car will not run on magneto

[Mike]

Hi to all,
I am working on a 1919 Model T and my question is when the car is running on battery the car runs well, when I switch it from batt to mag the car shuts off, The wiring is correct and is new 2 years old, I cleaned the mag pick up, and replaced the ignition switch.

Any suggustions would be helpful

Mike

[Doug Money]

Have you measured the mag output with a 1156 bulb and analog meter?

[Mike]

No I will do that now! and I will get back to you tonight

mike

[Mike]

Ok I am new to Model T ! Can you tell me how to test the mag with a 1156 bulb and a anolog meter

Mike

[Greg Jones]

Did it previously run on magneto and this is now a new condition, or has it been this way since you got the car?

[jkeesey]

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Come on Mike its just a ford! All kidding aside the ideal T mag puts out near 24 volts. Just hook your voltmeter to the mag output when running and see what shes got. If your running well on batt your coilpacks must be balanced fairly well.

[Doug Money]

Run car on battery and hook a 1156 bulb in line with an analog voltmeter to the mag post. Post your readings at idle and fast idle.

[Mike]

Greg,
Yes it ran very well on mag, I changed the rear and now i have the mag problem

Mike

[FRANK PKNY]

Need to check the voltage with a analog meter at the mag post. Hi idele about 24v AC . A digital meter will not give you a good reading. Then follow the circite from the mag post to the post that goes to the coils. A real good rebuilt mag will put out 30+ volts AC the coils like the ac voltage better than the DC from a battery. I don't know why but that is the way it is.

[Doug Money]

Frank, the higher voltage increases the ramp up time of the coils so they fire faster increasing timing. This makes the engine run a bit faster. The AC voltage helps keep the points from burning since the charge reverses from time to time through the points when the coil is charging.

[Greg Jones]

Yes you should test the mag output as recommended, but I am intrigued by the sudden change. When you say you changed the "rear" I assume you mean rear axle? Did you disconnect any wires, or that sort of thing? I can't imagine changing a rear end would cause this. Do you have any idea of the condition of crank endplay?

[Greg Jones]

Also, make SURE you really cleaned the magneto post, including down inside the hogshead under where the post screws in. I had a problem once with the car missing and finally dying while on magneto. I pulled the mag post and thought, aha!, here is some band lint causing the problem. Well that was only part of the problem, there was still a hunk of lint inside on the coil ring post. Only spotted that by looking in there with a flashlight and yanked it out with thin needle nose pliers. Worth a look, anyway....

[Mike]

Greg,
Yes I changed the rear end assembly, I did not check the end play of the crankshaft.
I did pull the mag out of the hogs head and really cleaned it up

[ljbohlen]

Do you have an outside Mag fed oil line?
Sometimes these can short the Mag.
Make sure the fitting for the line is not screwed in to tight as it will contact the mag post and kill the Mag.

Also check your switch. Some times weird things happen, you change out the rear end and for some unknown reason the switch decides to crap out the next time you start the car. Totally unrelated but it will have you chasing your tail for weeks or more....

T's are the most ornery machinery ever built.

Good Luck.
Larry

[Greg Jones]

Aha! So the magneto was out. I assume you mean the whole transmission with the magnets on the flywheel. Did you also remove the coil ring that bolts on the back of the block? If so did you notice any shims behind it? The gap between that coil ring and the magnet contacts on the flywheel needs to be 0.025 to 0.040" if I remember correctly. That is actually a pretty narrow range when you think about it. So my question: Were there any shims and did you replace them as you found them? Dont feel bad if you say you didnt put them back in-lots of people have done this. Not looking to make you foolish, just asking the questions to help you get to the bottom of your problem. Something changed physically since it was last running on mag, obviously. Now to figure out what....

[jkeesey]

I think he meant the mag pickup not the entire magnetto.

[Doug Money]

First step in trouble shooting is to see if there is in fact any voltage coming from mag as described above. Otherwise you are just grasping at straws on the fix.

[Greg Jones]

Of course, do the test. Was trying to slueth back to what has been changed since it was working. But do the test.

[Mike]

I did some tests this weekend, I am getting 3 volts at the mag pickup. I recharged the magnets and I still get only 3 volts.

Mike

[yachtsmanbill]

Three volts at what engine speed? ws

[Mike]

Engine speed idle , fast idle and high rpm 3 volts
Mike

[Doug Money]

This was an analog meter? Not a digital meter?

[yachtsmanbill]

Get that 9/16 & 5/8 wrench handy! Check for grounding in the MAG plug first. The can short as well! ws

[Mike]

Good morning, yes it was a analog meter. I am looking into using a coil and distributor.

Mike

[FRANK PKNY]

Originally Posted by Doug Money

Frank, the higher voltage increases the ramp up time of the coils so they fire faster increasing timing. This makes the engine run a bit faster. The AC voltage helps keep the points from burning since the charge reverses from time to time through the points when the coil is charging.

