'66 Barracuda having some charging issues

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1974DartSwinger

1974DartSwinger

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Hey guys, I went on a 2 hr trip up north for a car show last weekend and had zero problems, even in the 95* heat she ran nice n' cool. Got back home fine too. About 15 min from getting home I noticed that my Amp meter was in discharge while driving. Nothing was wrong that I could tell so I pulled the headlights on to check the meter and it dipped even lower into discharge. Reving the motor didn't do anything. I'm thinking my alternator must have died. All week was busy so just this morning I ran out with the volt meter and battery is 12.4V with car off and the same with engine running. I read another post here about jumping the single green wire on the alternator to the alt stud but that didn't do anything accept spark and make the car almost cut off.

One WEIRD thing I did just remember was that when I first started her up this morning, it did show Charging on the amp meter, just like it always has. After it warmed up for a little bit it was back to discharge. My gut says its the alternator . . . I can't think of anything else that would "fix itself" while the engine is cold then break again when it warms up.

I'm still pretty new to the early A-bodies so any tips would really help! I'm getting ready to just drive her up to the car parts store and see if they can test the alt or just buy a new one and see what happens (but keep the receipt). In the mean while I'm charging up my spare battery to throw in the trunk ;)

By the way, it's a '66 barracuda 273 4bbl top end with 360 heads/bottom, all original wiring accept for the Mopar electronic orange-box ignition. I've had ZERO problems with the charging system so far.
 
Throw in a spare or if you have a Mopar buddy nearby swap one out to check if that is a fix
 
i agree with fishypete. my 73 did the same and replaced the regulator and have been goin since.
 
With these 40+ year old charging systems, it can be hard to tell what has been changed before you got the car.

We will assume the regulator is the original 2 wire type, and that your alternator has a single wire connected to a push on connector - as well as a large gauge wire bolted down on the output stud.

To full field the alternator for testing, you would remove the small (usually green) wire from the push on terminal on the alternator. the jumper wire goes from the terminal on the alternator where you removed the small wire to the output stud on the alternator. You do not jump the green wire to anything.

Doing that test will cause the alternator to produce it's maximum output. If you do not see more than 15v doing that test the alternator has a problem.

If you see 15v or more, then the alternator is capable of charging the battery. You may have a bad regulator or a wiring problem.

B.
 
I tried doing the full field test while measuring voltage across the battery and there was no increase, I also jumped the voltage regulator wires together with no change. It looks like my alternator is bad.
It is a single field with the post style alternator and the voltage regulator is the original solid state wire-in wire-out style.

I called a few places and they don't have it in stock so I'm thinking about ordering one from mancini's today. Could I run the 60A alternator with my factory harness without any problems? I'd like to have a little more juice if I have to replace it anyways.
 
The original voltage regulator was a coil/points type regulator. Replace it with a solid state one if you want to keep the electronic ignition module from failing.
 
Rock auto i bought two with shipping they were cheaper than one at my local parts store.AIRTEX / WELLS

1V1067
 
Went to Mancini's today and picked up a new alternator. Solved my problems :) They said they will be getting in the early style voltage regulators soon, just like the old black box solid state ones but with electronic guts.

Car is running at 12.5v at idle across the battery and about 13v with the revs up. Looks good! :)
 
If you want to run a 60 amp alt you should run a new 10 gauge wire from the alt to the starter motor. Then install a volt meter in the car.
By doing this you will get the 60 amp output to the battery without the added resistance of the smaller gauge factory wire and the firewall connector then running through the ammeter to power the car and then back through the firewall connector to the battery.
By not doing this it will be just a short while before the ammeter fails or the firewall connector melts.

The ammeter will then just show how much draw is on the system. Or you could move one wire on the back of the ammeter to the other post bypassing the ammeter so it won't show a discharge.

The reason for bypassing the ammeter is it can't handle 60 amps. When it fails the car won't run until you bypass the meter.
 
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