Quote Originally Posted by JOATMON View Post
You're probably got the ammeter shunt resistor going into meltdown. The original '58 generator was about a 30 amp so the shunt was sized for it. When you're pegging the ammeter the shunt is getting extremely hot and may be the cause of your failures. You may want to try bypassing the ammeter by tying the two wires together with a small screw and nut, tighten it good and tape it up good. Then see if your alternator problems go away.
Joatmon, that's an interesting observation that just may be the problem. However, since the alternator is putting out >15 volts when the ammeter is pegged I'm not too inclined to believe that the resistor is the issue. And here's an update: Wife and I went for a cruse Saturday to Cave Creek which is about a 30 mile round trip and the ammeter was rock solid at 6 amps after it settled down after starting. Just like the last alternator the problem is intermittent. And speaking of intermittent take a look at another post that I'm going to post in a few minutes.