New Guy! . . with Polarity issue

[Aeroweld3033]

Hey everyone im new to the forum, this is my first post and first id like to say that this is by far the best forum ive seen yet so it looks like ill be sticking around for a while. .
Im not new to Triumphs ( I have a TR7 i restored myself and have worked on friend's Triumphs and Mgs aswell). I just bought a '73 GT6 MkIII on ebay. Its a beautiful car and seems like a great starter project, especially for the money i paid. My first obsticle on this project seems to be a polarity problem thats got me puzzled.

When i first got the car, it imidiately needed an alernator so i purchaced a reman. Becks-Arnley piece. The paperwork states its a neg. ground alternator. everything in the car is wired for pos. ground. it stated and ran for about 20 minutes under its own power ( however im currently moving and all my equipment is packed up so i didnt have a test meter to see if the alt. was actually charging the battery. )

After looking online i see several wiring diagrams that state the car should be neg. ground. im asuming someone changed it on my GT along the line. I would like to change it all back and I understand that this is not a huge project at all, actually quite easy. . however i also took out the starter to clean connections and sort of refurbish it. After bench testing the starter I see that the only time it moves, kicks, or shows any sign of power is under positive ground. It doesnt flinch with the neg as the ground. . . would this mean I either need to clean things a little further on the connections or need a new negative ground starter? i was told it should spin no matter what but it certainly is not. .

Any advice would be greatly appreciated!!!
- Charlie

 

[TR3driver]

Wow, that's a strange one. I've switched polarity on stock TR starters many times, and never had a problem.

Is it possible your car has one of the aftermarket "high performance" starters with permanent magnets? Otherwise I rather suspect it's just coincidence, perhaps you weren't getting a good connection in the negative ground configuration.

Oh, and your car should be negative ground. While positive ground alternators do exist, Triumph never used them.

 

[Aeroweld3033]

alright well thank you ! maybee ill take the starter out and try again, clean it up more . or find a new starter. . i dont think its aftermarket but there close to no indications on it to tell

 

[Geo Hahn]

Strange indeed. If in fact your car had been running as a positive ground you will want to take a look at any radio or other electronic accessories as these are usually specific in the polarity they require. The stuff normally on the car (e.g. starter motor, wiper motor) don't care.