Can you ID this alternator?
Please read this.
Identifying Chrysler Alternators (1960-1976)
The numbers in post 1 are most likely the casting numbers.
The battery was fully charged ( via battery charger ) and the voltage readings were taken with the engine running.
It’s a 1967 barracuda with a 1970 318 installed. The wiring in the car is original. I think I found my problem. When the car is running, I took readings at my old style voltage regulator. I have ~11v at the IGN terminal and only ~2v at the FLD terminal. Safe to say the VR is faulty?
Not sure what is going on but it might simply need adjustment. At voltage lower than setpoint it should switch rapidly between full field (no resistor) and feeding through one resistor. If its really below setpoint, then yes it should full field (no resistance) and votlage on both sides should be the same. I'd call 11 volts really low.
The car is simply running off the battery at this point.
The way to verify that is to look at the ammeter.
If the ammeter is pointing toward discharge while the engine is running. Then yes.
Verify by comparing voltage while current is flowing.
a. Observe the ammeter for how much current is flowing out of the battery. The meter reads 40 amps discharge to 40 amps charge, zero in center. Estimate from that.
b. Measure the voltage at the battery and the voltage at the alternator output terminal. They should be the same if current demands are low (under 5 amps) and may show some slight difference if demands are high.
c. Then compare with voltage in the ignition run circuit at a couple locations. Backprobe at the ballast resistor as well as at the regulator as you did. Voltage at both locations should be the same, and be very close to the same as measured at alternator stud.
Quick test of the regulator vs. alternator.
Jumper the regulator allowing the alternator's rotor to draw as much current as it wants.
Output voltage should immediately increase. Slightly increasing the rpm should increase the output voltage. Do not rev the engine as the voltage will follow. This will result in everything from the battery to the ignition will draw more current with increasing voltage and can be quickly damaged.
Also be careful with the jumper and do not let it contact ground. This will result a short and wirs will get damaged.
