12 volts to a T starter

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Model T Ford Forum: Forum 2015: 12 volts to a T starter
Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Friday, June 19, 2015 - 10:01 pm:

We are thinking about putting a starter in our 19 T
It has everything needed- correct hogs head, ring gear, etc.
Since I use a 12 volt battery for starting I was wondering if it is OK use use 12 volts on the starter,
A lot of people on the Ford barn say it is OK but I am wondering if the T guys have any experience with thiis


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Friday, June 19, 2015 - 10:10 pm:

No it is not Ok. There are only about 20 (or less) Model T "owners" that post in the Model T section on Fordbarn. (The A and V8 sections are great)

http://www.mtfca.com/discus/messages/506218/550715.html?1434751293


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Bowker, Ramona, CA on Friday, June 19, 2015 - 10:25 pm:

The T starter MUST be modified to operate reliably on 12V. The instructions are available on the forum or send it to one of the T electrical guys.
Basically the two parallel stator windings have to be wired in series, actually doing it with heavy gauge wire is fun....


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Friday, June 19, 2015 - 11:10 pm:

Fred I am the exception as my Coupe was stock standard until an elderly owner is 2009 put a 12v battery in and 12v bulbs. He rallied several times over the years, I purchased it in Feb this yr and it gets a lot of use, started via the starter approx 20 times a week. It has never been modified or broke a bendix and is still going fine. There will be heaps of people tell you it is risky and will break a bendix on a regular basis. Mine might do it tomorrow (might break a crankshaft to) but 6 yrs later & still going fine. We have a model T railcar 1.5hrs from here and a heap of volunteers operate it, it used to break a bendix often until a local sparkie used a bendix spring to reduce the grunt going into the starter and it has never broke one since. I suggest you look for a method of modifying it but I'm not going to on mine until it fails. I have a high compression head, maybe that is a positive making the starter crank harder?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Friday, June 19, 2015 - 11:12 pm:

Sorry but I must disagree. 12 volts will work just fine if you connect the battery with 6 ft long modern skinny 12 volt cables. If you just swap the battery for 12 volts you will slam the bendix and it will die in short order. The generator can be reset to put out about 5 amps or so at 12 volts. It will put out more but it will get very hot and also die quickly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Friday, June 19, 2015 - 11:15 pm:

If you like, Daryl Becker will sell you a modern 12 volt starter for $165 or so.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Walt Berdan, Bellevue, WA on Saturday, June 20, 2015 - 12:07 am:

A rewired T starter or custom starter like Daryl provides is likely the safest option. I use 12 volts on my speedster with a stock starter and have bent a couple bendix springs over the last 20 years when I neglected to retard the spark. So far no broken bendix issues. Of course that could all change tomorrow but until then, I'm happy with 12 volts on the speedster. I must say thought that a good 6 volt battery and starter work just fine on a stock car if the connections are clean and the proper (at least 1 gauge) cables are used. My 26 coupe with Z head starts just fine on 6 volts now that I upgraded the cables and cleaned all connections.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les VonNordheim on Saturday, June 20, 2015 - 01:08 am:

I'm in the same boat as Kevin Weeds. Except my car has been using 12 volts for over 15 years and no failures yet. I am very careful on retarding the spark before starting. No issues yet!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Will Copeland - Melbourne Florida on Saturday, June 20, 2015 - 07:02 am:

Iv had a Becker 12 volt starter for many years, Never a problem


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Georgetown TX on Saturday, June 20, 2015 - 08:50 am:

I've always had 12 volts on the starter. No problems ever. Ron Patterson explored how much torque a Model T starter made on 12 volts, it is a paltry 20 ft - pounds or less. Yes it is more torque than on 6 volts, but it is still rather insignificant.

The thing that breaks a bendix is age or forgetting to retard the spark lever.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Saturday, June 20, 2015 - 09:43 am:

The chart is below.

A 12v battery doubles the torque on the Bendix, the starter shaft, the Bendix spring, and other parts of the Bendix, the Bendix gear and the ring gear on the flywheel.






Bendix spring result on 12v




Do as you wish for your stock 6v starter and generator....just be prepared for real time maintenance checks, and / or repairs.

On a tour last year, fellow ran out of oil, found dripping under the T. We inspected and the Bendix cover was askew, letting oil flow out. Asked about his battery...answer was its a 12v. That is what knocked loose the cover, dented side, the Bendix spring had twisted oversize and caused the oil lost.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Saturday, June 20, 2015 - 10:42 am:

My findings differ but I don't have a pretty graph nor do I want to start an argument. :-)

I will mention this: A 6v starter with a modern rebuild that only turns 3000-3500rpm (unloaded) is under considerable drag with lost torque and a higher current draw. A reason many respond by using 12v.

Yes, I know. The numbers support the specs from 1919 but that's not applicable with todays methods or parts.

