MTFCA Forum

can this be done when converting to 12 volts

Electrically speaking, I can't see any difference with your modification. All the field coils are still in series, which then feed the parallel connected brushes.

thank you , its just, that it makes it easier to me to convert to 12 volts this way

Lorenzo

it is no business of mine what you do, but as a long time T owner, both stem-winders and starter cars, I have never felt the need nor been convinced of the improvement that 12V brings. If you're being coached to do this, rethink it. If it is your decision, then have at it.

Yep! That's how you do it. Takes one heck of a hot soldering iron to get good connections. Its kinda of a headache, but it will be much nicer on your starter. I have lots of friends who have 12 volt system on their cars. They claim not to have issues with their bendix components. However I am staying with 6 volt. My car starts and works great. No reason to change.

Not sure what 12 volt devise you need to run or why ts necessary but have you looked into one of these DC 6V 5-11V to 12V 10A Step up Converter Regulator Boost Power Module Input voltage 3.6~30V,output ±3~±30V adjustable There are all kinds & brands this one is < $30
http://www.denontek.com.pk/index.php?ro ... uct_id=202

I have used ^ volts before ,but it was hard to start , coils where weak ,even with a rebuilt starter , -the coils work great on 12 volts, the 6 volts bat. here are hard to get and lasts 9 month if ever, up north in farm areas it might be better , i love to have 6 volts and be more original - i have converted 3 starters so far ---so far so good
Thank u all for input ....lorenzo

A properly running stock 6V T should not require conversion to 12V. If your T is not running properly as designed on 6V, chances are good that it won’t run properly on 12V. It is better to find the source of the reason it is not running properly before converting to 12V. I sold my 26 coupe to a friend in 1996 and he hauled it from Florida to his summer home in York, Maine. He had it for 5 years before passing away from cancer in 2001. When I bought it back from his widow for what I sold it to him for, I found that he had converted it to 12V. When I got it back to Florida, and got into the engine, I found that the bendix spring was unwound and bowed out. I posted pictures on the forum in about 2010. Ever since seeing that destroyed spring, I have been against converting from the original 6V system to 12V. I seriously hope you will reconsider. Just my opinion. Good luck. Jim Patrick.

If your magnito is not working consider using a distributor. I found that coils don't do well at higher RPM on DC.

When i rebuilt my engine[ coupe 26 ]i left the magnets to move oil and to keep the weight of the flywheel but removed the mag. coils ring ,. i use 12 volt bat. and CONVERTED my starter to 12 volts --i use a distributor, foot feed ,and find it to be a lot better ..,CONVERTING [look at picture on top] to 12 will not harm to the bendix spring or flywheel starter gear, i used to run coils but it as not as good as the distributor, if u like the old system --good use it ,but IMHO the ignition was not one of Henry best idea...Enzo

A starter car does not require 12 volts if everything has been rebuilt correctly. I do use '12 volt hot shots on my hand crank cars. It just makes them start easier.

I’m looking at what your doing but your diagram looks like you are moving 2 wires
When I convert my starters I cut one side of the in feed bar one side
Then at other end I separate the 2leads at the brushes lead and send one Side of coil back up to top coil the same as your top half of your diagram
So you don’t need to move a brush

I have been reluctant to respond to this post.
Cambin's (Cameron's) response promoted me to finally respond as well.
His reply is absolutely correct.
I was looking for a photo of how I do it this way, but have not found it yet.
Your original unmodified diagram is the correct method, not the modified diagram.

Respectfully
Terry

Please elaborate --Y---

I had a starting problem with My 6 volt 26 open express. it has always chugged and turned over slowly since I have owned it. But it got to turning over slower and slower and one day I started smelling electrical wire burning and it wouldn't turn over. Turns out the fix was simple the cure a little more work. The lock washer on the battery side of the starter switch bolt went flat losing its tension allowing the nut to loosen up. causing a poor connection and the wire & lug to get hot and burn the insulation and discolor them. further investigation discovered the battery to starter switch wire was a small gauge cable 12 volt wire and the original heavy duty cable was being used as a ground wire. adding about three feet of unneeded small gauge wire between the battery and starter switch. I cleaned up all the connections and cable lugs replaced the lock washers. tossed the 12 volt cable. swapped the heavy gauge cable from ground to hot side of the battery and built a new 10 inch ground wire out very heavy gauge wire. WoW what a difference instead of chug-----chug-----Chug-----Chug. it's now Chug-Chug-Chug-Chug a slight hesitation / slow down on compression stroke's but not much. it's 95 degree's and the oil is warm but hopefully it will still crank ok in the dead of winter but maybe slower. I wanted to see how 6 volt starting worked when all the connections were good and the cables the proper gauge and length of wire. does not wind up like My touring with 12 volts but I don't haft to worry about blowing a bindix either ? turns over fast enough to start the truck with no problem.

Hello Lorenzo,

As at least one person stated, electrically it is the same and that is true. What is not being factored in is the current draw, power, and heat.
Although I may not have accurate numbers, I have numbers that are in the ball park and will illustrate the problem.

A starter modified for 12 volts per your diagram will draw at least 150 amps and I feel that is on the low side while cranking the engine.
With the brushes wired per the original diagram that will be about 75 amps through each wire between the field coil and the brush holder.
With the brushes wired per your suggested change that would be 150 amps through the wire to the first brush holder, and
since there is unpredictable resistance between the first brush holder and the second, unpredictable currents on the first and second
brushes. This changes the power distribution from a balanced system as originally designed to and unbalanced system in addition to much
larger currents through the first wire.

I hope this helps. I may be able to expand on this more tomorrow evening if required or requested.

Respectively
Terry

Hi terry if I’m right though 6 volt draws heavy amps but 12 v won’t draw as much amps and 24 draws less again
Am I right in theory ?

Hi Lorenzo I’m going to try and explain so her goes
The first pic is of an in modified starter and as you see the input bar is connected to both sides to a coil
On the other side there are the brush leads joined in the middle by two coils but the eyelets are on one continuous lead

Part 2
I have marked in white where to cut on input bar and on brushes lead
On input bar I cut the left bar as marked on first pic
On second pic you will notice the left coil bar has a white mark on it that is the second detachment

Part 3
These are a diagram that should help under stand how it is done
The reason I’m lost with cutting and rerouting a brush lead don’t make sense as your not modifying any of the brush part you are simply taking one of the 2 joined coil leads off so they are separate
The separate coil is simply having a new heavy lead soldered to it and sent around to the cut of input coil bar

And finally this is what you should end up with

From the looks of those coils there is no question in my mind why they did not work on 6V. I hope these didn't go back into a hosing like that.

15 million plus Model Ts were made. All that were built with electrical systems were 6 volt. I could care less what you do with your car's electrical system, but if your T isn't running as it's supposed to on 6 volts (and the magneto), there is a problem. My approach would be to find it. If it's a slow crank, a voltage drop test should be conducted (pun intended) at every connection in the starter circuit - including ground. If the battery is good and the connections are good, there is a problem in the starter or in the transmission clutch.