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Old 01-11-2018, 07:22 PM   #1
snaus32
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single wire alternator

I have a new motor im instilling in my 67. Its a crate L31 vortec and has a single wire alternator on it. How do i wire it? My 327 had the two wire set up, I have the positive wire but where do i hook up the white lead for the voltage gauge? do i just put them both on the same terminal?
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Old 01-11-2018, 11:26 PM   #2
sleepertruck72
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Re: single wire alternator

https://www.summitracing.com/parts/p...ss-performance

I did not use a volt gauge, but I used this painless wiring pigtail...after I found out my alternator fried because I didn't have a charging lamp as a load in the circuit
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Old 01-12-2018, 12:52 AM   #3
VetteVet
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Re: single wire alternator

The best place to wire it is to the same place the original alternator output wire was ran. Inside the harness is a soldered junction with four red wires connected together, it is located in the main harness by the left headlight. They are all 12 gauge wires and one of them comes from the battery over the radiator, one goes from the junction to the firewall connector for cab power, one comes from the external voltage regulator, and the fourth one is the output wire for the alternator. If you don't plan to upgrade this wire to a 10 or 8 gauge, you can just splice it to the red wire from the voltage regulator since you will not use it any longer.


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Here is what the junction looks like in my 67 harness. If you have a gauge dash panel you will also have a black or black/white stripe wire also connected with the four red wires. It is for the battery gauge (ammeter), and there should be a solid black wire connected to the junction bolt on the right fender by the battery which is the other battery gauge wire. If you wire the one-wire alternator to this junction bolt like so many guys do, the alternator will charge but the battery gauge will not show any charge or discharge.

Here's a picture of the soldered junction.

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Old 01-12-2018, 12:29 PM   #4
AK49Watson
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Re: single wire alternator

I also used a new internally regulated single wire capable alternator, but wired it the original way using the same method above. Works great. I have a factory ammeter, didn't bother wiring it up though.
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Old 01-12-2018, 02:02 PM   #5
VetteVet
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Re: single wire alternator

After posting the diagram above I noticed that it was the one that shows how to convert to the internal regulator alternator by jumping the wires in the external regulator plug. All that's needed is an adapter plug for the SI alternator,which is about $5.00 at the auto parts store. No resistor is needed for this conversion and running the blue wire to the no. 2 terminal on the alternator will reduce any voltage drop on the circuit.

With a one-wire alternator, the blue and white wires would not be used and only the large red wire from the back of the alternator needs to be run to the main junction.

Here is how I convert the alternators. It is much cleaner and eliminates the external voltage regulator plug and it's wiring.

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Simply run the brown wire from the firewall connector to the no. 1 terminal on the new alternator and run the red wire from the junction to the no. 2 terminal on the alternator. Then upgrade the 12 gauge wire on the back of the alternator to 10 or 8 gauge and run it to the main junction.
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