<VV> Voltage Failure Heat-Related

[goofyroo at excite.com]

A few weeks back I asked for help with a voltage drop in my '63 with '70s-style alternator.  Many thanks to those of you who replied.

The problem hasn't gone away, despite a lot of troubleshooting.  In fact, it's gotten worse!

At idle the alternator produces 14.6 volts, measured at the alt or the battery posts.  In the driveway, raising the RPM produces a very slight rise in voltage.

But the car will only go a few blocks in the heat until voltage trails off to the point it will no longer power the ignition.  The voltage drop also increases with RPM.

Here's a list of things I've replaced:

 - internal regulator
 - alternator
 - battery
 - slotted belt
 - new wrapped belt (some temporary improvement)
 - spring-loaded pulley (some temporary improvement)

I've cleaned the terminals at the battery and starter, where the alt wire links up to the battery cable leading to the trunk-mounted battery.  Also checked the battery and engine grounds, and jumpered around the engine ground as an experiment - no change.

I did super-tighten the belt as an experiment and got improvement, but couldn't leave it that way out of concern for the blower bearing.

Obviously I've missed something.  Heat is a definite factor - the car drives fine in the winter months.

I know people run Corvairs with modern alternators all the time and don't have this problem.  I'm lost as to what is wrong with this one.

(I've asked for help at AirVairs, so some of you may have seen this post before.)

Any ideas, please?

Michael Smith
Dallas

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