Alternator Install Question
 

1974 Porsche 914 1.7 dual carbs all other stock. I recently pull the engine and trans to redo clutch, gaskets and other maintenance items including a new/rebuilt alternator. I reinstalled the engine and went to connect the battery leads and quickly the battery arced badly until I pulled the big red wire that comes from the alternator off the of the starter. Car runs fine, but of course the alternator is not charging anything now.

Is it possible the alternator is bad and grounding improperly causing the arcing? Any thoughts anyone. I am on way to have the new alternator tested, but was wondering if I have done something wrong somewhere. I have the big red wire connected to B+ on the alternator.

Also, does anyone know of a place on can get a new alternator wiring harness to eliminate this potential issue as it is rather crunchy?

Thanks in advance.

By the way, a lot worse changing the alternator in the car than out!!!

pardon me, 1973

after some further checking and searching, it may be I need to trim my B+ bolts. They are too long and maybe arcing across to the rear shield and causing positive to jump to ground. Probably going to cost me an alternator.

Check all the wire from alternator to Starter to see if there was a bare piece of wire somewhere grounding out. Anyway, have ordered a new alternator. Does anyone know how to do a bench test and no one knows how to test these out of the car?

Generally the order of installation is to hook up the alt, regulator, wires and THEN the battery. The Haynes manual has instructions on how to remove and install but it has been many years since I did one on a 914. You must hook up all the connections correctly for sure. The one in my F350 was done this way and I learned back in 1963 to follow the manual's instructions!
For testing the alternator, any good auto parts shop should have a tester that can spin it and also put a load on it although many places in CA and other states now don't do that as the state sez that is "repair"?! So I'd say find an auto electrical place and pay $20 or so to have it tested.

alternator install
 

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Be sure to see the part about shortening the screws on the terminals. When I replaced my alternator, I had to shorten both terminals. Also, check each lead to the case ground with an ohm meter... they should read infinity except for the ground wire lead, which I believe is green. When you install the back case it sometimes hits the leads. BE SURE OF THIS, OR YOU WILL HAVE A SHORT AS YOU DESCRIBED.
John