Please Help!! 171 911T Alternator/Regulator Issue
 

I have a 1971 911T that has an alternator and external regulator. I believe the alternator is a Reman. The sticker on the housing is completely faded, but it looks exactly like the Reman. The external regulator part number is 911.603.901.00. The system isn't charging the battery. I tested the system and took voltage checks and narrowed it down to either a bad alternator or regulator. I'd like to replace this system with an alternator that has an internal regulator.

Questions:
1. What alternator part number do I use?
2. How do I install the electrical to bypass the external regulator?

The original regulator is still installed in my 70T. I've had the alternator rebuilt only once and that as a precaution. I'm good with the external regulator. Why? Don't have to remove the alternator to replace. If it were me, I would remove the alternator and take it to a shop or your
FLAPS and get it checked out as a first step. If the alternator is bad get it rebuilt. Saves a good bit of money. Lots of shops do this. It ain't rocket science.

To go to the internal regulator you need to get fan housing with the 19 mm back spacer. 75 on, because yours has a 25 mm back spacing making the alternator and fan stick out from the housing.
Bruce

http://forums.pelicanparts.com/uploa...1441153201.jpg
http://forums.pelicanparts.com/uploa...1441153213.jpg

alternator upgrade to IR in early housing
 

new valeo IR alternators are available on e-bay to fit the early "105" housing - got mine from bnr

check this - http://forums.pelicanparts.com/porsche-911-technical-forum/537302-alternator-conversion-question.html#post5496545
.

I've always been a fan of the externally regulated charging set up. Why? External VR is easy to swap out (they are cheap to buy) and aren't subjected to the heat of the internally regulated versions.

If you're not charging, it's not likely because of your VR (they tend to fail by no longer regulating the voltage, resulting in high voltages to the battery, boiling it and causing a big acid filled mess) but a failed alternator. Take it out (not a hard job at all) and send it out to be rebuilt.

Just my $.02

If your VR is the mechanical type and still has radio noise suppression caps on the terminals, try removing those and see if it starts charging. Good chance the caps have gone bad in the last 40 years, and you're probably not listening to the radio anyway...

Not to hijack, but what is the best replacement regulator to use? I have the original mechanical in my '71, which works fine for now.

I would like to replace it when I upgrade my motor this winter. BTW, how do I know what the brand of my new alternator is, ('78 SC)? With out removing it from the housing?

Take vr and alternator to the shop they can test the system. Huco? Make an adjustable voltage regulator.