MTFCA Forum

Since I'm rebuilding the rear, I thought I'd check out the transmission of my 1915 roadster. This is the first T that I've removed the hogs head. It has cotton linings which actually look OK, but one had loose rivets that came right off when I touched them. Anyway, any thoughts on how it looks?


Phil

Drums look ok but those windings are going to give you grief. The winding covering is past the point of no return and as it continues to flake off is going to plug your oil feed tube and put a lot of trash into the oil. It is already missing in places.

I was wondering about the red coating on the coils. What should I do to correct it? Is that a paint like Glyptal?

Phil

To check the trans correctly it needs to be dismantled. Drums crack in the webbing all the bush clearances etc, the magneto field coil needs replacing, the usual way is to use a later set up with a ring gear flywheel so a starter hogs head could be fitted now or later. your head gasket is leaking. I'd say it has been many years ago that the engine has been apart, the hogs was put on with cork gaskets, they haven't been available for years. Could be all sorts of surprises in the engine. The engine mount wood blocks are missing as well.

Whats the clearance between metal tabs holding 2 ‘legs’ of magnets and the field coil ? I like a max of .032 at the top. Drums not scored, lacing wire present, triple gears look good. You asked ‘how it looked’ but, as previously advised, it’d be best to do a total tear down. Especially since the T is new to you…

It "looks" very right for a 1915! Which in itself is quite unusual. It has the correct early style triple gears, which have a wider running surface than the more common later gears. Those early gears were riveted together, and sometimes the rivets weaken and become loose. So if you take it apart for a more thorough inspection, check those gears very carefully.
That style gear was used for quite a few years, and they are not rare. However, a lot of people do not trust the rivets and so replace the gears with the more common later type. Personally, I like the way the early riveted style run better and more quietly than do the later ones.

Your 1915 engine has the double-stacked oval shaped field coil for the magneto. That is the correct one for a 1915, and I believe 1916 and maybe early 1917. They were not used for very long before being replaced by an improved single (no stacking) ovals field coil. The double stack was introduced for the 1915 model year to increase the amount of electricity produced in order to run the magneto powered electric headlamps. It was found to have not really been necessary, and after some time Ford went back the "no stacked" single coils which were considerably cheaper to produce.
Those double stacked field coils are not found often. They were actually used for only a short time. Over the years, most cars that had them from the factory had had them replaced by the much more common and available later style. The double stacked field coils are much more difficult to rebuild than are the later ones. Twice as many coils to rewind, and trickier wiring make them very difficult.
Reworking the whole transmission to engine assembly requires checking and fitting the field coil for best results. Not difficult to do, and changing to the later field coil usually does not complicate it significantly.
Only a truly anal purist would insist on using the "correct" 1915 style field coil. If I had one, and it was a good one, I would have used it. However, I do not have one, so my 1915 runabout has a later field coil inside. If anyone would like to provide me with a proper 1915 field coil? I would only change it IF and WHEN it was convenient to do so (which most likely would be never?).

Glad I posted the photos. No idea what has been done to this car, but it does run and drive pretty well. The rear was worn. I replaced the U-joint, axles, axle gears and drive shaft. The axle and drive shaft tubes were straight, however. Never knew about the wood engine mounts (Lang's #3083?).

Thanks, Wayne, for your comments on the coils. Again, news to me. Would it be worthwhile to get a rebuilt double stack coil assembly rather than trying to redo the old one? I see Snyder's offers them for $345+ core.

Phil

The magneto coil has been painted with DuPont red electrical winding spray paint. I had some with that was the same exact color. When I removed the engine out of my 24 Coupe for the first time many years ago I used some gas to remove the grease from the mag ring since there were a few places that the winding material coming off so I used the winding spray paint the coil. It lasted until I removed the engine again a few years later.

That was before you could get the mag rings rebuilt and that was probably done to your car.
Your car had the engine out and some work was done on it since the mag ring was painted I’ll bet. The drums look good and not grooved so they are probably OK. I would say since the mag ring hasn't been rebuilt it might be a good idea to have it done. I don’t think yours has. If you use the later single stack you may need to use some spacers to get the correct spacers to change it but I’m not familiar with that and others that have done that can tell you how to do it. Wayne S. would know about that.
I bought a dissembled 17 engine and it had a double stacked mag ring that was worth a little more to the rebuilders since they were more harder to come by I guess and later sold it for a few dollars more than a single coil was going for.

