Twisted math and gear ratios for "Frankenthrower"

[shameless 3]

Hi Guys

I am modding an old MTD single stage snowthrower using the front Atachamatic mount on my 1988 312-8.

So far so good and am I ever glad your guys post pictures.

It has made this a much easier task.

The unit is mounted and the lift lever in place and its as smooth as butter!

I will post some pics of my progress and steps.

Tommorow I start adding pulleys, idler wheels and tensioners to make it all work.

There are no pulleys on the snowthrower at present, the gear box is in tact with chains and gear moving smoothly.

There is a shaft that exits the gear box, which is where I will start.

Pulley #1 will connect to the shaft that exits the auger gear box.

Pulley #2 with a tensioner would be above Pulley #1 to bring me high enough to clear all structures.

Pulley #2 will be connected to a keyway shaft running through a pillow block bearing.

Pulley #3 will be on the other side of the pillow block bearing from pulley #2 to allow me to line up with the pto pulley on the tractor.

An idler pivot wheel and pulley set up will keep the belt tension tight between the pto output and pulley #3

The pto pulley is 3-1/4" diameter in the belt raceway.

I think it would make sense to match pulley size in each step to maintain a 1-1 ratio.

THE QUESTION???????????

What size pulley should I be using for pulley #3 to attain optimum auger speed for throwing snow???

[shameless 3]

hello all!

I ran into a snag before any of you could reply.

The motor and the snowthrower turn in opposite directions!!!!

[Kelly 1,033]

Post a pic that way we have a better idea of what your dealing with.

[shameless 3]

I will send some pics today.

I am almost done with the drive and tensioner, just need to know pulley size for blower.

"Thanks TT" , I used your pic from a year ago to design a gear set to change the motor versus blower rotation.

building that today......

Should be able to test fire tonight!

[shameless 3]

Update and question:

Here is the drive setup.

These images are in my post "The journey to get to the result", but since my question was originally asked in this post I thought I would ask again and show the ALMOST final prroduct.

Belt at the PTO is on the outside groove (3.5" diameter).

Large pulley on blower jack shaft is 7"

This is the pulley that can be changed to adjust final drive ratio.

The large pulley connects the jack shaft to the gear drive.

The gear drive is there to change the direction of the blower.

The gears are all 2"

The Question......

What rpm is the blower supposed to spin at?

What size pulley should I have on the blower jack shaft?