Farmall ?

Can anyone tell me what the valve is for on the exhaust manifold on a Farmall H? Its right about in line with the hood, on the left side of the tractor. Mine seems to be frozen. I just would like to know what its for, and I dont see any info for it in my manuals. Thanks J

Don"t quote me on this, but I believe it closed when the engine was cold in order for a faster warmup. Most everyone I"ve seen was rusted up.

Sounds an awfully lot like the remnant of the heater for a dual-fuel engine. It was started on gas from a small tank and switched over to distillate once it warmed up some. Distillate was a pretty low-grade fuel, and the purpose of the shroud and the valve was to trap heat from the crankcase and exhaust side of the manifold, to warm the intake side of the manifold to give the distillate a fighting chance to burn well in cold weather. When actually functioning, you had a choice of several adjustments, with as close to regular, unimpeded convection through the shroud being the setting for warm weather, and as near closed as it would go for operating in the cold. I could only speculate whether the effect was to improve vaporization or to reduce condensation of the carbureted fuel as it was drawn up thorugh the manifold or some combination of the two, but the net effects were a better burn and less washdown of fuel into the crankcase. Distillate ran cold, so you'll often find radiator shutters, too, on tractors with distillate/dual-fuel motors, to raise the coolant/operating temp of the entire motor.

Now, after all that . . . if your valve is a simple plug, or looks like a simple plugged up check valve, or with the remnants of a small valve on it, it may have been a hookup for a vacuum line that could be used to operate a milking system.

If you are talking about the lever in the manifold it was for running on karosene. kept the tractor hotter so it would burn better. The manifold should look like the one in the picture. If your running on gas you keep it open. Mine on this H is frozen up open.

Yes, I seem to think it looked like you could slide a small hose on it, and it was a brass colored handel too. I thought maybe it was to inflate a tire, like on those older Zetor tractors lol ha ha! Thanks J

Hmmmm. I suppose somebody could have adapted something else up, but the tire inflators that were sold with the Farmalls used a spark plug fitting rather than going to the manifold. Is this thing on yours on the exhaust or the intake side?

On the exhaust manifold. Just above the carb.

That is the vaccuum port. Could be used for powering milking machines and such. Usually there is just a pipe plug in that hole.

That's actually on the INTAKE manifold. You get vacuum on the intake, pressure on the exhaust.

Yeah, I guess your right, I just looked at it and it is strange! The carb in mounted on the same manifold as the exhaust, I mean it all looks like one piece. ...j

Jay: I'm with Rusty, if this is on the intake side and about 1/2" male port. Many tractors were fitted with this vacume device to milk the cows when power was off. It worked well but would only run one milker. Didn't seem to have enough vacume for two. I think ours could have been better with a reserve tank. Cows and dad's were a bit more receiptive to hand milking in those days as well.

Yup. A lot of older engines are that way and all of the letter series Farmalls, and many tractors of that era. If you're not used to seeing them, or more accustomed to them being separate, it does take a little studyin' to figure out which branch does what, but the clue is that there is only one manifold, and it is fitted for both the carb and the exhaust pipe.