MTFCA Forum

Good afternoon ,
I was just finishing up the last of the wiring and then ,, woops .
Appears the contact had been previously epoxied .
That would explain the stakon connector .

Il order a new magneto tower but I’m unsure of how to determine if the contactor is the correct height .
If not long enough then no voltage ,, but if too long I don’t want to damage the coil .

Can anyone provide some guidance on fit up ?

Thanks , Vince

I believe the contact pin is spring loaded so it does not require trimming or adjustment.

There should be a solder spot about the size of a dime at the top of the magneto coil. If the magneto coils are not broken somewhere on the magneto ring, that spot should be grounded through the coils to the opposite end of the coils. Take a ohm meter and test for ground on that solder plug inside the hogs had at the top of the coil ring. Then install the terminal at the top and test. If you test for a ground from the hogs head and the wire terminal on the contact, you should be just fine. Only way to be sure the magneto is working is to start up the engine and test the voltage at the top. If the magneto is working, and you are running on magneto, the voltage go up with the rpm of the engine.
Norm

Helps to check the length of that spring loaded reproduction mag contact, as it differs from Ford original coil spring contact.

Some solder pads on the field coil ring are tall, and the long point on the reproduction may be too long and need trimming . Check first that the mag contact base seats fully before forcing the part on the transmission cover.




In this case the spring loaded point was too long.

I'm trying to bring a 1920 T back to life.

I have this similar problem. The engine dies on switching to MAG. I pulled the magneto post and it was covered in fibers. Once cleaned, it was a little quarter inch long needle-like spring as pictured above. And the T suppliers advertise posts that look much longer. The engine still dies on switching to MAG.

"In this case the spring loaded point was too long."

How do you determine what length to cut the new replacement magneto post?

Deperdussin1910..... Sounds like your magneto contact is okay but your magnets have to be recharged. .... Doesn't need engine dismantling, can be done in car with care.

Deperdussin1910 wrote: ↑

Fri Aug 15, 2025 8:32 am

I'm trying to bring a 1920 T back to life.

I have this similar problem. The engine dies on switching to MAG. I pulled the magneto post and it was covered in fibers. Once cleaned, it was a little quarter inch long needle-like spring as pictured above. And the T suppliers advertise posts that look much longer. The engine still dies on switching to MAG.

"In this case the spring loaded point was too long."

How do you determine what length to cut the new replacement magneto post?

Take a look at what Norman Kling wrote above and check for continuity. Have your magnets been recharged? Is the coil ring good? Not really enough information on why the car dies on magneto.

Just remember, the magneto puts out AC voltage. Make sure your test equipment is set for AC voltage between 0 and 10 to check idle voltage which should be around 6 to 8 volts AC, ... Mid-throttle engine speed should give you 25 volts AC.

Thank you for the replies. I found the following YouTube clip:

https://youtu.be/Lz4MlgH8K2U?si=pxuw68vwr4n9IMik

Are they using a battery changer? Or, are they connecting to the car battery?

Your engine won't run on MAG. That in no way means the Magneto is for certain non-functioning (it may be, but you have provided no information one way or the other).

it could be:

a bad switch?
incorrect wiring?
shorted contact?
open contact?
shorted/grounded mag coil?
open mag coil?
excessive gap from worn 3rd main bearing?
how much voltage/current does it put out now, if any?
dead magnets?

a patient writes a note to his Dr: "Doc I have a terrible cough", Dr writes back: "don't worry, everyone has a bad cold this season. Patient dies a year later of Lung Cancer.

Just like you, the Dr. did no diagnosis and leapt to a conclusion. Drs like that get sued...Forum Members, not so much, so it's lots of fun to just throw out suggestions without knowing any background on the vehicle. It costs us nothing but you, maybe plenty! This would be an excellent place to start diagnosis: https://www.mtfca.com/discus/messages/7 ... 760271.pdf

bad magnets could be and often are, the problem. But until you do some research and figure out what you know to be true and either works or doesn't work, you're being led to leap to a conclusion which can rapidly lead to more trouble than you want, if this is the wrong choice.

