well now, but the oil in the vapors still get in.

travisnd

Yeah oil on the headers is a big no-no. Maybe sell the can you have now and get ones that have something in them to separate the oil out. Big open cans really don't do anything.

VGLNTE1

Im trying to find a large one that actually has a system in it that will work for me.

RX-Ben

http://www.saikoumichi.com/Stage1_LS1_page.html

Or put a section of beaded pull chain in the typical corvette catch can as shown in Brian's pics.

It is important that each of the lines running from the TB go to the side fittings on the cans. Otherwise you will blow out valve cover cover gaskets and oil down the engine bay.

travisnd

That's a really nice can. If you look at his schematic the way the ports are engineered looks like the optimal design. You'll only blow out your valve cover gasket if your run your pressure line to the valve cover inlet port.

travisnd

For reference here's the guts of the cans I have....

JDIllon

Here is a set up that I'm running and it works great! No oil back to the engine. 2 vented catch cans, one from the sump and one from the valley cover, both intake holes plugged. These are the Canton catch cans. JD
[IMG][/IMG]
[IMG][/IMG]

VGLNTE1

If you are running just a vented set up, i think your not pulling vaccum and leaving the contaminents in the motor and not pulling the oil back down from the cylinders. Ive tried that method

VGLNTE1

yup, had that one. Still sucked oil through it

travisnd

They don't work 100%, oil is going to get past. If you had the lines hooked up incorrectly then you reduce the effectiveness of the can to begin with. If the engine is pushing so much oil that you're filling up cans then something is amiss with your bottom-end.

Track cars don't need to pull vacuum on the crank case. Being run at high RPMs all the time will force the combustion byproducts out. Street cars that see more time at idle/cruise need a proper vacuum assisted PCV system for the reasons you state.

VGLNTE1

i dont come close to filling it up. About 1/2" to 3/4 of an inch after 3 hours of beating on the car. Its just the velocity of the presure that gets by. i want 0% to get back in. Maybe if i stuff 45 scotch bright pads into my huge catch can.

Bad Karma

If you don't want any then I'd say go vented set up or route the crankcase into the exhaust.

VGLNTE1

Im not a fan of vented, and the last thing I want is to have burned oil out the tailpipes and all over the *** of the car.

i will get it work....

Rob's 73

vent it while you are at the track. You are not pulling a vacuum at WOT anyway.