The Stovebolt Site Forums The Shop Area The Electrical Bay 53generator to 77 alternator

The 77 alternator doesn't use a regulator,what do you do with all those wires that go to the regulator and what wires go to the alternator?Do you still need to do anything else to convert over to a 12 volt ignition? I think I know about the lights and gauges,etc.
Lothar

I'm not sure which alternator you are referring to, but if it is one of the GM si series, the big wire from the post goes to the battery through the ammeter and there is a "sense" wire from the regulator that goes to the battery as well. Then there is a 3rd wire that can be left alone or run through a light bulb to a key switched source, that gives you a charging indicator and makes the alternator charge immediately when you start the engine.

The other wires to the regulator are not used.

You need a ballast resistor for the coil when you change over to 12 volts.

KillerKnight,

In lieu of a ballast resistor, you could use a internally resisted coil.

Your new alternator could have its BATT output attached to the wires that went to the BATT terminal of the old regulator. This might have had two large wires the were tied together and went to the horn relay.

The DA plug adapter should have two wires. The wire from #2 could be wrapped around and attached to the large BATT terminal. This will work fine.

The wire marked #1 (smaller & sometimes white) has to be switched ON when the key is turned on. This could be a terminal on the keyswitch or even the key side of a ballast resistor if used.

This wire can backfeed voltage, so if it isn't in a circuit that is switched open by the OFF function of the key, a small diode can be put in series to stop any power from being backfed.

The remaining wires to the old regulator can be taped up separately and the regulator removed.

This information assumes your alternator is a SI unit and doesn't require a external regulator.

Many alternators look similar..some of the older versions had similar plugs etc, but still used a external regulator, but not your old generator regulator. Are you sure of the unit you have.

There are other details of the swap from 6 volt to 12 volt, but those can be addressed as they pop up.

EDIT. Does this truck have a different engine in it now. Your profile mentions a V-8 somewhere, so my post might not be pertinent!

Stuart

The alt is the internal reg type that they used in like 73-77 Chevelle.Yes I'm using a small block V8 with the HEI.

KillerKnight,

Your HEI will want full battery voltage, switched by the key of course. It might be helpful to update your profile to include your new SBC powered truck. Send some pictures when you get a chance.

Stuart