Rickman48

I also have done it, and seen it done, with no damage to anything!

stellar

I have seen it done with no damage and I have seen it done with masive damage. Removing the battery from the charging circuit will cause an overcharge condition, if the alt is working. If you choose to try it yourself, put a voltmeter on the alt post and take a reading. Do not do it for more than a short amount of time. The v-reg has a set point for volts and if system volts surpass this point it can not control it. The reg controls the volts by limiting the voltage as it rises. It can not bring volts down, but only stop it from going up. Disconnecting the battery was an accepted practice in the old days by backyard mechanics, but it revealed very little anyway. All it does it tell you if the alt or genny is putting out power or if it is totally void of output. It can not tell you if the system is charging correctly like volt range or if the diodes or stator is defective. With the event of electronic parts like ign systems this practice has been discouraged for good reason. On modern cars it can cause multiple failures in the electronics. If you don't mind paying for computers, ignition system components or stereo components feel free to try it on the newer cars. In your home, nicrowaves phones and tv's dont react well to power surges.
same goes for auto electronics. The battery acts as a large resistor. Without it you will get high volts and a power surge when disconnected while running.

Scotty B

Stellar, thanks for the advice. The smoke was curling up from 2 spots on the back of the VR, and wasn't much. About like an incense stick or dying candle. I am just nervous about fire hazards. Anything else I can fix...blown motor, tranny, etc, but fire damage is hard to fix. Plus its in the garage and I dont want to burn the house down.
I'm not going to disconnect the battery because the Alt is brand new, and I have new elec igntion that I want to protect.

Anybody else seen a little smoke with a new external VR???

MDchanic

That sounds normal to me.

If you look at the back of the regulator, you can see two wire-wound resistors, wrapped around an asbestos-like material. These are designed to get pretty hot.
Any oils from the manufacturing process will naturally burn off of them

Run your car with a voltmeter across the battery terminals and see what it reads.

- Eric

Scotty B

Yep, saw the two wire-wound resistors. OK, I will crank her up again and monitor closely.

Scotty B

Update time; I now have an internal regulator alternator on the 72 442. My buddy (resto man) had an electrician bypass the external VR and fix all the other wiring and switch problems. So far, so good, but the horn still does not work. I can hear the relay clicking, but both horns will nopt beep. Hmmmm. Maybe still have a bad ground somewhere?

BILL DEMMER

check for battery voltage at the green horn wires, while somebody holds the horn button down. connect a vom or 12v test light, one side to the green wire at the horns and the other side to a good ground. if you get battery voltage, the feed side is good, then check for bad grounding of the horns, or bad horns.


bill


bill