12 Volt

[Will]

I have a friend that wants to switch his T over to 12V, Who sells a reliable 12v starter and alt.

[TXGOAT2]

No magic in 12 volts.

[speedytinc]

If you feel you must!
Admin jeff sells converted to 12V T starters. Its a PITA job. I have done a few also.

A model T generator will produce 12V. It dont know any better.
One must adjust the output to 1/2 for longevity purposes, 4-5 amps is plenty anyway.
That saves a few bucks, keeps a T motor looking like a T motor & avoids some common alt conversion failures.

[Moxie26]

Will ... It will cost him a hell of a lot less simply to replace battery cables with the proper gauge, clean and shine all electrical connections, use a quality 6 volt battery, and even more important to have the generator working as designed with the current, no pun intended, voltage regulator offered.... If the starter is filthy, cleaning and new carbon brushes, maybe in order along with sealed bearings. ... PLUS... LED bulbs will give a hell of a lot more light with less drain on the battery and generator.

[Jeff]

Just look at my website under 12v Starter conversions and you'll find a wealth of info and pics of horror stories of folks jamming 12v into 6v starters. Honestly, I try to talk folks OUT of converting their cars to 12v BEFORE they do it. If it's already done, then I do make 12v converted starters that work well and I must have sold over 100 of them at this point.... They're so popular I keep them in stock at all times. I've sold dozens on TBay.

Unless 6v batteries are wildly expensive or unobtainable, there are zero justifiable reasons to convert a 6v car to 12v. A well maintained 6v car will start and run just as well as a 12v car. Design considerations are different for each, and if properly met, there's no difference.

Keep in mind 6v cars require larger wire for the starter circuit so more power can be delivered to the starter. Who knows what 100 years of owners have done to their cars in the name of "improving" them...
If you want to run 12v accessories on 6v, there are DC-DC boost converters that do the job well. I have one on my car.
Want brighter headlights? Buy 6v LED headlight bulbs from Langs. Game changer.

12v cars require ALL electrical components to be converted to 12v. Yes, you can run your coils on 12v.
The generator will be under a higher load and will need to be adjusted for lower output or you'll reduce its life significantly,
The starter will need to be converted or eventually you'll destroy your ring gear and bendix.
All light bulbs will need to be replaced.
If you use an 12v alternator (or even a 6v alternator for that matter), the charge circuit wiring MUST be upgraded or you risk a car fire.

This is not an exhaustive list. There are other considerations.

As always, your mileage may vary.
Jeff