Hi all. Got my 57 Meteor out of storage a few weeks ago. Original generator and regulator configuration.  Fired right up but the voltage gauge has been erratic. It shows 12 volts when key is turned on. Once car is running it will bounce around from anywhere between 12 and 14 volts. On the highway it will gradually climb up towards 14 volts but then starts to flutter again. I'm thinking regulator malfunction. Any suggestions appreciated. Thanks

Hi all. here's an update. Turns out it was a defective regulator on it's way out. Replaced it with a new one however the new reg was a 35 amp 12v compared to the original 30 amp 12v. Upon firing up the car the voltmeter on the dash as well as my multimeter indicated 16.3 volts. Too high. I was able to return to supplier. Through my local Ford dealer I was able to locate a correct 30 amp manufactured by Standard Products made in the USA. That was stamped on the back of the reg. The other reg was made in China. Got it installed and got 14.2 volt right away. Great. Now another question. I have the vintage 57 Ford manual for this car and it indicated that the voltage rgulator is temperature sensitive. News to me. I took the car out for a ride and the ambient temp that day was 94 degrees F. The longer I drove in stop and go traffic the voltage started to drop from 14.2. On highway driving I maintain 14 plus volts. The only thing I can think of is more air coming through front end the cooler the regulator. Can anyone explain how or why temperature impacts on generator or regulator output. Thanks in advance

Wire wound resistors are used to sample and regulate.  As temp goes up so does the resistance.  Not much, but it does increase.  That changes the voltage sampling values, (they use voltage differences to determine charge) thereby the output will vary.  Again, very small changes but changes that impact the output.  You'll find in cold weather the regulator stays spot on.  The resistors are able to dissipate the heat and remain constant value.

Thank you. So it's the 2 resistors under the regulator that are affected by temp change. In the position they are in on the rad cradle the air flow is restricted. Does it make any sense to supply more air flow under the regulator to maintain consistent temperature or relocate to a more favorable location

Personally I would not mess with it.  The 14V + or - a couple of tenths will not impact charging.  If it were to fall to 12V then it's time to move/modify mounting.