I haven't been able to keep up with all the changes in the hobby over the past several years. So, quite frankly. I don't know where we are in relation to many parts and their availability.
I would recommend phoning your preferred model T parts dealer and ask them personally where they are currently in relation to any specific item.

This following area, I will not mention names because I might misremember something and put a right name in a wrong place.
Suffice to say. I and a lot of others that have been crazy enough to play with model Ts most of their lives can remember when the model T's four coils and magneto were a huge mystery. Nobody understood them, or seemed to actually know how to make them work properly. Eventually, a few people determined to right a wrong, and with significant engineering background, set out to learn the truth. What followed was a sort of renaissance with numerous people in the model T hobby seeking to return them back to what was in fact an incredibly effective and reliable system in its day.
Earlier, in the model T hobby, really good field coils could still be found. However, really good ones were disappearing fast. The idea of rebuilding them frightened most people, in spite of the fact that it really did not require major equipment or skills. Several people found sometimes practical shortcut ways to fix them up. Most of these methods involved painting the field coils with something to insulate and stabilize the windings. To work, the wound coils needed to be cleaned somehow. People tried almost anything, gasoline, paint thinner, soap and water, denatured alcohol, I even heard of sandblasting being tried. None of them alone were good enough. A few in combination of a harsh solvent followed by a mild solvent seemed best. Believe it or not, several people advocated putting the whole field coil ring into a fire and burning away all the rotten cotton, dirt and oils. Believe it or not, that actually worked well quite often (I never liked the idea myself).
Once cleaned (by whatever method?), the coils would be painted heavily with Glyptol or some other sort of electrical insulating paint.
Many of those field coils are still working fine now, forty to fifty years later.
Unfortunately, many others are not working so well. Whatever insulating paint was used, tended to dry out, or break down due to heat and oil contamination. And no matter how someone tried to clean them? The wound coils were never clean enough. The paint would shrink or swell depending on chemical reactions, and either way, pieces would begin to break off.
Eventually, a few people found that rebuilding them wasn't all that difficult. Articles published in the club magazines, and other people followed suit, rebuilding field coils for many model t owners. For some time, mostly only the common starter era ones were being rebuilt, however, eventually a few rebuilders set up and rebuilt earlier brass era versions. While not cheap, most model T owners were willing to pay a fair price rather than tackle such a mass of unknowns themselves.
Unfortunately, nothing lasts forever. Some of the rebuilders have had to give up on the work. I don't know if anyone is currently rebuilding the brass era ones or not.
Maybe someone up-to-date on it can let us know? Otherwise, as I said, phone your favorite model T parts supplier.

Like everyone said, the coils need replacing. On a 1915 you can use a single or double stack coils, double stack being what the 15 car was supplied with. The double stack coil plate is slightly smaller in diameter than the single coil plate. Since those coils have to come out, inspect the transmission drums for cracks. Magnaflux or dye penetrate as the drums webs crack. Also inspect the rivets on the drums to make sure none are loose. At the same time, look at the transmission bushings and transmission shaft and consider replacing the shaft and renewing the bushings including the triple gear bushings. Make certain you have the large funnel oil line and clean it out as cotton band material gets into the line and plugs it. Glyptol, red insulating varnish, or Red Coat will add protection to the coils, but not once they are that far gone. With the unit apart, balance the flywheel with magnets attached and triple gears. And recharge the magnets.

If you know the car has been driven alot it would make sense to disassemble and inspect the transmission parts properly.
With the red paint on the mag field , it's been apart before and that needs replacement.
The drums especially reverse and to a lesser extent the low speed does crack . Along with the triple gears and pins and bushings wearing out.
You have it apart it makes sense to go the distance and make it safe for driving the car.

I have enclosed a few examples of where the drums crack as well as the drive plate between rivets.
J and M Machine.

I recommend the single stack magneto coil with the starter notch. Also changed the flywheel to one with a starter ring gear. These recommendations are based on the possibility of added a starter. Both Lang's and Snyder's catalogs show rebuilt mag rings.

The lenght of the 1919 to 1922 coil cores are 25 inches, which match that of the 1915s. The 1922 to 1927 length is 3/8 inch which might require a thicker stack of shims at the four mounting locations.