Alternator V-belt pulley slipping when swapping to 3G alt

franklin2

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Addressing the title of this thread, a single v-belt will not support the power required by a 130amp 3G alternator at full output. You can expect a belt squeal at at start-up using a single v-belt. Hopefully you can get a dual v-belt setup going.
 

frankenwrench

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Addressing the title of this thread, a single v-belt will not support the power required by a 130amp 3G alternator at full output. You can expect a belt squeal at at start-up using a single v-belt. Hopefully you can get a dual v-belt setup going.
Mine has never squealed at any point even with all lights and heater on high. I am still using v belts as well. No shim, no grinding. Just bolted on and modified the wiring. I have 3 trucks with this mod. 88, 89, and a 91.
 

BlindAmbition

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Figured out why it was rubbing - I probably lost a washer when painting it.
New Old
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BlindAmbition

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How would one go about running a second belt? I see reference to it on just about every v-belt 3g alternator thread but haven't seen anyone actually do it. Searched to no avail through quite a few threads so far this morning with no results.
 

RetiringColt

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Here's a pic from the internet because I'm away from my truck, but you can see the two belts. Inside belt is for driving the alternator from the crankshaft and the outside belt is driving the vacuum pump from the alternator. Really only the inside belt drives the alternator. The outer belt is a parasitic draw from the alternator to turn the vacuum pump.
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The_Josh_Bear

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Mine has never squealed at any point even with all lights and heater on high. I am still using v belts as well. No shim, no grinding. Just bolted on and modified the wiring. I have 3 trucks with this mod. 88, 89, and a 91.
I have had the same experience with my 89. Only belt squeal has been from mashing through a large puddle.
 

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