intake air through oil?

does all the intake air actually get pulled through the oil in the air cleaner?

yes it does.

No. The intake air is forced to make a very sharp "U-turn" just above the surface of the oil. Dirt particles in the air can't make the turn, and go straight ahead into the oil, which keeps them.

On my H the air inlet pipe extends down into the oil in the cup of the air cleaner about 3/4".

Greg

(quoted from post at 21:44:35 12/24/10) does all the intake air actually get pulled through the oil in the air cleaner?

Click to expand...

Yes and no, kinda.

The oil level is above the bottom of the inlet pipe so to start with the air is drawn through the oil. As more air is drawn through the oil, some of the oil is carried up into the mesh in the filter until there is a balance on the oil being drawn into the mesh and what drains back down. The level of oil in the reservoir cup will vary depending upon the viscosity of the oil and the volume of air being drawn through the filter. The dust is actually removed from the air by the oil film in the mesh and is carried back to the reservoir with the oil as it drains back down.

maybe we can put it this way, all the air that the engine requires for combustion is drawn thru the oil bath, there are no other sources of intake air and if there is another source you have a problem, that should be sealed properly.

the reason I asked is because I just bought a 300 u this fall and am not very familiar with it.

From my perspective, there are a number of related things involved here.

I changed the engine oil a few weeks ago because I didn't know when it had been changed before, and I thought it would be good to make sure it had as light an oil as possible in it for cold weather starting.

I had posted a question here about 10w 30 oil.

It had always started fine when the weather was mild but sure enough it wouldn't start when it turned cold.... battery wouldn't crank it very long.

I also posted about it seeming that it did not fire until AFTER I quit cranking.

At one point I posted about the 12 v conversion that had been done to it.

Then I thought about the oil in the air filter... I had no idea what that was like... I thought, "well maybe it's thick and can't suck air through it properly", so I changed it also...

It had some ice frozen in the bottom... the oil was pretty thick and had a fair amount of gook and large particles in it.

Turned out, I bought a battery and several questions were answered all at once... the engine turned over well... It fired [b:b38920b0df]during[/b:b38920b0df] the cranking... and it started up.

but I still didn't know about the air being drawn through the oil.

The oil is all below the filter.. there is a cup shaped thing welded into the bottom of the oil cup but it doesn't seem to be made to draw the air through the oil... it does seem like it might be shaped to cause the oil to be pulled and splashed out of the cup, by the air, and sort of thrown about amongst the air. sort of similar to a "lawn sprinkler" of oil..... and there is a little hole in the cup shaped thing to allow it to fill back up with oil but certainly not enough to draw any useful quantity of air through it.

Here you go. This article expliand how it works.

http://www.ehow.com/how-does_5591461_oil-bath-air-breather-works.html

The ehow article is a little too simplified for a typical tractor filter. If you follow the next link you get a more complete explanation (the second illustration).
http://vintagetractorengineer.com/2009/01/oil-bath-air-cleaners-for-tractors/

thanks folks ....very good stuff. It's nice to know how stuff works... now I only gotta figure out the rest of the tractor :lol: