pcv or evacuation system for a weber set up

[paul cass]

Hey guys
The catch can came in last week just in time for me to install before our annual Cobra event in San Marcos. I got it installed and as for as I can tell it seems to be working perfectly. If one of you can tell me how to post pics I'll show you what I came up with. Came out pretty good I think.
Paul

[paul cass]

Hey guys. Here is a pic of the catch can mounted for my pcv evacuation system.

[Gaz64]

Hi Paul,

A few things that interest me here from your photo.

Your passenger side hose won't flow much with a PCV valve fitted at the valve cover, so then the bulk of blowby will try to pass through your drivers side hose.

If you study some race cars, larger breather hoses allow slower air flow, and a chance for any oil to fall out of suspension, instead of the high speed jet of air/oil associated with hoses too small.

There's no such thing as hoses too large, of course nobody runs 3 inch breather hoses , but two AN10 hoses, or a single AN12 hose are my recommendation as minimum for V8 over 300 cubes.

One day, I'll post a drawing of my closed breather system that uses a Moroso Vacuum Pump Air/oil separator that self drains to the valve cover, a pcv valve that breathes from the tank after the filter medium, and no oil in any hose after the separator. My tank is mounted high at the back of the engine bay, all hoses run "uphill" from the engine, which gives little chance for any oil to get to the separator, but if it does, it self drains via a 6AN to the valve cover.

Allowing the engine to breath freely when under load, lessens the chances of crankcase pressure related oil leaks as well.

On IDF Webers, the Emulsion tube stack (Extension/Air Corrector/Emulsion tube/Main jet) and the Idle Air inlet are exposed to outside air, as in your installation.

On IDA Webers, the Emulsion tube stack and the Idle jet Holder are covered with a screen. DCOE Webers are also covered with the "Mousehat".

They can afford to run open velocity stacks, or screen filters, one per barrel, whereas on the IDF, the engine is inhaling unfiltered air via the air corrector, albeit in small quantities.

The Idle air is particularly susceptible since the inlet is low in the airhorn.

CB Performance offers a fix called the "jet doctor".

I personally would have a K&N oval filter per carb, so all of the air inlets receive filtered air.

I hope I haven't been too critical here, and you may take some advice onboard.

Gary