There's no support for going to 12v for a 6v starter unless the entire car is being converted for some other reason. (Lights, no mag, racer, etc.)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Saturday, June 20, 2015 - 02:52 pm:

If you look closely at the chart above Chuck Brant and I measured and plotted back in 2000 you will see that operating a standard 6 volt Model T starter on 12 volts results in a 60% torque increase.
The dc starting motor itself is very robust and will tolerate much, but the items being driven (armature shaft, Bendix & flywheel ring gear) suffer a great deal.
And if you forget to retard the spark all hell breaks loose.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Saturday, June 20, 2015 - 05:00 pm:

I'm in pretty fast company here, so I probably shouldn't even enter this discussion, however,..........

I understand the increased starter motor torque with 12 volts vs. 6 volts. But I think this is a pretty complex comparison, and I'm not even sure I can explain what I'm thinking, but here goes,.....

To my uneducated way of thinking, the biggest problem here is the "shock" to the bendix when the starter pinion slams into the flywheel ring gear. I think added torque is just part of the problem. It takes a couple revolutions of the starter shaft to crank the pinion into the ring gear. During those couple revolutions, the shaft is accelerating from dead stop to whatever rpm it reaches when it slams into the ring gear and the "shock" occurs. What I'm wondering is what that rpm has increased to at time of "shock" with more torque from the 12 volts as compared what the rpm has increased to with 6 volts. After all, the 'shock" is a product of torque "AND" speed (rpm) and I would think that the additional torque with 12 volts would mean greater shaft acceleration and greater rpm at time of impact.

Yeah,....I knew I shouldn't have gotten into this, 'cause I jut barely understand what I just said,...ha,ha,.....harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Skip Lane Melbourne, FL on Saturday, June 20, 2015 - 05:10 pm:

How can one tell if starter is 6 or 12 volt?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Woods, Richmond, Texas on Saturday, June 20, 2015 - 05:25 pm:

Since Ford didn't make a 12 volt starter for a T, if it is an original Ford T starter, chances are in the 90th percentile that the starter is still six volts and hasn't been rewired for 12 volts (which is possible). Most currently available 12 volt starters, like L.D. Becker sold, use a Delco starter case with a custom armature shaft and aluminum starter to hogshead mounting plate. Easy to tell the difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Saturday, June 20, 2015 - 07:07 pm:

A few answers --

I made the question as simple as possible to avoid confusion so here are some answers to the questions.

My 19 did not have a starter but I have a few spare 12 volt batteries so I used one when I started the T and switched to the mag once it was running. E
I also added 12 volt LED stop lights and like the ability to plug my cell and GPS into 12 volts.

Recently we put a 26 motor in the T and I found it harder to crank because it is significantly tighter.
My son talked me into installing a starter - no generator - and now I am trying to decide if I should add a 6 volt battery for the starter or just use the 12 volt battery.
Since I do not have a generator I will just charge what ever batteries I have.

An added concern is that the mag on the new motor seems to be weak so I might have to run on the 12 volt battery.

So the 12 volt battery will stay.
The question is - do I need to add a 6 volt battery for the starter?



Another question. If I add more batteries will I be required to register the vehicle as a an electric hybrid?


Top of pagePrevious messageNext messageBottom of page Link to this message  By kep on Sunday, June 21, 2015 - 03:29 am:

No you will not have to register it as an electric hybrid.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Sunday, June 21, 2015 - 07:52 am:

Royce has had some good info and techniques on reducing 12v current to the starter (making it easier on the bendix). You might want to PM him and ask how they did it. Easier and cheaper fix than converting the starter's fields to series set-up. Yes, I have successfully converted Model T starters to 12v series fields. Just loads of fun! To be honest, at $165 Daryl Becker can do mine next time if needed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Sunday, June 21, 2015 - 09:03 am:

Royce

Does age and forgetting things go together?


If I read the replies correctly it is OK to apply 12 volts to the starter as long as the bendix is in good condition and I remember to retard the timing. I will get a new spring, key before beginning to use it with 12 Volts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George Andreasen on Sunday, June 21, 2015 - 09:34 am:

There IS a solution..........buy an 8 volt battery. Yes, they make such a critter, it's not difficult to locate and they come in the same case sizes as 6 volters. Just go to a battery distributor such as Interstate and have the order you one. The cost will be the same as a 6 or 12 volt, your generator will keep it charged, it won't harm the starter and give you plenty of spark for starting. Any ordinary 6 volt battery charger will keep it fresh when the car is stored.

The 8 volt battery was developed many years ago when people complained about the slow cranking of a 6 volt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Sunday, June 21, 2015 - 10:20 am:

When I bought my '15 Touring, one of the conditions of the sale was that the seller, who was a Model T mechanic, equip the car with a 12-volt electrical system including a 12-volt self-starter (and, of course, charge me for his parts and labor).

That was five years ago, and I've never had a problem with the starter. _My recent misadventure with taking the car apart to get at the starter to dismount and have it rebuilt was not the fault of the starter—it was perfectly fine—but the fault of a stupid dead battery.

