So I am starting to decode DaVinci's speedster. Originally, about 1970 give or take, somebody built this unit from a piile of parts... OK. The 1926 engine is a battery,starter and generator delete power plant. Blocked off, and there for a MAG only system.
I pulled the hogs head off today to verify the missing reverse band nut, spring and washer wasnt in the sump. Sure enough, somebody pulled the starter and dinged the mag coils. And now the question...
I take the trusty OHM meter and check the coils. Touch the two stabs together and zero the meter. Stab the mag plug contact and the block and it shows continuity. Should this be infinity (open) or closed. Is the coil ring grounded? willy




We wont even get into the rivet burns on the drum for now

It is normal for the magneto ring to measure nearly a dead short from the solder pile on top to ground on the engine. The total resistance is only about 1/4 ohm which is just about the same as a dead short depending on where you have your test probes. Unfortunately if in fact the "nick" of the mag ring at the starter location has caused a short to ground there - it probably would be near impossible to prove or disprove it with an ohmmeter.

Willy,

The coil winding is effectively one continuous piece of copper from the Magneto post to ground. An earlier post (2008?) indicated a good magneto coil reading is less than 1 Ohm, closer to 1/2 Ohm.

So in other words, I should spin it with a volt meter attached? What should I get at hand crank speed? Also, if I remember, thats alternating current?? willy

Bill
I would'nt agonize over the damaged field ring winding insulation and magneto output now.
The transmission is in serious need of repair.
When you repair the transmission, rebuilding the flywheel and installing a new field ring will be mandatory.
When you get to that point I can provide guidance and help.
Ron the Coilman

Thanks Ron! I knew that was inevitable! All the T-ing Ive done, Ive never had a trans apart. At that point, the flywheel needs a ring gear, and the magnets need a charge... kinda screwdriver weak.
Ive seen several rebuilt coil rings for sale lately and $160 seems steep since the last one in 1970 was free LOL!
Right now, I am trying to piece together whats missing and put it back together minus the bands and try to fire it. No doubt she needs some internal attention. Maybe I should just go ahead now and save the extra work. I just have a "Jones" to go for a spin!
Do you rewind mag coils? If so we will do business again! I bought 4 coils from you about 8 years ago and they are still hotter than a pistol! They reside in a 26 coupe that I sold to a pal. willy

Wally Suzmowski's rebuilt field coils are definitely worth the bucks- properly installed, it's like turbo for your T when you switch to mag

At $160, that's $10 per coil, (16 coils on a coil ring). Given what's involved to rebuild each coil, that's a huge bargain!