Wanted: Bosch DU4 Twin Spark Magneto.

[edinmass]

Looking for a Bosch dual spark, twin plug DU4 magneto. Photos of needed unit below. This is not for a spare on the shelf, my car is missing the correct unit and I can't run the second set of plugs. Any help appreciated. Ed

 

DR-4 Dual is a possible correct model ID.

 

Please contact me through the AACA personal message system.

Edited July 12, 2021 by edinmass (see edit history)

[PFindlay]

I believe the mag shown is a DR-4 dual, not a DU-4 dual.

[edinmass]

13 minutes ago, PFindlay said:

I believe the mag shown is a DR-4 dual, not a DU-4 dual.

 

 

Thanks, is there any "go to" guys on these units? Doesn't seem there is much scolarship on any early magnetos.

[PFindlay]

2 hours ago, edinmass said:

 

 

Thanks, is there any "go to" guys on these units? Doesn't seem there is much scolarship on any early magnetos.

In 2019 I bought a rebuilt DR-4 from Mark Maikshilo at Mark's Magnetos in Connecticut.  860-537-0376.

 

I've dealt with him a few times and find him very knowledgeable and reliable.

 

 

[edinmass]

More photos, and a better look at exactly what I need............

[1912Staver]

You can look up the serial number and get a date. There was a very good Bosch mag article published in the HCCA Gazette several years ago that included dating information.  But I have been under the belief that these " D4 " units { the ones with the big brass " spider " to retain the rotor cap } are quite early, perhaps 1914 - 15 at the newest. Anything newer than late Brass Era probably used a DR 4 dual. Not 100 % sure when the DU / DR series came out but I have in my mind it was around 1914, so the earlier D series units would have been just using up on hand units from the time of DU / DR introduction onward. 

The new White ? It is a later teens car isn't it ? Unless the factory lists a D series mag , I would expect a DR.

Any of the Dual 2 Spark mags are pretty rare , but if a person is willing to pay the going rate I expect they can be found.. Probably more 2 spark mags sitting on shelves than cars that can use them. Just a matter of convincing someone to turn one loose.

 

Edited July 15, 2021 by 1912Staver (see edit history)

[edinmass]

The engine with the dual plug was NOT production. It was developed in September of 1914, and first ran in  1915. Thus a D4 Dual - twin spark would be correct. I'm familiar with hard to find items, but as you say.....there are more on the shelf's as spares than there are cars. Fortunatly the car is running fine as is, so it's just about having the right parts on the car.....my back isn't up against the wall. I'm certain I can find one, it's just the number that I have to give. The only two White's in the world that have this application don't have correct units on the car. I expect I'm the only one stupid enough to want his car 100 percent correct. 

Edited October 8, 2021 by edinmass (see edit history)

[gossp]

You have the contacts to find them… every early fire truck collector seems to have several on a shelf. I know my pockets have failed to be deep enough to ever get one. If work keeps me away from the Gilmore this weekend I will check on the stash nearby that used to have a few. 

[edinmass]

Happy to pay a finders fee on a good core or working unit.............that said, I don't expect to buy one for three hundred dollars.........I can hope, but don't expect it. We shall see what turns up.

[ak]

A D4 will not mount where a DU 4 or DR 4 is spec'd.  They are entirely different magnetos with different mounting plates.  The D4 has three horseshoe magnets where the DU and DR and ZR mags have but two. 

In any event, a 2-spark (not twin spark) magneto will provide an advantage over a standard magneto only if placed on a T-head engine.  It will do nothing more than what any run of the mill DU or DR single spark would do if placed on anything other than a T head engine. 

John

[edinmass]

John, my car is a T Head.........it’s a mono block with four valves per cylinder. Photo below is the engine I have. This photo is the single plug version, mine is the dual. Magneto’s are new to me from this era. Thanks for the heads up. I know it’s a 45mm application.
 

 

 

Edited August 2, 2021 by edinmass (see edit history)

[Terry Harper]

Ed,

 

Check with the magneto folks over on the Smokestak Forum. When I needed an American-Bosch AT6 (a rather hard to find item)  it was one of those fine folks that came to my rescue.

 

Smokestak Forum - Magnetos, Ignition, Coils & Spark plug Section

 

 

[edinmass]

I was there a few weeks ago.....nothing. Thanks for the tip.