No spark in 1913 Studebaker Model 25 Touring Car

[johnfariss]

I do not seem to be getting a spark from my magneto.  The Splitdorf Mag has been replaced with a Bosch DU-4.  Could the capacitor "condenser" have gone bad?  (I am familiar with caps, as my hobby for years has been restoring vacuum tube radios, including some back as far as the mid-1920s.)  I have a copy of the Bosch manual, and it looks like the capacitor is buried deep within.  If this could be the issue, how do I access the cap?  I see how to remove the points, although I have no done so yet.  Are there any issues I should be aware of going into this?

[Mark Shaw]

 

Note #9 is the condenser in the cut away drawing below:

Edited May 14 by Mark Shaw (see edit history)

[cudaman]

If you haven't already, try disconnecting the magneto end of the wire that goes to the cut-off switch, maybe there is an accidental short to ground in the wiring to the switch.  If the car starts with that wire disconnected, you'll have to reconnect the wire to shut the car off.  Then you can disconnect the wire again and start tracing it to find out where the accidental short is.

 

 

Edited May 14 by cudaman (see edit history)

[johnfariss]

Thanks for the tip, Cudaman.  I tried it and it still did not hit, so that is not the issue.  If it is the capacitor, looks like it is buried deep within, that it would have to be disassembled to get to it.  I noticed however that the magnets (in position) barely attract ferrous metal.  That suggests to me they have been depolarized.  Does that sound right?  If so, I think it would be better to removed the magneto and have it rebuilt.  If anyone has a better idea, please let me know.

[JV Puleo]

The capacitors all eventually fail...

Some time ago David Greenlees did a series on his web site The Old Motor on rebuilding a Bosch mag and replacing the capacitor. I think I remember most of it but don't want to post misleading information so it would be best to take a look at his site.

 

Also, I wonder if you couldn't just attach an external capacitor? Someone with more electrical knowledge may be able to tell.

Edited May 14 by JV Puleo (see edit history)

[johnfariss]

As I said earlier, I am familiar with capacitors from old radios.  One wired across a cap's leads can work, depending on how it failed.  If it failed open, you can do that, assuming you can get to both leads.  However, if one fails by a short, you cannot.  Assuming the old caps in autos were similar to those in radios, especially those from the '20s, they are two sheets of tin foil separated by paper, sometimes buried in wax or tar or in a thin metal rectangular case.  Those used in RCA in the mid and late 20s are very robust, and many (perhaps most) are still functional today.  I have read that they use "fish paper" (whatever that was) in them.  Others--Atwater Kent, Majestic, Philco, Crosley, etc--had a life expectancy of 10-15 years at best.  If the paper rubs through, whether by vibration or acid content in the paper itself--and the two sheet of foil contact, they short out.

[JV Puleo]

Fish Paper is dielectric...it's the stuff "fiber" washers are made of. I believe it's made of rubber. In any case, a few years ago when I was making some special fiber washers I had to find some...before I'd ever heard the term. It was a challenge. After all, who would think of "fish paper" as the proper term.

[DFeeney]

I am looking forward to the solution to your spark problem.  Keep us posted. 

[HarryLime]

https://www.magneto-repair.com/

     I have no experience with this company. Looks thorough. Good Luck. 

[TerryB]

Here’s a link to a YouTube video on re-magnetizing a magnet magnet.  The guy first builds his magnetizer and then shows how to use it.  Very interesting!

 

 

[johnfariss]

OK, my magneto is working.  I seem to have a problem at the switch however.  There are two settings, "M" and "B" which I assumed mean "Magneto" and "Battery," with an unmarked center between the two.  I would have thought that was the off position, where the magneto was grounded.  It turns out however that when the switch is thrown toward "M" that grounds the magneto.  Is this correct, or has someone messed with the switch?

[JV Puleo]

It is not correct. It sounds like someone has fiddled the wiring. In the "M" position the mag should not be grounded.

[Bloo]

The "switch" is a coil and condenser and is part of the low tension magneto that is no longer on the car. On a stock model 25, B is battery, M is magneto, and center is off, just as you suspected. I have no idea how it might be have been rewired.

 

All the Bosch magneto wants is to be grounded to shut the engine down.

 

Edited May 24 by Bloo (see edit history)

[Bloo]

On further thought, it is probably normal under the circumstances. The Bosch magneto is high tension, and is self contained. It only needs to be grounded to be shut down.

 

The Splitdorf is a low tension magneto, and it is using the firewall mounted coil even when running on magneto. To shut this down, Splitdorf may(?) have just disconnected the coil. There would have probably(?) been no reason for a grounding contact at the center position of the switch to exist. I imagine when adding the Bosch magneto someone just had to find a contact in the Splitdorf switch/coil/condenser that would be accessible from the outside and use it. It probably wouldn't be in the center position.

 

In some thread about this car (there seem to be several) I think there was a link to the internal wiring of the Splitdorf switch/coil/condenser assembly as used on the Model 25. That could probably solve the mystery, but I could not find my way back there.

[37_Roadmaster_C]

I have helped @Bloo with his SA-25, but I do not remember anything about the internal wiring of the switch or Splitdorf magneto. My part was mostly to help with a modern battery pack. In any case, Bloo hit the main point, the Splitdorf requires "external" power to provide spark. This power comes from the internal low tension magneto coils and magnets in conjunction with the external coil and condenser in the switch OR an external battery. In 1912 the battery was a disposable alkaline battery which was used for starting as the low tension magneto was very poor at hand cranking speed while the battery allowed a full hot spark while cranking. Once started the switch was turned to Mag and all was good. To stop the engine you disconected the battery or coil/condenser by placing the switch in the middle position.

Another thing about this car was the Acetylene hot shot starter (my name for it).  Bloo can tell you more as the car has not had this since I helped him get it going again 15+ years ago.