Internal-Regulator ServiceRichard Ramsey, Princeton, MN: My son and I have a '69 Camaro we are restoring. We want to eliminate the old voltage regulator and go with the internal regulator type. I'm not sure what to do as far as rerouting the wires to get rid of the regulator. It has four wires-one large, red, fusible link, one brown, one white, and one blue. Also, directly below the regulator is some type of relay. There are six wires to this box, one of which goes to the horn. I know there is a way to bypass the old regulator but would rather delete it altogether if possible. Sure hope you can help, thanks.
Jeff Smith: You're going to like the answer to this question, Richard. The swap is incredibly easy. M&H Electric Fabricators makes a slick conversion kit that adapts an SI- or CS-style alternator to early Camaros, Chevelles, and all other early external-regulator GM cars and trucks to an internal regulator alternator. On the alternator side, there is an adapter that adapts between the original harness connector and the new alternator with no cutting required. Then, you merely unplug the four-wire harness that connects to the external voltage regulator located next to the radiator and connect the M&H plug. This allows you to eliminate the regulator altogether. Internally, this plug connects the blue field wire to the brown wire in the harness that is used as the energizer wire when the key is turned to "on."
There are actually three different GM alternators you can use to do this conversion. We're assuming you're using the most common, '69-'84 SI internally regulated alternator that is identifiable by the multiple ribs on the rear half of the alternator case. The second type is the GM CS alternator with the smaller, more compact design that was used in GM cars and trucks from '84 to '99. M&H offers bolt-in kits to convert each of these two alternators for your '69 Camaro. The SI alternator kit is PN 27555, and the CS alternator kit is PN 37787, and both are priced at an affordable $19.
If you have not chosen an alternator yet, the later-model CS alternators offer more output at lower engine speeds, which may be an advantage if your Camaro is equipped with any combination of electric cooling fans, electric fuel pump, or a high-output stereo that pulls lots of amps. The total output may be similar to the older alternators, but the newer models produce a greater percentage of their output at idle speeds, where you need them the most.
Here's another tip. Once the alternator is connected and working, use a voltmeter to check voltage output at the back of the alternator at idle. Let's say it reads 14.5 volts. Now check the voltage at the battery. If the reading is 13.9 volts or fewer, there is a significant voltage drop in the output circuit somewhere between the alternator and the battery. Start with the small wire that runs from the positive terminal on the battery to the junction block on the radiator-core support. This is usually the culprit. The spec of 0.5-volt drop is acceptable for this circuit.