Alternator bad? Verify my troubleshooting please.

[Juggernaut]

Originally Posted by undy

What manufacturer and model alternator are you currently running? A lot of Cobras run the GM alternators, especially the 1 wire ones. Your alternator sounds like it's definately bad. My GM 100 amp 1 wire puts out 13.8 VDC @ 65 amps, at an idle. Mine's also convertable to a 3 wire setup. Doing so will give me the full 14.5 volt alternator output. Mine's a Powermaster. I plan on doing the mod in the near future in conjunction with my new cooling fan install.

Also, make sure your charging circuit/wiring is up to the task of a 100 amp alternator. Painless wiring and others typically are not. I run a #4 copper wire from my alternator to my fuse block/starter/battery and #8 copper to my engine cooling fan.

Undy, it's a Summit alternator, SUM 810304 for a 289, their name brand. Not sure of the wire size from the alternator although 4 sounds right, I can check on that.

Also, yours runs 13.8 VDC @ 65 amps, where does the advertised 100 amps come in, see I need a little education on this electrical stuff.

Is there an advantage to running a GM 1 wire alternator over a Ford one? Where would I get the Powermaster for my 289?

Thanks,