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Alternator Pulley

Posted: Mon Jun 30, 2014 4:50 pm
by witty73
Hi All,

Did little post searching, but didnt find what I needed. Im in the process of converting to an alternator on my 53 new major, as many have done before. I understand that I have the 1 inch wide belt, and some later models had a narrower belt. The problem I am having is finding a pulley to fit the almost 1 inch wide belt. I have ordered off amazon, only to return because it was made for a 3/4 inch wide belt, not 1 inch. Any ideas or advice on where to find a wider pulley to fit the GM style 10 si Alternator? Any advice is greatly appreciated.

Thanks,
Witty

Re: Alternator Pulley

Posted: Wed Jul 02, 2014 12:59 pm
by BearCreek Majors
I believe most people just run the thinner belt.

Pat

Re: Alternator Pulley

Posted: Wed Jul 02, 2014 4:30 pm
by witty73
Unfortunately, the other pulleys are 1 inch wide as well. Im going to try a way over priced ebay special that claims to fit a 3/4" belt. if the current belt wont fit down in deep enough, I will try going to a 3/4" belt and see how low it rides in the other pulleys.

Re: Alternator Pulley

Posted: Thu Jul 03, 2014 12:15 am
by oehrick
Watch out witty73, vee belts drive on the sides and an alternator will put more drag on than a dynamo, if the narrow belt rides at the bottom of the drive and w/pump pulleys it'll wear quickly and slip or break - do you know a local HSM or someone good with a lathe who could turn you up a wider pulley for the alternator ??

Re: Alternator Pulley

Posted: Thu Jul 03, 2014 4:12 pm
by Pavel
What was your Amazon 3/4 inch pulley made of -- caste iron or pressed steel?
If the latter you could increase the gap between the flanges by pressing, or hammering, a steel rod between the flanges to widen the inner width -- not necessarily to the full 25.4 mm. If attempting this be aware that the flanges could break apart unless clamped together at their joint.
Bosch market a belt width of 22.8 mm [type 20A] which, I believe, sits fairly comfortably in the 1inch [25.4mm] crankshaft and w/pump pulleys. As a further check, the 20A belts have a depth of 13mm.

Pavel

Re: Alternator Pulley

Posted: Thu Jul 03, 2014 5:49 pm
by super6954
Hi Witty
Just a thought here as the purists would say your" Buggering up a classic" Putting an alternator on :cry: , But it don't really bother me as for a working tractor it's better and your still saving a classic :D . Have you looked into changing the other pulleys to run narrow belt with used ones from a wreckers. I think all pulleys fit the crank but the front seal inside Diameter might of changed ( needs confirming one way or the other) and you would have to re mark the timing notch on the pulley outer edge, but that shouldn't be to hard :idea: .
Just kinda thinking that may be the quickest easiest way to go, instead of a nearly half right fix.
Most places stock the narrow belts so replacement might be quicker than gettin funny looks at the auto store, trying to get a wide one the right size at 4 on Sat afternoon when you need the tractor :eyes: . Then waiting for someone to get it in stock as they don't carry them :cry: .

Regards Robert