IH Danco BB36 gearbox repair

[SLS327]

The gears stripped on the gearbox as seen in the background on the photo, today replaced them with a used set. Should be good to go for the weekend. Does anyone have data on what the speeds of the augers/rotors are recommended to run at, because I have a different setup using the bb36 snowthrower on a 127?
DSC04460 (400x266).jpg

[Berwil]

Here is a chart that gives the gear ratios of different gears boxes. Most throwers are 2:1, so the driveshafts to the smaller gear are spinning at 1800rpm. The bb36 is 1.5:1 so the driveshaft is spinning 2700rpm (?). Short of counting teeth, I'm not sure of the gear reduction to the auger.
http://www.onlycubcadets.net/forum/s...ead.php?t=7866

I thought the bb36 is made only for the original. I am pretty sure it has a smaller pto pulley than a 127. If your running your 127 wide open, your spinning it too fast unless you changed the gearbox input pulley diameter to compensate.

Bill

[SLS327]

Wide open throttle, generally. I'm learning what I've got from this site and what it was used for, thank you for the gearbox information! It works really well, the faster the better. I bought the setup, someone used a NF mule drive from something else and bolted it to the auger frame, similar to the way an original mount went on there.

[ol'George]

Easiest way is to do the math.
Figure what your drive pulley diameter is on the motor, vs the driven on the gear box, take that ratio to get Rpm, factor the box 1:5 to 1, take that ratio/rpm then figure the small sprocket teeth vs the large sprocket on the auger & factor in that ratio/rpm and you will have the theoretical auger RPM.
It sounds way more complicated than it is.
As ppl change driven pulley diameters, gear boxes with different ratios. and small drive sprockets your rpm's can vary, or be varied.

Say for instance, your gear box needs an orthodontist,
it is a 2:1 ratio.
you can't get what you need quick, and it is still snowing.
You have a 1:5 to 1, setting on the shelf for your tiller.
No problem, mount it and change your small sprocket a few teeth on the
drive shaft of the thrower.
ya you might have to go to tsc and get a sprocket and do some drilling.
but easier than hand shoveling. BTDT

[SLS327]

It is running the auger/rotor too fast and I will probably throttle back a bit. After looking at what the original had compared to the 127, its geared up a bunch. Interesting how it was intended for that but works really well on this....
engine pulley/grbx 1.2 increase, grbx 1.5 decrease, sprockets .4 decrease = 1152 rpm

got some chains too with the grbox thrower deal, so I will get those put on too.

[ol'George]

Ideally you want to run your engine @ full rated Hp--3600
and if you have the hp to run the thrower fast/faster(not the engine) it works better.
Granted, there are instances where slowing it down is desirable like not wanting to blast snow @ a building/vehicle.
But keep it's mouth loaded and gov full open, especially in sloppy wet snow.
An operator gets a feel for how fast/slow to go by engine sound and where you want/how far you want to throw it.
if one is modifying the ratio's, trial/error is the way to go.
When you get too much auger speed you loose Hp real quick,
too slow and if just glops out like the rear end of constipated dog.