Alternator belt problem

[RLG3]

Hey y’all, new around here, and I was hoping to get some advice on an issues I’m having, probably an easy fix I just don’t know about

I have an 82 K5 with a rebuilt 350, but I’ve been having an issue with the alternator accessory belt, or really the pulley on the engine…
It appears that the pulley is grabbing the belt and holding it for too long, making it shake like crazy. I’ve tightened the belt but that hasn’t fixed the problem, my alternator is keeping up good when driving, but seems to keep up less (the dial drops like a brick) whenever I stop or use any electronics (windows, AC, lights, etc.).

it’s a fairly new problem, and I want to get rid of it before something happens. My best guess is that I should replace the belt, even though (as far as I know) it should be fairly new, but in this case it seems like the main pulley on the engine is the problem.

any help I’d greatly appreciated, thanks!

 

[Wes Harden]

Odd does the pulley look damage/bent?
As the the charging, alternators work best around 2000 to 2500 rpm.
You should still have better performance than what you described.
1st check the wiring to the big stud at back of alt. Many of us replace the factory wiring with a larger gauge wire. Factory is 10 gauge, 8 would be next step up. New clean connections will make a difference as well.
Check that you have good grounds, most run at least 3, main and largest to engine block, clean and unpainted, avoid exhaust manifold, or brackets.
2nd to frame can be same size or little smaller gauge wire.
3rd to radiator core support, minimum 10 gauge wire.
Also with a volt meter compare battery voltage to the votlage at back of alt. Engine off. Ideally it would be the same, but real world it will be less more than 1 volt less indicates high resistance.

 

[RLG3]

Well, I pulled the belt off and I think I’ve found the problem, the belt looks to be very worn (it looks like it’s practically hollow ground) and the thread is splitting apart, so I’ll be replacing that ASAP and hope the problem goes away. Any recommendations on what belt to use?

 

[Wes Harden]

Not a cheapy, Gates or Dayco. they make multiple levels of quality I usually go for the $15.00 mark.

 

[RLG3]

Thanks! I picked up a dayco top cog yesterday morning (15445) and threw it on in the parking lot, cost me about 20 bucks at advance auto. The “pulley grip” problem is gone (old belt was pretty torn up and was recessed into the pulley) and the voltage output is a stable 14.2 or so volts, so that does seem to have fixed everything.