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Hey guys, I got a new set of pullys (crank and water) and the crank pully is like 3/4 of an inch smaller. So now my belt is too big. I realize I can just get a smaller belt and it will work. But, my dad was saying that it could possibly mess up my alternater(a smaller belt that is). Is this possible? I just wanna be extra careful I dont want to blow anything or burn anything up.
 

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A larger crank pulley will spin the altenator a little faster which is good for low RPM operation. Most altenators are good for 18000 RPM and can surge higher. As long as you are not cruising at 5000 or 6000 RPM all day long you should be fine.
 

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A larger crank pulley will spin the altenator a little faster which is good for low RPM operation. Most altenators are good for 18000 RPM and can surge higher. As long as you are not cruising at 5000 or 6000 RPM all day long you should be fine.
wouldnt a larger crank pulley spin the alt slower
 

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He said the crank pulley was 3/4 inch smaller. This is an under-drive setup. The alternator and water pump will both turn slower which saves power but may also cause overheating and battery charging problems (especially with a one wire alternator) if your engine is at idle a lot. If so, you'll need a shorter belt or get the standard size crank pulley. Were these March pulleys? The make a standard drive set. Can you return exchange them?
 

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He said the crank pulley was 3/4 inch smaller. This is an under-drive setup.
Thanks Paul, I miss read the post

I dont mean to hijack but, please explain?
It is a ratio thing. If the crank pulley circumference is 3 times the size of the alt pulley, then alternator will spin 3 times the speed of the crank. If the Crank pulley circumference is 3.25 times the alt pulley, then the alt will spin at 3.25 * engine speed.
 

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Thanks Paul, I miss read the post



It is a ratio thing. If the crank pulley circumference is 3 times the size of the alt pulley, then alternator will spin 3 times the speed of the crank. If the Crank pulley circumference is 3.25 times the alt pulley, then the alt will spin at 3.25 * engine speed.
lol yeah i got it now.....i kinda confused myself a little bit
 
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