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Old 05-11-2016, 10:25 PM   #1
hevymetl
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High voltage from alternator

Finally got my '66 registered and on the road. It seems that it has the internally regulated alternator swap done already since there are no wires going to the old voltage regulator. I installed a new battery a couple of weeks ago since I didnt know how old the current one was. I tested the voltage at the battery and at the back of the generator. At idle I got over 15volts, and at high idle I get high 16s. At idle with lights on I get mid 13s. Im thinking this is pretty high no? What say the experts? Thanks in advance for the help.

John
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Old 05-11-2016, 10:41 PM   #2
Wrenchbender Ret
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Re: High voltage from alternator

Way too high. You probably have a bad regulator in the alt. if it is an internal reg. If it is still the original type alt. someone may have bypassed the regulator.
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Old 05-11-2016, 10:57 PM   #3
hevymetl
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Re: High voltage from alternator

10-4. I will have to look into wether its still the old alt or not. Thank you for the reply.
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Old 05-11-2016, 11:31 PM   #4
Tazimafied
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Re: High voltage from alternator

Most internally regulated alternators for GM have a flat back.


The externally regulated alternator will have a "step" in the back.


There are a few different way you can go with this depending on which one you have.
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Old 05-12-2016, 12:10 AM   #5
hevymetl
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Re: High voltage from alternator

I'll investigate and report back.
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Old 05-13-2016, 03:16 PM   #6
hevymetl
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Re: High voltage from alternator

Just pulled the alt. Appears to be the external type. Guess I'll pick up a internal type since it seems to have had the external regulator bypassed already.
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Old 05-13-2016, 11:24 PM   #7
Tazimafied
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Re: High voltage from alternator

If it doesn't have the bypass there are cheap kits out there to get the job done.
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Old 05-14-2016, 09:05 AM   #8
Palf70Step
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Re: High voltage from alternator

You can check out my thread for the conversion (starting with #128). It also has links to others. The only thing you'll need beside the alternator is the plug for the alternator. You can undo the current wires, ditch the regulator and extra wires and have a clean setup that works great.

http://67-72chevytrucks.com/vboard/s...=627495&page=6
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Old 05-14-2016, 09:31 AM   #9
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Re: High voltage from alternator

The old #12 output wire if still OK I hook to terminal 2. Because of the larger capacity of the replacement I run a new #8 for the output. Brown wire for the light goes to terminal 1.
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Old 05-14-2016, 02:49 PM   #10
hevymetl
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Re: High voltage from alternator

Thanks for the help guys. I followed one of the threads in the FAQ thread. I basically cut the regulator plug off, connected the blue and the brown together, ditched the white, then at alt I connected the blue to no.1, connected the batt wire to batt terminal along with jumper from batt terminal to no.2.
Seemed to work fine. Normal voltage (14.6ish) at all rpm ranges.
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