Flat belt flying off

gustafson · Mar 21, 2019

Ideas?
42 MG owned over 20 years.

Belt that came with it finally rotted in two. Bought leather belt 'kit' a while back and made one up.

Comes off virtually every start. Or else pops off the tensioner and comes off next time

Is crimping the belt that fussy?

If I pull the belt in board on the top pulley it will stay on but that is tedious

Mark Rand · Mar 21, 2019

I'm guessing that either the new belt is slightly longer on one side than the other or the old one had been and was corrected for. Presumably you can change the alignment of one end (move the motor mounts???) to stop the belt coming off. Same as aligning a band saw blade.

rakort · Mar 21, 2019

Two things come to mind..

1) crown on the pulleys has been worn away causing belt tracking to be more sensitive...need some crown there.

2) the splice wasn't made square/parallel causing one side of the belt to be under greater tension than the other side.

I have a similar issue on my southbend, but that was more related to pulley alignment.

Thinking about my 10EE I don't believe there is too much opportunity for pulley misalignment but sure worth checking. I'm going back to the belt/splice since nothing changed on the machine between the old and new belt.

gustafson said:
Ideas?
42 MG owned over 20 years.

Belt that came with it finally rotted in two. Bought leather belt 'kit' a while back and made one up.

Comes off virtually every start. Or else pops off the tensioner and comes off next time

Is crimping the belt that fussy?

If I pull the belt in board on the top pulley it will stay on but that is tedious

wheels17 · Mar 21, 2019

Can you buy a serpentine belt of the proper length and run it inside out? It will be quite precisely made. If it stays on, it indicates a belt problem and you can run the car while you sort out the belt. If it flies off too, there is probably a problem with wear or alignment.

220swift · Mar 22, 2019

Find the correct belt.
There are better choice than leather belts.
Monarch did a lot of R & D on which belts to use.

Hal

TDegenhart · Mar 22, 2019

If the splice was with pin and clinch, turn the belt around and see if it flies off the other way.

Tom

rakort · Mar 25, 2019

were you able to resolve this? I know the problem can be frustrating.

rimcanyon · Apr 6, 2019

My 1940 10EE will throw the flat belt if I try and make too heavy a cut. I've found that I can adjust the rear idler pulley with a bit of a bias towards the tailstock and it will help.

gustafson · May 4, 2019

Looks like I got it figured out, appears more care was needed in assembling the belt.

A little more accuracy than is usually expected when something is assembled with a hammer........

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Flat belt flying off

gustafson

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Mark Rand

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rakort

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wheels17

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220swift

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TDegenhart

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rakort

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rimcanyon

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gustafson

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