I have read and understood all the discussion on how to do the conversion but I either didn't see it or missed it regarding the starter. The starter is a dc motor and I thought if you reverse the voltage on a dc motor it will spin backwards.  So the 12 volts wont hurt it but going from positive ground 6 volts to negative ground 12 volts.......wont the starter turn backwards?   What did I miss?

The starter will not turn backwards.  It is not polarity sensitive.  I had a 6 volt starter in a flathead that was converted to 12V.  All it does is make the starter turn over faster.  You probably will burn it out if you do a lot of "grinding" with the starter, otherwise it will work very well.

I don't know all the ins and outs of electrical theory, but the starter will work ok.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Did Thunderbird have positive ground?  Joe 

Located in Harford County Maryland 

My 55 bird went from 6v pos to 12v neg 20 years ago. The way the motors are wound, they don’t care about pos/neg ground. Intermittent motors, seats, windows, starter, work fine. Horns and relays work fine. Just don’t overuse them on a continuous basis.

The heater motor will need changing. Coil, and gauges the right resistors or voltage regulators. That info is on here. Probably the o/d solenoid, but there’s mixed opinions on that. I changed mine, they weren’t that pricey back then. Starter relay, because you need the second small terminal for 12 volts to the coil on the start position.

The clock and the radio need more care and attention. My radio was replaced when I bought the car (12 volt neg with some sort of adapter) and the clock never worked, so I don’t have any info there.

There’s a couple fairly current discussions on the Ford Barn about this if the search function here doesn’t provide your answers.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Sometime around 1967 or so I converted my Tbird to 12V neg ground. I got a 12 volt starter and a 12 volt generator to complete the conversion. The 12 volt starter is still sitting on my garage floor waiting
for the day the 6 volt starter fails. 6 volt starter work great when fed 12 volts. Pete