I have acquired the family 1921 model t chassis and I am marrying a 1922 rear body on. I am converting to 12 volt system and have heard there is a bendix spring weakness using stock bendix is there a 12 volt spring available or is the stock one OK?
My 26 came with a 12v conversion, it works great. Reading this forum I've decided to carry a spare bendix, bolts and tabs just incase. You can change it out in short order if needed.
Jack Gates: I will say it again and keep saying it until people shoot me. I am always glad to hear locals tell me they are going to change to 12 volts because I carry a large stock of BENDIXS. I know that sooner or later they will be at my shop replacing their broken bendix. Keep going 12 volters I can always use the sales. I sent 25 bendixes to Germany alone, I wonder why?
By the way I am no longer shipping bendixes with springs, the 12 volters have run me out of springs and I havn't stocked up again on springs.
I think the most important thing about using a Model T starter is to be sure the parking brake is in either neutral or park position BEFORE using the starter. The starter bendix hits the flywheel quite hard and if the car is in gear, the flywheel won't turn. Of course if you use 12 volts it will hit even harder. There is danger not only of breaking the spring, but actually bending the starter shaft. There is no reason to use 12 volts unless you have an after market ignition system. Six volts works just fine for everything in the Model T electrical system.
Jack -- Rather than change the spring, just have your starter re-wired to work correctly on 12 volts. Ken Kopsky, who posts here, can do that for you, and so can many others.
Jack, Take the warnings about starter bendixs very seriously!!! You cannot convert a T to 12 volts without bendix failure UNLESS you change out the starter motor to one designed specifically for 12 volts. It isn't the 12 volt battery that spins a bendix so fast that it fails; it is the stock 6 volt starter motor that is designed for 6 or possibly 8 volts and NO more!!! If 12 volts is applied to a 6 volt starter, it will spin roughly, twice as fast; more that the bendix can handle.
Trust me and others, like Dave Huson, and take this from me personally. I tried replacing the 6 volt battery, decades ago, in my Grandfather's 27 coupe because the mag was no good and the engine wasn't tuned well enough to crank on 6 volts, by just replacing the 6 volt battery with a 12 volt. It worked for a while, but because the engine wasn't tuned good enough to start with just a 'bump' of the starter button; much less hand crank on battery, I found myself having to hold the starter button until the starter motor made the engine turn multiple revolutions.
One night when engaging the starter too long, the end of the bendix on the end of the starter motor shaft, loosened and shot clear off the end of the starter motor shaft; forcing the bendix cover attached to the transmission cover (hogshead) to explode off the transmission cover and damaging the cover and cover attachment screws. It also twisted and stretched the steel bendix spring, just like it was made from aluminum.
It was a lesson I'll always remember and never forget. Moral is: if you think you must have 12 volts; make sure you change the starter motor for one designed for 12 volts, NOT just change the battery to 12 volts!!! If a 12 volt starter isn't used, you'll regret the consequences, and by the way, there is no such thing as a 12 volt bendix. A stock 6 volt T bendix will work just fine as long as a 12 volt starter is used.
"You cannot convert a T to 12 volts without bendix failure UNLESS you change out the starter motor to one designed specifically for 12 volts.
Terry -- Please see my post from 8 minutes before yours. It is not necessary to "change out the starter." The Model T starter can be re-wired to work properly with 12 volts.
With a 12 volt battery, you can use a 6 ft. long 12 volt cable between the battery and the starter switch or battery and ground or both. On my 27 I use the 12 volt cable on the negative side, and it works fine. On my 24 I needed to use long cables on both the positive and negative cable positions. I have had good results and no bendix damage. Before the starter starts to turn there is no back emf so you get an appreciable voltage drop when the bendix starts to engage.
Royce's father showed me this technique about 20 years ago.
Mike, I should have stated my post differently. I meant that you could and should use a starter converted or designed for 12 volts, regardless of whether it was a converted T starter or one like L.D. Becker used to convert. Yes, Ron Patterson was the first one in recent years that have converted the T starter to 12 volts. Ken Kopsky has done it as well as others. My point was; you can't expect a T bendix to survive with a 6 volt starter operating on 12 volts unless you make other changes other than just changing the battery to 12 volts.