Until you KNOW the answer to the first 6-7 questions I posed, you won't know for certain which path to take to success

Or, you can just blast away with some chance of success and some chance of failure. The Forum thrives on that stuff.

We've all been where you are right now on not knowing a bunch about the car, so take heart. Do some research on the questions I posed. Sort through the car and eliminate as many potential faults as possible and then and only then do you really want to be blasting the MAG with juice and only if you have to. Right now, neither you nor anyone else can be sure that this would be the appropriate path to take.

Good luck

The replacement contact units are inferior IMHO. I would be lookin for a good original.
Place a wanted post and/or hunt the swap meets.

Good to hear from you Scott C.

I have some originals - drop me a note.

RajoRacer wrote: ↑

Sat Aug 16, 2025 1:09 pm

I have some originals - drop me a note.

There you go.

You could always measure how deep the solder contact is below the top surface of the trans cover mountiing point.
Allan from down under.

Ok, Ok Dr. Scott et al.,

Here is the patient history:

The prior six-month owner, who never ran the vehicle, purchased the patient from an estate sale. Likely, the patient had been in storage for several decades after the death of its long-time owner. Knowing the fuel tank was compromised, several T chapter members and I connected a seperate fuel line to the Kingston L-4 carburetor for a two-mile test run. In which, the patient ran on magneto.

Since then, I have installed:

-new fuel tank
-new sediment bowl and petcock
-new fuel line
-twice dip cleaned carburetor with new gaskets and cork
-all four coils where re-calibrated...with two being replaced
-new spark plugs
-new spark plugs lines
-all wire contacts detached/cleaned/reattached
-New Day timer detached/cleaned/reattached...found to be worn
-new Anderson timer about to replace above
-magneto post cleaned after having found a 1/2 inch size fiber ball
-new 6 volt batteries
-new trickle charger
-changed oil
-new fan belt...which was falling apart and hitting timer wire(s)

Here are the patient symptoms:

I've only had two 1/2 mile test runs where the weak backfiring engine did not like going up hills AND I needed a full tank of gas to overcome the hill slope on my 1/4 "test" track"...a one lane gravel road off my driveway. Hint: always back down to flat area before trying to reclimb a hill.

Patient complaining of four problems...

1) rough engine sound with occasional backfires...tested with a long screw driver and found spark plug #2 made no sound change. Pulled plug to determine it was already blackened and cylinder wet with fuel. (Looked and plugs the my T came with had one blackened/fouled plug.) Cleaned Kingston L-4 carburetor again and found no hole in the float. But, the float was not adjusted to the 7/8th specs per MTFCA Ford carburetor booklet. In same literature, the Kingston fuel valve needles were supposed to be opened to 3/4 turn and not the 1 1/2 turn as I had been advised. Engine sounds better and waiting to replace #2 spark plug to hopefully solve this problem.

2) engine dies when key is turned from ON to MAG. I have tried high and low RPMs and a warm engine with same result.

3) a parasitic electrical leak. The first battery died in one week. The second battery now connected to trickle charger. The ignition switch was pulled out and all wires were attached.

4) first time T owner.

Please advise.

See how easy that was?

your car ran on magneto in the recent past, so I think you can dispel the notion and encouragement to blast the mag ring with batteries - from symptoms listed your car presently runs, al be it poorly, on battery. Get the car running well on battery, and now you know the car RUNS. Then work the magneto issue.

My advice is to work through those listed issues first. You all but certainly still have carburetion issues and ignition issues, and very likely have a faulty ignition switch which at one time would allow the Magneto to provide spark and now only allows the battery to provide spark. If this is the case, it is a very common fault - too common to be summarily ignored in lieu of other more exotic "fixes" in an effort to simply "shotgun" issues. Be methodical, and be sure to identify a specific issue, wheedle it down to a specific cause, and then remedy the cause. So, again, work through all of the "symptoms" and once the car is running GREAT, then you can figure out why it won't work GREAT on the Magneto, too.

