Barney Oldfield and the Allis Chalmers "999"

"He made the runs in 1933, at the age of 55 and well after he’d raced his last, so the tractor runs were just publicity stunts, complete with the number 999 painted on the hood – a blatant reminder of Oldfield’s past racing glory."

Very nice pic. That tractor even looks like it's leaning forward!

Can you imagine runnin' 60 some MPH on one of those tractors...let alone one of todays tractors??

Well, actually, the rear tires were probably the safest thing about the whole stunt, if I'm not mistaken, they were aircraft tires. But, still bigger baxx's than I got!

The lean forward comes from a focal plane slit shutter. Traveled down over the film, or up across the upright image. The high speed slit was only a small fraction of the frame high, probably a Leica 35mm. The tractor traveled that far as the slit moved.

As for tire balance, the fronts would have been a more serious problem because they spun a lot faster, as fast as a car and most cars in that era didn't go 68 mph. Even if they could the roads weren't good for that speed.

I wonder what they did besides stiffen the governor spring to get that speed. A custom set of final drives? And a custom ring and pinion. The farm speed of that tractor probably was 12 or 15 tops in road gear for 1800 rpm at the engine. A balanced enging would double that maybe. Looks to me that the rear tires are about 11-24. I don't see a drop box, so that would take out a lot of the reduction going direct to the rims. Looks like about 125" circumference or 506 revolutions per mile. At 60 that would be 506 rpm at the axle. If road gear in the transmission was straight through that would mean about a 6:1 drive ratio for 3100 rpm engine speed, or 575 rpm,  3450 rpm for 6:1 final dirve ratio. Those tires at 15 mph, would be turning 126 rpm, with an engine speed of 1800 (fast even for that era) giving a total drive ratio of about 14:1. I'm presuming the top gear in the transmission is straight through and that all the reduction is in the ring and pinion and the axle end drop boxes. I don't see getting all that top speed from running the engine speed up to 8200 rpm. Unless it was an Offenhauser conversion to a model A Ford engine or something like that.

Gerald J.

So 4800 rpm at 60 mph, 5440 at 68. Possible with a balanced crankshaft and no governor. Might wish for a bigger bore in the carburetor for better flow.

Gerald J.

Running at 4.5 times the rpm, the air flow through the carburetor is going to want to be at least that much more than stock. And that "33 hp" engine is going to produce a lot more power than nameplate. There are many variables that we don't know about the engine details that make any computation of actual power a WAG. Things like while building a balanced crank to keep it from flying apart, it would be trivial to make it a stroker crank and to raise the compression ratio to 8 or 10 instead of the stock 4. Then while smoothing and opening up the valve ports, going to bigger valves for better breathing isn't out of the way. Offenhouser made his reputation for racing engines making replacement heads for model A Ford blocks that were both high compression and overhead valve.

The UM engine, last used, was a 318 cubic engine. So the maximum it could inhale per revolution was 159 cubic inches of air or .092 cubic feet. 110 cfm at 1200 rpm. Probably used a carburetor rated at 75 or 80 cfm. That would like about 360 cfm rating at 5440 rpm. Just a little bigger than the carburetor on a D21 gas. But google found a reference book that says the bigger engine from an E would bolt in. More displacement, different gears, more engine speed, too many variables to more than speculate on how it was done.

I expect AC spent a lot more on the tractor than what they paid Barney Oldfield.

Gerald J.

Notice in the picture above that there are no gears at the ends of the axle. Its a straight axle while the U had final drives out there. That alone could be worth a 3 or 4:1 speed increase.

Gerald J.

The U had ring and pinion from a UC with the differencial flipped.

Norm Swinford mentions those high speed 'U's in his book and he states they were equipped with a special 4th gear to get those speeds.

   Hello Guys    Has anyone heard anything about the 8N Ford tractor trying to take the tractor land speed record away from the U Allis.
   

Ab Jenkins from Utah raced him In those races. Ab later ran a U on the great salt lake Salt Flats at 69 miles per hour.