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  #11  
Old March 27th, 2021, 06:11 AM
biscaynebirdie biscaynebirdie is offline
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Default Re: Overcharging alternator and buzzing voltage regulator

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Originally Posted by Quigley View Post
I had the same problem with my 66 and put on two Delco voltage regulators and both made a buzzing sound and did not work. Bought a cheap electronic regulator from Car Quest problem solved and has worked perfectly ever since.
I’m almost wondering if they have the wiring mixed up in those reproduction regulators... It’s the generator field contact point that is buzzing, but this contact shouldn’t buzz at all. It should simply open when the engine is off, and close when the engine is started. I would have tried experimenting with mixing the wires around, but didn’t want to deem it non-returnable if something burned up.
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  #12  
Old March 27th, 2021, 05:17 PM
biscaynebirdie biscaynebirdie is offline
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Default Re: Overcharging alternator and buzzing voltage regulator

So... I checked the voltage from the positive battery post to the alternator output stud:0.2 volts. No volts read on the negative end.

However, I’m currently letting the truck run at idle at operating temp with headlights, high beams, and heater blower running. The voltage is currently at 12.3 and falling slowly... So turns out I don’t have something adjusted right in the regulator.

What’s odd is that when I checked the voltage right after starting the engine, it was at 13.5 volts (12.7 volts before starting the engine). My dad is telling me that temperature is the cause of this, but it’s only 50 degrees outside. Shouldn’t the alternator be sending out at least 13.5 volts regardless of accessories and temperature?

I’m seriously considering converting to a 10-SI and calling it quits on this wild goose chase.
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  #13  
Old March 27th, 2021, 05:28 PM
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Funky61 Funky61 is offline
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Default Re: Overcharging alternator and buzzing voltage regulator

I used this link from the Jolly Page to update to an alternator. The Mad Electrical has lots of information for the update and remote sensing.

http://6066gmcguy.com/charging.html

http://www.madelectrical.com/electri...hreewire.shtml
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  #14  
Old March 27th, 2021, 07:30 PM
James James is offline
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Default Re: Overcharging alternator and buzzing voltage regulator

Quote:
Originally Posted by biscaynebirdie View Post
So... I checked the voltage from the positive battery post to the alternator output stud:0.2 volts. No volts read on the negative end.

However, I’m currently letting the truck run at idle at operating temp with headlights, high beams, and heater blower running. The voltage is currently at 12.3 and falling slowly... So turns out I don’t have something adjusted right in the regulator.
Voltage drop is great.

With the engine idling and the headlights on high and blower running, your voltage is doing what it is suppose to do. If you was to raise your rpm the voltage will come back up. Just remember you are normally driving so the engine rpm is higher all the time and the voltage will be where it needs to be. If you have ever seen a amps curve for an alternator you will notice the higher the rpm the more amps output you will have. Proper voltage setting is with everything turn off with a fast idle (approx. 1000 rpm).

Installing a 10SI alternator will provide more amps at idle. Which is something I am planning on doing when I repair the under the dash air conditioner.
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  #15  
Old March 28th, 2021, 04:09 AM
biscaynebirdie biscaynebirdie is offline
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Default Re: Overcharging alternator and buzzing voltage regulator

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Originally Posted by James View Post
Voltage drop is great.

With the engine idling and the headlights on high and blower running, your voltage is doing what it is suppose to do. If you was to raise your rpm the voltage will come back up. Just remember you are normally driving so the engine rpm is higher all the time and the voltage will be where it needs to be. If you have ever seen a amps curve for an alternator you will notice the higher the rpm the more amps output you will have. Proper voltage setting is with everything turn off with a fast idle (approx. 1000 rpm).
I wasn’t aware of this. If the truck just stayed at idle all of the time, I suppose it wouldn’t really be a truck!

I checked the voltages at various RPMs today once I got home from work. This was done with no accessories running. Ambient temperature under the hood was 80F.

Idle: 12.9 volts
1500 RPM: 13.7-13.8 volts
2500 RPM: 14.7-14.8 volts

According to the 1963 Chevrolet Truck Shop Manual, this is right within specification.
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