OEX alternator

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Offline Slugger

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  • Name: Cory
OEX alternator
« on: March 29, 2021, 02:30:17 pm »
Has anyone had any experience with these alternators?


I've got a 5.5 inch crank pulley, 2.125 inch alternator pulley and it's just not making enough power unless i rev it over 3000rpm. The only time i've seen it at 14.2v was on the test bench, where i forgot to ask what RPM he ran it to.

I've got a new AAW harness. 6 gauge cable running from alternator to battery in the trunk, 6 gauge cable running from bat neg to engine, plus a 1 gauge to the frame. 12 gauge main harness feed. Driving along, and the 25amp fan kicks in, the voltage drops down to below 12v. and that's with the fan directly off the alternator output. It's an 85 amp alternator, surely that should keep up. regardless of rpm.

during testing, headlights, A/C and thermo on, drops below 12v.

I've got a mobile auto electrician lined up in a week or so, but deciding whether or not i should just buy a 3G high output to put on. it'll probably be the same price as the sparky.

Offline Slugger

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  • Location: Tamworth
  • Name: Cory

Offline AussiePhil

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Re: OEX alternator
« Reply #2 on: March 29, 2021, 07:11:51 pm »
Hey Cory,
Firstly I'm not electrical at all!
What is the alternator on and does it have an external Voltage regulator.
Early Mustangs had an external Voltage regulator.
Later cars like the 3G are connected to the alternator.
I run a 3G and it's runs beautifully!
Cheers Phil.
If you've never buggered anything you've never done anything!
But if you've buggered a lot maybe you're not very good at it!

Offline Slugger

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  • Posts: 163
  • Location: Tamworth
  • Name: Cory
Re: OEX alternator
« Reply #3 on: March 30, 2021, 10:08:33 am »
It's on a 66 with a 302. All new wiring harness with no voltage regulator.

I bought the one in the link above, 80 amps at idle should be good. hopefully install it today or tomorrow.

Offline AussiePhil

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Re: OEX alternator
« Reply #4 on: March 30, 2021, 05:37:35 pm »
Hey Cory,
Sounds like you're on track!
Good luck with it!
Cheers Phil.
If you've never buggered anything you've never done anything!
But if you've buggered a lot maybe you're not very good at it!