We have several T's operating with 12 volts to an unmodified starter using long, 2 guage battery cables. No bendix spring, flywheel or starter problems ever.
Royce, How long do your cables have to be not to blow the bendix off a 6 volt starter? I trying to help a guy without a lot or resources, keep his '25 coupe on the road. The magneto is trashed and gone, so he is running his coils on a spare 12 volt battery. Would be nice if he can convert his whole car to 12 volt and just have one battery. Would also save me the hassle of having to convert a starter to 12 volt for him.
Something to try. Everything from my '30 Town Sedan to my '17 power unit is on 6 volt - with one exception. My '27 T/IHC mower combination would not crank on 6 volt - simply wasn't enough to spin her. I put a 12 volt on and, after a suggestion from Royce, the extra long cables. She turned no problem. She has no generator (there's a governor instead), so there was nothing left to change over and all was well - until she went through her first Bendix spring. Put a new one in and figured this was how it was going to be - price I'd have to pay. I was at Lang's picking up parts about a month ago and I mentioned to Don that I'd probably be a frequent flyer on Bendix springs now. He suggested putting in an 8-volt battery - less stress on the system, but enhanced cranking power. I went to Tractor Supply (about the only place around here that sells an 8-volt) and so far, so good. I went back to the standard cabling (she's so small, there wasn't a lot of place to coil and stuff the longer cables and with the reduction in voltage from 12 to 8, it no longer seemed necessary). Now, I cannot say whether you'd have to convert your cutout and lightbulbs if you have a generator and you crank on an 8, but am sure someone on here could answer that. The $8.50 on Bendix springs didn't bother me as much as the pulling and reinstalling of the cover - an annoyance I could do without. If you're hesitant on the potential impacts of the 12 volt, try an 8.
I have to wonder how many cars there are out there that have been converted to 12v simply because the owner "Had always heard you needed to" rather than any real problem? Then I wonder how many have been converted to 12v as a "Band aid" to cover the real problem? Just wondering.....
Just run the car/coils on 6V. It will run fine. Done it for years. You do not HAVE to run coils on 12V. The average T driver wouldn't notice the difference.
I use 12 volts because batteries are more readily available and fresh. My 1943 Farmall M also now uses a 12 volt battery. I use long 12 volt cables as I described above.
The discussion on 12 volt batteries is somewhat like that of E-Timers. Those that like 12 volts have good results and are happy with 12 volt batteries. Those that that don't like 12 volts think it will damage your bendix and 6 volts is the only way to go.
Jerry, it's not my car! The car doesn't run worth a hoot on 6 volts. It runs a whole lot better on 12 volts. The guy wants to go one way or the other. The cheapest way for him to go would be the 2 gauge cable. I just need to know how many feet it will take running from the solenoid switch to the starter. or do I run it from the battery to the solenoid?
For the record, my OWN car is 6 volts. Yes it is a band-aid, but not everyone has the resources to spend fixing a sick or absent magneto. If this will work for the time being, at least it gets him back on the road.
Run a 6 ft cable from the battery to the solenoid. If that doesn't do it use a 6 ft ground cable also as described in my earlier posts.
Thanks guys I found my local alternator rebuilder is able to change my starter I bought from Don to 12 volts by changing from series to parallel or vice a versa what ever works. Thanks again Jack
Here is what works: from series-parallel to full series.
Ron the Coilman
I use 12 volts because I couldn't find a 6 volt air conditioner and oil pump. I have a Becker 12 volt starter.
Jack, from my view point you make the decision but here is my experience in converting 6 to 12V. I made the change 20 tears ago and promptly broke 3 Bendix spring in the following time period. While on tour later I met a fellow that had the same experience but showed me his solution to the problem. He had inserted a old bendix spring, in line, to the 12v power line that feeds the starter. It drops the voltage to 9v and in his case it "cured" the problem. I did the same and have never had a broken bendix spring problem since. Call it luck, black magic, story telling or what ever....it is as it is....
Be sure to keep the spark lever up when starting.
Ron the Coilman
Ron the Coilman