Working on our 33 Ford...didn't run when we got it...I understand the concept of Negative/Positive Ground...however How does one figure out which applies...

I've hooked up a new 6V batt Negative Ground...and got the truck to run...hard to believe that the engine could run backwards...but some have left me with that impression?

Anyone have any thoughts...? or as long as it runs leave it alone and move on to the next problem?

 

Does your ammeter show a negative charge when running about 1500 rpm's?

If you're hooked up neg grnd and the meter shows discharge, you'd better turn it around and go with positive grnd.

Generally, I'd say if it is still 6V it's probably been left positive grnd. Most guys only change to neg grnd when they switch to 12V.