1971 does not charge

[johnr91122]

Hi everyone, I wonder if someone else has replaced their alternator on an early 911. Mine is a 71T. The alternator light is on all the time and the batteries do not charge. I measured the voltage and my charging system is not producing a high enough reading. The procedure to replace my alternator seems easy enough, but I am not sure if that is the remedy.

My understanding is that it could be the alternator or the voltage regulator. I also understand that the voltage regulator needs to be matched to the alternator. My inclination is to get the alternator tested. Is that possible? Do I just take it out and take it a shop?

Normally, I think I would just order a new voltage regulator and see if that cured the problem. If it did not, I would then simply replace the alternator. But with the need for the two components to be a matched set, this isn't so simple. I suppose I could just replace the two with a new matched set. Still, would be nice to know if the alternator is actually bad.

John

[Dick Shift]

early 911's like yours originally had alternators with an external voltage regulator as you know. Can't imagine that set up still in service. For the past 20+ years all I've seen available were alternators with internal regulators. To save money you could match your external regulator the same brand. If I have what you need I will send. If no ext. reg. You probably know the external is on the engine compartment fuse panel next to the CDI. If not then your alt. has been upgraded to a internal regulator. And you remove and test. I have found most places that test,
cant test 911 alternators because of no drive pulley. I put on a 944 alt. pulley and now can easily be tested. Hope this is of some help.

[T77911S]

call the local alt rebuild shop and ask them if they can test/rebuild it.
if they car, i would have it rebuilt if it is bad, maybe even if it is not since it is out.
ask if they can test the reg too.