Overcharging

[peterc]

After my beloved '72 finally succumbed to the heartless rust gods (my fault for living in Ottawa, Canada) I went looking for a replacement. Eventually I was able to get my hands on a '77 from So/Cal with a solid body, but not running (warped head/blown head gasket).

After doing the rebuild and putting everything back together I'm experiencing a problem with the charging system. There is a little red light in the voltmeter which remains 'on' whether the car is running or not (it even stays on when the key is removed from the ignition). I'm assuming that this is not normal?! When the car is running the voltmeter continually overcharges, in proportion to the engine speed.

Sounds like the voltage regulator, but I can't determine from my Haynes manual whether the '77s had an internal (in the alternator) or external regulator.

If it is an internal regulator thats gone, can it be replaced without replacing the whole alternator?

[AxtellZ]

A while back, i was tempted to swap the fuel/volt guage from a 280 into my 260.. Pete Paraska offered the following:

"Yes, the volt gage. You can just hook the plus side of the volt gage to a key-on circuit and the other wire of the gage to ground to have that working. If you want the idiot light to work, you'd have to run two wires back to the dash to work it. Basically, you want to wire the idiot light in series with the field connection on

the alternator."

Don't know that this info helps at all, but its all i could come up with at the moment! I'm not sure if the idiot light would indicate over or under-charging, or what. What does the gauge read?

HTH, Jeremiah

[peterc]

Thanks for the info axrph. I'll check and make sure that I wired the voltmeter up properly (wouldn't be the first time I installed something incorrectly. After the rebuild I actually installed the Airbox backwards. And surprisingly, the car started!! It would idle o.k but stall when I tried to give it any gas. Took about an hour before I realized what I had done

According to the voltmeter I'm definitely overcharging, with readings from 12-18+ volts, depends on how high the engine is revving.

Another question. When the key is NOT in the ignition, what should the vo;tmeter read? On all other cars I've owned the voltmeter goes to 0, but the 280's still reads 12 volts. So I'm assuming the circuit is still live.

[zorro]

Hi there,

My 260 just had this very problem last week. Was charging at around 16.5V and frying the battery, red light staying on. I thought it was the Voltage REgulator as well but it turned out to be what they call the Rectifier. It is a small metal component inside of the Alternator. Replaced this part for $30 Australian and problem solved. Hope this helps See ya Go ZED..