Is there a way I can test the mag coil ring? It is on the bench.
Yes. First visually inspect for any bad insulation on the coils. Using a 2A battery charger, place one contact on the solder button at the top of the ring and the other to the metal ring. Next, take a thin flat piece of metal and run it over each post of the coils. You should have magnetism at each post. If not, where it stops you will have a break or a short to the ring.
Here is one thread where Colin Bowen from Australia describes the procedure: http://www.mtfca.com/discus/messages/179374/245394.html?1320564797
"Both magneto rings were rewound and checked by applying 12 volts and using a hacksaw blade on each pole. I also checked each pole with a compass and noted that it changed between north and south as I went around the ring."
Note Colin's rings were rewound. Putting an old original mag coil ring back when you have the engine apart is taking a risk, the old insulating material is mostly rotten by now and when it eventually develops a short it's just about the most inaccessible part of the whole car.
The electrical system manual from MTFCA describes how to rewind the coils yourself: http://modeltstore.myshopify.com/products/service-manuals
If you don't have the time to do it yourself you can get rewound coils from Wally Szumowski or RV Anderson: http://www.mtfca.com/discus/messages/118802/131292.html?1276224076
Is it an original ring that hasn't been redone or is it one that recently was restored?
I have 2 original rings that were still working but when I was rebuilding the the engines in my 2 T's I went ahead and replaced them with rebuilt one's from Wally S. (I cant remember his last name).
Mags rings, a good radiator and good tires are a MUST if you want to enjoy your T.
It would not be good to get your engine together and find out a while later after you were running it that the mag shorted out as the old insulation was coming off.
If it needs fixing and you're inclined to do it yourself, the MTFCA Electrical System book tells you how.
This is an old ring, has not been. Re- done
This is how I rebuild it here in Belgium.
In my view reusing an old magneto field ring is fraught with risk. There is nothing you can do to patch it up like new. If it fails, which they are prone to do, it is not like a spark plug to replace.
I suggest you get a quality rebuilt magneto field ring from Wally Szumowski or Randall Anderson and put your mind at ease. Both do a great job and the price is not excessive.
You can rebuild it your self as suggested, but in my view the learning curve is steep for a one time project.
Ron the Coilman
Than all of you. Guess I will order a rebuilt unit.
When I first purchased my '26 Model T in 1970 at the age of 16 and began to restore it, I had very little money and there was no internet or MTFCA to consult so I had to make due with what I had and what I read in the Ford Service Manual and Ford Essential Bulletins, which were the only sources of information I had, so needless to say, I was not aware that an old magneto should not be used, even though I had no idea how to rebuild one or knew of no one who could rebuild one.
I guess I was lucky in my ignorance, because I used my common sense to salvage, as best I could, the old magneto with its' frayed insulation and it lasted for 40 years until 2010 when I re-built my engine again.
In 1970, in order to salvage my magneto coil, I soaked the magneto in mineral spirits to remove all of the oil out of the insulation, changing the black mineral spirits numerous times until the mineral spirits was clear and all of the oil was soaked out of the magneto coil. This took over a week of constant soaking. I then let it dry for a couple of weeks until I was sure it was totally dry of mineral spirits. I then painted on many layers of GE Glyptal until a thick hard layer covered all of the coils and let it dry for another week. Luckily, the coil was good, for I do not recall testing it to see if it was good, because after I got the engine reassembled and started it, it cranked right up and ran on mag and continued to run on mag for 40 years.
All I'm saying is, that it is possible to salvage a original magneto if you:
1. Start off with a functional original magneto coil to begin with.
2. Are young and know no better.
3. Lack the skill, time, knowledge, materials and wherewithall to wrap the coils yourself.
4. Are too poor to afford a rebuilt magneto and must make due with what you have.
5. Take the time to do it right, using common sense as your guide.
6. Are lucky like I was that the magneto was good and the Glyptal held for 40 years.
What Ron said,and those are a bear to clean!! Bud.
I like your story on being lucky that your coil ring worked after your 'restoration'
Did the same in the early 80's but, to speed the drying of the gyptal, put that ring in the wifes' oven for a bit of a bake. Oh My....did the smell waft of burned old oil and red enamel, learned a valuable lesson.
Get a restored one from the experts, and never use the wife's stove for T parts