When I had the starter out, it was easy to inspect the flywheel and its ring-gear with a flashlight, and after five years of use, there was no visible damage. _Of course, the bendix was also easy to inspect and there was no damage there, either. _That would cause me to suspect that the 12-volt version of the Model T self-starter is a pretty good piece of equipment. _Your mileage may vary, but in the case of my car, there's no problem I can see.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Weeds on Sunday, June 21, 2015 - 06:51 pm:

Fred D, simple answer is yes, in my case & others it has been fine. I purchased a speedster last weekend which I haven't tried to fire up yet due to the foot of snow, it runs 6v. I have a new 6v battery but if it winds too slow AND is a stubborn cranker a 12v battery will be going in it as it sits.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Willie K Cordes on Sunday, June 21, 2015 - 11:56 pm:

Ted Dumas had about the correct solution. If you leave the old large 6 volt starter wiring, the starter will slam in very hard. The key to reducing the current is wire size. Use the small 12 volt type wire with a 12 volt starter. That extra length of wire that Ted suggested would also help.
The electronic formula for current in a circuit is. Current=Voltage divided by Resistance. That means you will have less current with the smaller diameter as there will be more resistance to the current.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Monday, June 22, 2015 - 07:51 am:

I'm curious about the ones who put in 12 volt to speed up cranking. How fast do you hand crank it and how long do you have to crank it that speed makes a difference?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Glen Chaffin on Thursday, June 25, 2015 - 11:42 pm:

The last time I checked electrical power is equal to E squared over R. Where E is the applied voltage and R is the resistance. The resistance does not change so when you double the voltage the power increases by four times. So when you increase the voltage to the starter from 6 Volts to 12 Volts you increase the cranking power by four. This is what kills the Bendix. likewise a starter rewired for 12 volts has the same cranking power as a 6 volt starter because you double the resistance by putting the windings in series instead of parallel and the cranking power remains the same..


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Georgetown TX on Friday, June 26, 2015 - 06:54 am:

Doug,

Cranking speed doesn't matter. A T will easily start on BATT no matter how slow you crank it.

I've always used 12V battery cables with 12V batteries and never had a bendix problem or a damaged starter or gear.

https://www.youtube.com/watch?v=RhEnNzv6LBM


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells, Hamilton Ontario on Friday, June 26, 2015 - 07:28 am:

Why not just keep the correct 6 volt setup? It starts the car instantly if all else is working right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chuck Lebeda, Humboldt, SD on Friday, June 26, 2015 - 08:59 am:

Years ago I sold a 1923 touring to a ‘newbie’. When we went out to start the 6v system. It turned over slow. Fellow says your battery is almost dead. I said “NO” that’s just a Model T. It started.

To each is own!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Glen Chaffin on Friday, June 26, 2015 - 08:56 pm:

Putting a resistor or 12 volt cables in series with the starter to reduce the voltage does not work. When you apply 12 volts to a starter the starter sees 12 volts immediately and starts to turn. The voltage does not drop until the motor is turning and drawing current. At that point it is too late, the damage has already been done. I have told you this many times but no one listens. But that is good for me. I just sell more new Bendix.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tony Bowker, Ramona, CA on Saturday, June 27, 2015 - 01:52 am:

This is not a simple problem. There are many elements involved and if we apply strict DC motor theory to the automotive starter, it will fail.... Of course we all know they do work but we also know they are on the edge of failing, slightly low battery, poor connection and its all over.
The typical Model T system has a battery, two cables and a switch, a series electric motor with two field coils in parallel and a chassis return.
If we assign vales to each of these terms, we can estimate the effects of any changes.

From previous work I assigned values as follows:
Resistance of the switch and cable - 0.01 ohm
Resistance of each field coil - 0.02 ohm
Resistance of the rotor - 0.01 ohm
Resistance of the ground return - 0.005 ohms

These values were then plugged into a spread sheet with the following results



The results of the unmodified 6 volt system looks reasonable and inrush of 171 amps, power dissipation of 588 watts and quite a bit of power (heat) in the switch.
Now look what happens when we increase the voltage to 12 volts with the unmodified starter, the power rises by a factor of four and the switch gets REALLY hot...

Now when we apply 12 volts to the modified starter, the two file coils in series rather than parallel, the power still rises but the inrush current is virtually unchanged, and the power still rises, but not as much as the unmodified case. The starter will get hot and is easily abused but voltage losses are much reduced for a much more consistent operation. I doubt this evenings work will change any minds on the subject, but I really do NOT recommend using the unmodified starter (and generator) on 12 volt systems.

(Message edited by Tony_bowker on June 27, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Saturday, June 27, 2015 - 08:28 pm:

This subject has been discussed some many times. So here it goes for me anyway. I have a totally stock 1925. Every part of the electrical system on the car is either NOS, or rebuilt to original specs. I used a 6 volt battery that is housed in an original Ford battery box, and it spins that engine over like it has a 12 volt battery, BUT IT DOES NOT.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Sunday, June 28, 2015 - 12:51 am:

Royce, that was what I was referring to. It shouldn't matter how fast you crank the motor. They should start on the first or second revolution.


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