I just upgraded my stock '74 Delco Alternator (I have the 63A one, Auto and A/C), with an 80Amp upgrade kit from Alternatorparts.com (this isn't their fault, I don't think).

Anyway, upgrade parts went in fine, all the instructions were quite clear and everything fit as it should.

However, when I put the alternator back in, I fired it up and things looked great, Ammeter read 12 at idle, which is MUCH better than the 1 or 2 I was getting with stock. This was a good thing, but good things are short-lived, it only lasted about 45 seconds or a minute, then I got electrical smoke, and something was definatley wrong. I shut it down, and things definaltey were messed up.

I disassembled the Alt again, and found that at a minimum, the diode trio is toast, maybe other parts, too, but haven't gone that far. It'll definaltey need a new kit.

Anyway, my question really is about how I have things hooked up. This setup worked just fine on the stock alternator, there are two places to hook up on the back of the alternator, one labeled "Bat", and the other unlabled, but is near the dual-spade connector. I don't recall at the moment (and can't test), but I'm not sure if they both have permanent power or if one only has power when the alt is spinning (I think the bat terminal is this way). I have some accessories hooked to the bat terminal and some to the other (Stereo Amp, Dual-SPAL fans, Radio battery power, etc.), I don't recall at the moment using any logic to where I hooked things up, just used whatever worked. Question is, is this wrong? Is there a specific purpose to each of the posts, and is it wrong to hook anything not intended up to one post over another? Is this why I fried the new parts, or did I do something else wrong? Like I said, the upgrade went smooth.

Thanks,
David

 

Hello DJ.
Well the 2 red alt wires (or 1 of red wire switches to black later in the harness) can go to the same spot (red wire junction on drivers fender skirt) while the brown wire goes to the iginition sw (through the fire wall). Those red wires connect to the battery through the starter solenoid (large term lug) through that fender junction. There is a black wire used to gnd the case (to engine block or harness or what ever).

To troubleshoot u need a good alt and need to disconnect what u can. Cooling fans can stay off until ur engine heats up - temp gauge work? But the stereo and accessories can be disconnected. Draw up ur own diagram for ur current loads and use ur amp meter to measure current on each by one at a time and record current - u need to switch the meter leads to current for this. Is ur current load(s) too hi for ur fuse? Is everything fused?
If u need to u can disconnect each wire from each device connected to alt and/or harness and measure resistance to gnd (with battery diconnected) - this will show u a short to gnd if low resistance (<5ohms).

Install a new wire harness yet? I know this would be a piece of cake for u and would eliminate old insultation porblems. Just do one side on the engine compartment at a time and take ur time. I left every thing connected on mine and removed one side of firewall plug at a time. Then just unplug 1 connector at a time and then plug in new harness connector. Tricky feed through the fender skirt for the headlight wiring but since u have replaced the radiator before should be easy for u. The starter side will be even easier just remenber the A/C harness is separate and comes through the p-side of firewall on its own. BTW NAPA sells the dialectric greese for the firewall connector.
This should make u 1 with ur wiring and will be able to chant montras as u work - ohmmmm, ohmmmm.
Sereously i think u should run the cooling fans off a relay and a dedicated fuse for them.
Hope this helps. cardo0