Is anyone familiar with the room necessary for an impulse mag to be added? This Speedster project has a dual ignition mag. If someone is aware of the space needed, does it look like there is room on this mag? I'm unsure an impulse mag may be added to a dual ignition mag, but don't think that should be a problem.
Having only repaired one impulse coupling before... my experience is quite limited. But the one I worked on was simply a stand alone coupling that replaced the typical rag or hose clamp type coupling as shown in your picture.
When the impulse coupling was installed on the tapered shaft it fit close to the housing and was about 3" in diameter, the end of the shaft was about flush with the end of the coupling.
The impulse coupling was a really simple device. Basically just a spring loaded coupling that is held off by a centrifugal ratchet. So that at low RPM the coupling would wind up and release to snap the mag to achieve a hotter spark. And at higher RPM it simply locks up solid. I could see the advantage while hand crank starting.
I ran a Matco cross drive on my 27 roadster for a few years before I sold the car. Never had a impulse on it, and could still hand crank the car just fine. The Matco had a casting rib that wouldn't allow the impulse to fit anyway. The pic you posted looks like there is plenty of room to mount the impulse coupling to me.
However... I think all the mags have the same basic tapered shaft configuration despite brand or series. But the drive end isn't always so standard. You may have to make the drive hub to fit your specific application...
Thanks for the information. I had an impulse added to a Bosch on a Buick years ago. Later, I wished to add one to our Model K, however was told there wasn't room. I wondered about this Speedster project. There isn't a way to add/use coins or another ignition source, so an impulse may be the way to go if there is room.
Nice mag, looks very similar to mine only the dual spark model. I have the impulse coupling on mine as well as the plug wire ends (I hear they are hard to find) you appear to be missing. Looking at them they may not be too difficult to reproduce. I'll try to get a picture of them for you later.
Mine is a DR-4, I need to find the pieces to allow it to be run as a distributor still.
Thank you for the information. I'm not sure the regular plug wire ends would work, particularly on the back row unless them made a stepped version so the back row doesn't short with the front row?
I hope an impulse can be added, as the mag is the only method of ignition (albeit it dual). Can these mags be used as a distributor too? If so, maybe adding a coil and condenser could allow me to crank start on distributor then switch to mag? The Ford Model K magneto works that way, however it's an altogether different type of magneto, actually the first Capacitive Discharge Ignition (CDI).
There are other lesser known Bosch options too...
I would need to see the back of the mag or apart to tell if it can be run with a coil. You can see where the second set of points should be with the covers off.
Rob I had to move the bosch du4 mag back 5/8 inch when I put an impulse coupling on my wifes 14 touring. Much easier to start with the hand crank.
Rob, this may not help at all but I like the ideas!
An IH F6 mag that's converted to 12 volt. The coils I had were all bad... Not a crankable engine tho. It's on a UD-16 engine from the 50's.
Works good! Yes, the nasty, super-recharged magnets are sitting with keepers, someplace in the shop.
Switching back and forth? Cool notions! Do it!
The Bosch ZR4's impulse uses 1-7/16" from the case to the end of its coupler.
Keep us posted if you would.