Belt / Pulley Combo

[BrianX128 107]

Anyone ever put a engine with the smaller drive pulley (4" versus 5 1/4") onto a tractor that is a hydro? I'm curious what sized belt will work best on this. The stock belt that was on the 417A I'm dealing with is way too floppy at the engine to spin the hydro. I'd just put the larger pulley on, but it seems the set screws rust welded themselves in the pulley and I've read of people leaving the slightly smaller pulley in place with no issues, but I'm curious what belt they used when doing this. The hydro belt is 81.5" from what I've read, I'm thinking an 80 would be the sweet spot but I'm not sure if that's too small or not small enough. 

[71_Bronco 1,072]

May have to just get a couple, try them, and return what doesnt fit. I think there's a way to get a rough estimate with string, but I dont know exactly how to do that.

 

The other thing to look at is your belt guard. Not sure if the slightly different route of the belt will make it rub or not.

[BrianX128 107]

I'm hoping I'm ok there since it's still a hydro like it was, I pulled the belt tight towards the front of the mower and it looked like it was going to ride the same path it had before, but I have the belt gaurd from the manual tractor as well if I need to swap it for some reason.

 

I guess if nothing else this should be slightly easier since the belt doesn't have to move with a clutch pedal like on a manual. Just have to get it tight and in the right path and I'm good to go.

[71_Bronco 1,072]

10 minutes ago, BrianX128 said:

I'm hoping I'm ok there since it's still a hydro like it was, I pulled the belt tight towards the front of the mower and it looked like it was going to ride the same path it had before, but I have the belt gaurd from the manual tractor as well if I need to swap it for some reason.

 

I guess if nothing else this should be slightly easier since the belt doesn't have to move with a clutch pedal like on a manual. Just have to get it tight and in the right path and I'm good to go.

 

Agreed, on some of the manual tractors, the guard helps keep the belt in place when the clutch is pressed in. Hydro is a little different.

[8ntruck 7,083]

Try a belt about 2" shorter.  

 

Pulley diameter difference =1.25".  Assuming 180 degrees of belt wrap and same center to center difference of the pulleys, the belt difference can be estimated with:  (1.25 x 3.14)/2 = 1.92"

[BrianX128 107]

80" works perfectly, I'm going to have to see how long the pulley goes without hurting the belt now. It has a 1/8 tall chip missing on the top of the outside edge of the pulley where the belt rides about 1/2 an inch long. Nothing sharp and the belt shows no wear from it.