If you or one of your helpers is absolutely dying to know what is going on with the Magneto absolutely RIGHT NOW, simply follow the link I previously provided...it will tell you precisely how to check the Magneto directly at the source which will further indicate its condition and potentially hint at any wiring or switch issues.

Search the web for "bringing a "T" out of mothballs" by Milt Webb - excellent series of steps to make the car reliable. Be methodical. Be thorough.

Finally, if possible, resist the urge to "fix what ails it" and then immediately drive it until something else fails and fix it and...so on.

That approach can be devastatingly frustrating, especially on spouses. The wife will be thrilled to go for a ride, but not so thrilled to walk home. She'll tolerate it ONCE. The second time, not so much. I find the hobby to be far more enjoyable to methodically fix every system correctly, once, and simply be done with it, and then enjoy a very reliable car for a long time.

good luck

With possible parasitic electrical leak,... With the size of modern 6 volt batteries, they are not as tall as originals. Part suppliers do sell boards to put under the battery, some need one., some need two to ensure that the battery is higher than the carrier frame so that the positive battery cable bare terminal cannot and will not touch the battery metal frame and induce a short thus killing the charge .

How did you get on checking the timer? Sounds like there may be an issue there if only one cylinder is not firing?

Continue to follow Scott's good advice to check through systematically.

A 'quick and dirty' check on the mag - a headlight bulb attached to leads = one to earth and one to the mag post when the car is running (on Batt). No light = mag not working.

Thank you, for the suggestions. I'll be able to get back to my T tomorrow.

Third Test Run: Did not make it up the hill on my quarter mile "test track'. Tried several times forward. As, the engine ran longer mis-fires were creeping in. By the time I decided to try the hill in reverse, I could not go forward or reverse on a slight slope. Backed down into an open field. Walked home and got on a waiting list to go in for replacement wiring. Then, made a call to a T expert who advised several steps. First, clean the coil box contacts and then switch the coils around to see if it's a bad coil. Drove back and did that. It was a bad coil. The switch gave me enough power to almost get over the hill. Without the top-of-the-hill push by my farmer neighbor, I would have not made it back to my garage. Going to replace bad coil.

Electrical: Since there is already a thick board under the battery that increases its height over the metal battery frame, I'm going to move the nearby metal retaining clip away from the positive terminal to the other end of the battery.

As advised by "Dr. Scott", I will continue to work on getting a properly running engine on battery before advancing on magneto issue.

What happened to Vince ???

Vince hasn't been on this thread here for almost 2 years

his thread was simply resurected out of the ether like so many others recently

the best one being the 6 year old thread with people still trying to tell the poster which timer is best for him

Well, crap Scott - didn't pay attention !

Model Ts have changed a lot in the last couple of years....

Forth Test Run: After replacing the bad coil, my T was firing on all four cylinders for the first time in my brief ownership. Ran the gravel test track and conquered the dreaded hill with no problem and wife cheering in the back seat.

Since that was achieved, I went directly into the...

Fifth Test Run: From my driveway, a 2.2 mile run to the local general store. I live with hills where the roads were designed for horse traffic. Most long hills have a flat built into them to rest the draft horses. So after achieving the first part of the hill, I was able to shift into High gear for the first time EVER. (I took a T driving class in Hershey, Pa where all five models were driven in Low gear only.) WOW, High gear is amazing! The increase in speed and the lower rpms quieted the ride down. And, I was driving on a paved road. Almost no noise! Finally experienced Model T speed. Two hairy moments: 1) driving into the empty general store parking lot, I forgot to level shift out of High gear. So when I wanted to slow down and wrongly took my foot off the Low gear pedal, YIKES! I recovered before driving into a fence. 2) I went over an intersection bump that began a death wobble/shimmy. Stopped the car, pulled on the wheels for any noticeable play...none, had wife view rolling from behind and forward...no noticeable wobble/shimmy, and continued home with no issues. Called knowledgeable T friend who explained the why and recovery from wobble/shimmy.

So...back to the Magneto. I've purchased #1156 bulbs and socket to test output. That will not happen a week. Stay tuned and thanks for the help.

Most driving is done in High.