Conversion shaft for cub PTO

[kluf357]

Does anyone know if there is a conversion shaft for the Farmall Cub 480 PTO to a 560 or 1000 RPM PTO. I'm doing a research project for one of my classes and want to be able to hook up my 1964 Cub to a dynamometer so I can compare the horse power loss to the International posted values and the Nebraska Tractor Test Lab.

Any ideas would be helpful or if anyone knows where to get a conversion shaft that would work to.

[Puffie40]

The cub PTO has no reduction - it runs at engine RPM. I don't think there were any reduction gearboxes available either due to the cubs low horsepower.

The PTO did have a flat-belt attachment available, so horsepower could be calculated using a prony brake. The other option is to build a jackshaft connection using a pully on the pto - there are pulley bushings available that fit on the cub splines

[Matt Kirsch]

There is an adapter sleeve that converts the Cub PTO to standard 6-spline, but it is still running backwards at engine speed. Unless the dynamometer can handle that, you are out of luck.

There are also reversing gearboxes that convert the Cub PTO output to standard 540RPM, but they are rare and expensive. Probably not something you can swing on a student's budget. They will also severely skew your results. Losses through the gearbox, and all.

Nebraska tests 386 and 575 only shows belt and drawbar, no PTO. So, you have no PTO information to compare to anyway.

[Eugene]

PA-13 is the part number of the adapter sleeve converting the Cub's pto shaft to standard size. Not sure if the number is still good or that was the local IH dealer's part number.

I purchased the sleeve adapter perhaps 15 years ago. It's still sitting on my desk, just to the left of the computer screen. I haven't found a use for it - YET.

Next problem. The Nebraska tests were conducted with factory fresh tractors and finely tuned, standard engines. Any thing less than a factory fresh engine, results of the dynamometer test will be skewed downward.

[kluf357]

"Next problem. The Nebraska tests were conducted with factory fresh tractors and finely tuned, standard engines. Any thing less than a factory fresh engine, results of the dynamometer test will be skewed downward."

I expect there to be i'm an Agricultural Engineering student and am running this experiment to show the efficiency loss over time. I'm planning on following there test standards as closely as possible to try to get the most accurate results. The only reason I want to use my cub is because my other tractors are currently not in running order. I was thinking about just rigging up a chain drive to a 540 spline and connecting it that way. If my predictions hold true there should be around a 1.5-2 hp drop. Currently my other option is to use a farm operations D17 Allis, but hooking up an inline fuel flow meter for a diesel will be sort of tricky.

[Matt Kirsch]

On a Cub, 1.5-2HP is 15-20%. That's a huge skew.

Too bad you can't find a belt dyno.