Oil bath air cleaner. has this rectangle flapper that has a counter balance wieght on it. Seems from racing yesterday it was blocking off the PCV vent to the intake. Oil seemed to still find the path of least resistance and leaked out of the hose connected to the PCV and the cork gasket between the filler/breather box and case What a mess.

It 's to keep weak mice out of your intake. The stronger ones just push through.

or

It's to keep the good air in and not let the bad air out

or

It creates turbulence in the incoming air

or

It's part of the archaic warm air system fitted to cars in very cold climates.

or

???????????????

bingo ...

Ahh Andy, I liked the other answers better. Since you made me fess up, I'll explain the principle

On start up, the air velocity would be low, causing the flapper to stay in a closed position, thereby drawing warm air off the HEs. As the throttle is opened, the velocity of cold air overcomes the counterweight and restricts the flow of warm air.

Then figuring in the density of warm air vs cold air..............,

What do I win?

You win another one of what ever you are smoking. Well since it made a mess it has to go. At least till I make a few redline runs to see what happens now. Pretty tough to do on the street. Matbe just leave it in 2nd all the way to work. Rise and shine all ya'll. BBWWWHHHAAAAAAAAA

On some cars, there was an elbow/j-tube coming off the HEs through the tin for that purpose.

You can also check page 41 of your Haynes Manual (if you have one).

I think I will have another

Well while you are at it give me one Ya got a haynes and factory set of books. HMM maybe I should read it again????? Is it me or do the factory manuals jump all over the place concerning the obscure little things I can't figure for myself.

Didn't drive today as I decided to do a valve check and brake vent clearance without burning out of my arms. Got to get up under and clean oil soaked road grime too.

Joe, if it's for heat take it out, you got enough heat in MS already....

Yea tell me about it. Never did stop sweating tonight. Just got the car put back in the garage. Set venting clearance rear brakes. Q: Why does this always seems to take so long. ans: Because it is hot never seen two car with same size inner screw. Can't see it so I ended up taking caliper off to get it right so I didn't strip anything. Actually these were all screwed up one pad loose one pad tight and dragging. same on the other side. Anyway it is time to watch hot chicks play beach volley ball.. Yes the USA girls are HOT. No need to vote that one