Generator to Alternator conversion, A - Z

Just got done, took pics, now, whilst fresh in my (what passes for a) mind, I gonna tell you about it.

First step: have a generator failure on your daily.

You will need a mid - 70's GM alternator (internally regulated, large case), amperage to suit your application, though any will have more amps than your generator; and a plug repair kit. Also some metal strap, welding, and a bit of soldering.

I've not the knowledge to post pics with text to accompany, so I will write, then post pics. Should be fair obvious.

Obvious bit number 1: remove generator and brackets. In this case (1961 Falcon 170 - 6), the bracket needed to be moved and modified.

I set the alt and gen up on the pulleys, and measured the mount difference. Then I marked and re-drilled the holes. Checked the alt position, and it was good.

The alt would not pivot close enough to the engine, so I moved the mount hole up (with a bit of the strap) to give clearance. Then I made up (strap again) a rear mount, to stabilize the whole. Re-checked and position and movement was good.

Next up was the adjusting bracket. To clear the alt fan, it needed to be higher, so, again with strap, I welded a bit on at an angle to achieve the required position.

At this point, notice in the pics that the OEM generator was bodged in it's mounting by a DPO. I've no idea why he felt the need to modify what was stock Ford. Your car will probably be boogered, too. I also skipped mention of the painting: I always paint pieces while hot, seems to make the paint stick better and dry faster.

At this point, your alternator is mounted (mine was). Now to wire. I will detail an early 60's Ford, with, I hope, enough to do almost any conversion, easily.

First, you will find this easier with a wiring diagram. Not 100% necessary, but easier. On a Ford, down by the alt, the Yellow/Black 10 ga wire goes to the Alt screw post, along with the Red 10 ga wire from the plug. The Black/White 18 ga wire goes to the White 18 ga from the plug. The Black/Red wire gets taped to the harness (its the gen ground).

Over to the regulator: Remove all wires. From the ARM term: the Yellow/Black 18 ga wire gets clipped from the 10 ga Y/B and reconnected to the Black/White 18 ga wire from the FIELD term (do not connect to the reg). The Y/B 10 ga wire gets connected to the Black 10 ga/18 ga (2 wires). I did this by simply screwing both to the BAT term of the regulator. With nothing else attached to the reg, there will be no issues by doing this, and it keeps the wires neat. You may want to eliminate the reg, or isolate its terminals, either can be done but outside this article.

On any other car, you will need to find out which wires do the following:
Actuate the GEN light. This wire goes to the WHITE 18 ga at the alt plug as outlined below.
If your car has a ammeter, you will need to run a wire that is ON only with ignition ON, and run this wire to a resistor (250 ohm) then to the WHITE 18 ga wire at the alt plug. In the case of a GEN light, it provides the resistance.
The RED 10 ga from the plug still goes to the alt post.

You may want to bypass the regulator as I did, to make the job a lot easier/quicker. To do this, trace your wiring diagram to find which wire comes from the GEN light. This wire then gets connected to the FIELD exciter wire, which (on the other end, by the gen.) then gets attached to the WHITE 18 ga wire at the alt plug, separate from all else. Next, find which wire comes from the gen armature (output to regulator), and which goes to the battery and connect the wires. Be aware that, frequently, accessory power wires are connected at the regulator, and these wires need to stay connected. Wired this way, your ammeter (if so equipped) should function as stock.

That's it. Should take 3-4 hours, less if your bracketry more closely matches the alternator (I've had it happen). As you can see, the wiring is the easy bit.

Cosmo