Hot Squealing 3G alternator conversion

scrutmonkey · Aug 13, 2007

1968 coupe, 289, running 3G 95 amp alt from RJM Injection.com....dual V belts. i have some high pitched sqealing on mid rpms and alternator is really hot to the touch after about 20 minutes with the engine at idle.

wires are hooked up correctly, 175 mamp fuse and harness connections are correct as well. Amp is charging battery with no electrical drain.

Are the V-belts not enough to stop from squealing? Do i need to run a serpentine setup then? Why is the 3G so hot?

I'm thinking about scraping this whole "upgrade" and going back to the old style alt.

Rusty67 · Aug 13, 2007

Thats the first time I've heard of this problem. Have you checked the belt tension ? Maybe you have too much tension on the belt. Also, why do you have 2 belts running the alternator ? Are the pullies the same size on both ends ? If not then that would cause a problem. Can you take a pic of it ? I have never seen 2 belts driving an alternator before.

scrutmonkey · Aug 13, 2007

well, i had one, but the squealing was unbearable. pops said back in the day, PS wasn't even used, a dual V-belt was for added safety and in my case, might help in keeping the V-belt from slipping....which it does since it only squeals a little when I rev the engine.

I ran a seperate line to the 904 wire at the old regulator circuit since running the green/red from the #35 was draining the battery.

Kinda of dark now, ill take a pic tomorrow. The closer V-belt is aligned perfectly with waterpump and bell. Bastard still squeals with only one belt.

@ belts, outermost v0belt is a little misaligned, but no squealing.

Alternator gets hot both ways, probably due to friction caused on the belt. belts are brand new as well. haven't tried any "belt dresing" as old posts have stated. The hot alternator is what is worrying me.

DK832 · Aug 13, 2007

I swapped to a 100 amp and had problems when revving really fast when drawing power (lights, fan, heater, car pc). The engine would spool up faster than the belt could make the alternator do = squealing. Really annoying! Tried more/less tension, new belt. Ended up swapping to a cog belt drive like the NASCAR guys use. Nice little whine to it as a bonus.

rbohm · Aug 13, 2007

it is possible that the pulleys are worn too smooth to allow the belt to grip properly. as for the alternator getting hot, remember that you are making alot more amperage than stock. you have an alternator that makes 3 times the amperage the stock one does.

rsev216 · Aug 13, 2007

I had a lot of squealing when I first installed the 3G. The belt slippage resulted in a very hot alternator. Switching to the Hi-Po pulley solved the problem.

Tim65GT · Aug 13, 2007

My 3G squealed when starting or reving it. Fixed it with a double v-groove setup. Is your 3G new?

The red/green wire should go to a switched ignition source and should include a 560 ohm resistor or the "alt" lamp in the circuit.

scrutmonkey · Aug 13, 2007

yes, 3G is new, running the double V groove belt as well. Are the HiPo pulleys larger in diameter so it has more surface area for the belt to grip and spins slower?

rsev216 · Aug 14, 2007

scrutmonkey said:
yes, 3G is new, running the double V groove belt as well. Are the HiPo pulleys larger in diameter so it has more surface area for the belt to grip and spins slower?

Yes, the Hi Po is larger providing more surface area for the belt to grip and it turns at a lower rpm than the standard.

Hot Squealing 3G alternator conversion

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