Thanks Doug, I understand why after reading your post. AC alternating current keeps the points from pitting in one direction therefor the points last longer. DC you can see the metal deposits going in the direction of the current. The higher voltage and ramp up time makes a lot of sence.
Great I am always learning something new even at my age. Thanks Frank

[Doug Money]

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Glad to be able to help Frank.

[Mike]

Anyone covert to coil and distributor setup

Mike

[FRANK PKNY]

Let me go back one more time. Dissconnect the wire coming off the mag pick up. Use an analog meter , set for ac voltage range 0 to 50 vac . What is the reading at high idol? ( the rpm at driving in high gear about 25mph). You may not have recharged the mag properly or you need to pull the engine and examine the coils and magnets then reset to gap as stated prior. On original coils the old cotton insulation and laqure breaks down and could short out also the magnets loose their charge over many years of use. A new rebuilt mag will put out 30+ volts ac if set up correctly.

[Doug Money]

Dont forget the 1156 bulb between the mag pickup and meter terminal. That loads the mag the correct amount to simulate the coils.

[yachtsmanbill]

My original magnets, and new Wally coil ring gives me 5-6 volts at hand cranking speed. Havent checked it running yet, but its STRONG!... ws

[columbiA]

Ive recharged the mag by using the instructions in an old Dykes manual.Ive used two 12V batteries in series.Follow the directions carefully and if the coil ring is good,it should put out over 30 Volts AC. T,s run best on mag.If you change over to a dist system,then you are losing a lot of what makes a "T" a "T".With a good mag,you can quite often get free starts with a warm engine simply by turning on the switch.

[columbiA]

In my previous post,I should have said that you will get free starts if you switch to BAT to start.I used a 6V rectangular lantern battery for starting.

[Mike]

Good morning,
Thank you all for your help!! I did all the tests with a analog meter and a 1156 bulb.
At idle 1156 bulb dim 5 vac. At mid throttle 1156 bulb dim 5 vac. At high throttle 1156 bulb dim 5 vac. I was asked by the owner to look into a coil and distributor set up, any thoughts on those units ????

Mike

[Doug Money]

You could always throw a 12 volt battery in until the mag gets repaired down the road.

[Mike]

Can I install a 12 volt battery in the car without damaging anything????

[Doug Money]

Some say it's hard on starter. Many have been using 12 volt just fine. Change the bulbs. Do you use a voltage regulator on the generator?

[FRANK PKNY]

Mike, if your ring gear is in good shape 12volts will work. The six volt starter slams kinda hard to the ring gear, I used a new replacement starter that is 12v and have not had any problems in about 5000 miles. (The starter is advertized in the model T mag. ) Sounds to me like you may have a need to pull the engine at some point. T's are fun to work on. If you follow the service manuals and ask advise when your not sure , you will not go wrong. I converted my present 1915 T to a starter engine. Bad back and torn sholders from a horse related accident did not let me crank any longer. I enjoy driving a T I have four antique cars but the T is my favorite to drive. An easy fix right now is going to a battery 12v. It takes a long time for the points to go bad on battery , as stated by Doug the Dc is not quite as good as the AC power. I think 10,000 miles you would need to tend to the coils. Of course I am assuming that they are in good shape to start with. Most people that change to a distributer do so because they don't understand the modet T ignition system. ( open a can of worms here). Frank

[yachtsmanbill]

Over the last winter I rebuilt the POLLINATOR from a pile of parts. I installed a NEW 12 volt DELCO starter from LD BECKER & Co and am now waiting for the gear driven 12V alternator due here this week. There is NO substitute! The starter uses a button and a standard Ford fender mount solenoid. The original beat up ring gear seams to tolerate the Delco starter just fine.
The car runs fine on 12V with the coils, but switch over to MAG and its a big improvement. One of the surprises of the MAG besides being about 32 volts AC is the long dwell angle that produces a longer lasting spark impulse at the plugs. Wally Zumansky in Chicago built the coil ring, and the ORIGINAL uncharged magnets do the trick.
Even a cold start is a bump on the starter with ZERO choke and she takes off. All the yahooze at the mtfca boo-hoo 12 volt stuff, but theyre a bunch of weanies anyway. Real sealed beam headlites with GOOD tailights are todays necessities. PERIOD.
Even when I was running some bum coils, the POLLINATOR strolled along effortlessly at 38 mph (GPS), with a lot of throttle left. Its only gonna get better next week with 4 new coils coming from Kintukky! ws

[Mike]

Doug,

The car is all original, it has a good generator and original cut out on the unit .

Mike

[Doug Money]

Then all you have to do is change the bulbs and fire it up.

[Mike]

Good afternoon,
Last night I installed a coil & distributor set up in a 1919 Model "T" Touring car. What a great improvement in my opinion, the car runs great sounds the same and was easy to install.

mike