Need input on crankcase evacuation remedies

[Ron Sutton]

I love the Arrington race catchcan V2. It is simply the best design. The only drawback is cost.

We offer a "good one" from Moroso for about half ... at the bottom of this page HERE.

[SSLance]

Alright, 90% of this project is installed and operational. All I'm waiting for is the Pass side breather I ordered to show up so I can plumb it to the bottom of the air cleaner, for now I've just got the old open breather on that side.

Here's the can hanging off the airbox right behind the headlight.



The 3/8s lines running from the can to the now gutted PCV breather on the valve cover and manifold vacuum port on bottom of carb.



And I can even see the site glass by looking under the core support by the charcoal canister...




This setup is pretty sweet, here are a few pictures of the top of the can, inside the breather top and even inside the recirc top for you to see as well.







There is a check disc inside both the open breather and the recirc top that lets air flow out if needed but when vacuum is put on the can it seals the top off.









If any questions just ask away, I think I now have a handle on how all this works and can't wait to try it out under sustained WOT applications...

Thanks for all the help with this guys...sure hope it cures a few ills I had last season.

[cluxford]

Interesting thread thanks for sharing. I run two catch cans, with only breathers and no connection back to carb so it just escapes to atmosphere. My car stinks so bad the family won't go in it. I am re-thinkng the set up to get fumes down and family in

[SSLance]

I fixed the pass side breather last night. I thought I'd try another PCV over there gutted and plumbed to the air cleaner but it was too difficult to restrict the flow on...so I looked at the open breather I had there originally and came up with an idea.



I cut a piece of rubber gasket material with a piece of copper pipe and poked a small hole in it with a leather punch...and put it in the center of the breather making it just about as hard to suck air through as the Mighty Mouse PCV.





This should give the system the intake restriction it needs to make the MM can setup work as designed. It's all on the car and ready to be tested...I'll update once I get some miles on it.

[Vegas69]

I ran -12's from the top of both valve covers to separate catch cans. I ran the snot out of mine everywhere and they worked very well. They would smoke a little until the moisture burned off. I don't recall any messes. I would drain them once in a while. Never more than an ounce or two.

Why suck the vapors back in the engine? I get it on a street car where you want to go 3000 miles between oil changes.

[dontlifttoshift]

So, to make sure I have the flow path right.

Fresh air enters the passenger side valve cover through a small hole. Then it flows through the crankcase to the drivers side valve cover where it is connected to the air oil separator with a 3/8" hose and mounted below the height of the valve cover and then connected to the intake or carb baseplate with another 3/8" hose. Right?

In theory, the crankcase will have negative pressure at idle and cruise but I just don't see one 3/8" hose being enough ventilation at wfo. Crankcase pressure will go positive and it will try to push through the AOS, taking oil with it, and when that's not enough, gaskets will start to leak.

At least that's the way it looks from 500 miles away. I hope it works for you but I think you will want a 5/8" inlet/outlet on the passenger side.

[will69camaro]

David (MightyMouse) is a wealth of knowledge on this. I spoke with him at length before setting up my car.

Have his PCV can on mine with:
-10 from behind air filter to DS valve cover (clean air)
-12 from passenger cover to catch can (dirty air to catch can)
-6 from can to intake through a PCV (clean air return)

Very happy with the look and so far so good for the performance of it.


You can see the -10 on the far side in front of the brake reservoirs, and the -12/can/etc on the passenger side firewall.

[SSLance]

Originally Posted by dontlifttoshift

So, to make sure I have the flow path right.

Fresh air enters the passenger side valve cover through a small hole. Then it flows through the crankcase to the drivers side valve cover where it is connected to the air oil separator with a 3/8" hose and mounted below the height of the valve cover and then connected to the intake or carb baseplate with another 3/8" hose. Right?

In theory, the crankcase will have negative pressure at idle and cruise but I just don't see one 3/8" hose being enough ventilation at wfo. Crankcase pressure will go positive and it will try to push through the AOS, taking oil with it, and when that's not enough, gaskets will start to leak.

At least that's the way it looks from 500 miles away. I hope it works for you but I think you will want a 5/8" inlet/outlet on the passenger side.

You are close except for one part. Should the blow by be more than the 3/8s line can handle from the driver side VC to can, it will then try to exit via the pass side breather as well. If I see sign of oil coming out the pass side breather, I'll up the size of the line from the driver side breather to the can. If you up the size on the pass side, that just makes an easy exit for the blow by air to go that way, which is not what you want.

David at Mighty Mouse says a 3/8s line is good for up to 600 HP generally, but every case is different depending on engine and other variables.

The main difference with his setup is his check valve in the can which takes the place of most PCV valves. It will NOT close off under WOT like most PCV do. This lets the manifold vacuum keep sucking on the crank case even under WOT and that keeps the air flowing in the pass side, out the driver side and the excess that doesn't make it out the check valve to the carb goes up out the breather on top of the can.