12 volt conversion?

[Chris Luecht]

I have a 54 Manhattan with Supercharger and was wondering how I could tell if the car was converted to a 12 volt system.  The engine will not start, even with a fully charged, brand new 6 volt battery, but cranks over just fine with a 12 volt.  I do notice that the ignition coil seems to be different than any other one that I have seen on a KF car and there also seems to be a resistor of some sort that doesn't look original.  How can I be sure if it was converted, or if it is just some other problem not allowing the 6 volt battery to work properly?  Thanks in advance for all your help,
Best regards,
Chris

[Gordie]

Hi Chris,  I suspect that it is a typical six volt car that is hard to start.  You need to make sure that you have the proper 6 volt battery cables and ground cables and that they are clean and getting a good connection at all  of the ends.  There are various qualities of batteries and you want to make sure that you have the most powerful one to fit your car.  Check your electrical parts like the generator, voltage regulator, and coil etc to see if they are marked 12 volt.  Most 12 volt conversions change the generator to an alternator so that would be a give away if you have an alternator.  Good luck!!

[Fid]

Also check the tag on the starter for a number.  A Delco-Remy starter should have a number similar to 110xxx
Get that number and post it on here and I'll look it up for you.
Also, as Gordie points out, six volt battery cables were much thicker / heavier gauge than 12 volt.  Often times, in the late 60s - today, if an original cable corroded away (and they often did) it may have been replaced using a modern generic one from an auto parts store, it likely was designed for a 12 volt system so it may not be able to carry the current required to spin a 6 volt starter.  KF used 1 gauge cables and you can get authentic looking, correct gauge, cables from http://www.antiqueautobattery.com/