Fan belt

[Leewebb7]

I adjusted my fan belt a little more and have ran into an issue...before I adjusted it, I could spin the fan and the crank would turn over.....now when I spin the fan the pulley just spins inside the belt....the belt doesn't move...I think it would spin if I cranked the motor...but I'm not there in my project yet...could I have it too tight???there is some play in it..

[Glen]

Hi,
You didn't say if you tightened or loosened the belt.
Below is a page from the 1950 Cub owner's manual showing the belt tension to use.
https://farmallcub.com/rudi_cub/www.cle ... e%2027.jpg

[Leewebb7]

Sorry....I thought I tightened it... I pulled up on the fan pulley assembly as hard as I could as I tightend the nut.... so now I don't know if it was maybe a little tighter before I messed with it...but I dont see how because its as high as it will with the belt on.... I wished I would have left it alone lol..I'm pretty sure it will turn the fan once the crank turns..It's just odd that I could turn the engine over before now I cant

[Leewebb7]

Should I be able to turn the engine over by turning the fan by hand??

[tst]

if the belt is worn or glazed over , to loose it will slip

[Glen]

I pulled up on the fan pulley assembly as hard as I could as I tightend the nut....

Don't try to turn the nut at the rear of the fan shaft, you can break the casting with the slot for the fan shaft. Read the instructions on the page I posted above. You're supposed to turn the fan shaft, there is a 6 sided place made on the shaft, just to the rear of the generator pulley on the fan hub.
You probably need a thin open end wrench to fit it.
The nut is supposed to be held by the slot. Hold the nut stationary with a wrench so it doesn't turn, if the shaft is hard to turn, so it doesn't break the slot.

The fan belt on a Cub should be the right length, so the alignment of the generator belt works right.
The new fan belts I buy at Case IH make the fan shaft a little less than half way up the slot that holds the fan hub.
They don't use the bottom part of the slot except to slide the fan hub down, to loosen or remove the belt.
Don't put on too short a fan belt, I have seen on here that it creates alignment problems with the gen belt, when the fan is too low.

[Crimson Tim]

I’ve often read on here people talking about being able to turn the engine over with the fan. I was never able to do that with my Cub even though I had serviced the fan and had the alternator off once or twice, so had messed with the belt a couple of times. As other Tim says, once an old belt glazes over, you won’t be able to.

When the belt finally started to blow chunks at me and I replaced it, then yes, I could turn the engine with the fan on the new belt, no problem. Same or less tension.

Either way, it seemed to function just fine, though as the belt stretched and ultimately died, I had to adjust again to keep the alternator load from causing belt slippage a couple times.

I wouldn’t worry too much about being able to turn the engine that way (though it is handy). If you really reef on it to over-tighten a glazed belt trying to achieve that goal, you’re putting more load on the cantilevered fan shaft and the fan bearings than they were designed for. Just tension it per the specs.

My guess is yes, you probably loosened it. It can be tricky to maintain the shaft level so it slides freely in the fork, while simultaneously apply upward pressure to tension the belt. It wants to tilt while you’re lifting and jamb up on the fork. Now you’re lifting on the fork, not the belt. It’s one of those things that is easier with three or four hands.

[Leewebb7]

I made sure I only turned the shaft on the front side of the slot. But I tightened the shaft to the slot as tight as I could. I'll look at it again..thanks for the input everyone.

[Leewebb7]

Also...my belt is v notched....I don't know if that would make a difference or not as far as slippage goes