DU4 BOSCH MAGS

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Model T Ford Forum: Forum 2012: DU4 BOSCH MAGS
Top of pagePrevious messageNext messageBottom of page Link to this message  By John Rogne on Thursday, May 31, 2012 - 06:00 pm:

Found Three mags. Looking for information so I can get smart enough to ask questions.
Model 4 Brass Germany
Model 5 Brass
Model ED18 Pat 10/08 ALUMINUM
Any value They turn, 918-633-4800


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Thursday, May 31, 2012 - 06:39 pm:

Turning doesn't mean much.......the only that matters is spark.
All the Bosch mags have wound armatures with the condenser within.
It costs about $250 to have a new coil and condenser installed.
Of course that's a once in a lifetime expense and when they're hot they're HOT....... :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Thursday, May 31, 2012 - 07:40 pm:

John, weren't you on the Forum maybe a dozen years ago? Your name is familiar.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Thursday, May 31, 2012 - 08:12 pm:

I do high-tension magneto rebuilds on the side, and I've rebuilt DU4s before. When done right, they are awesome mags.

As for price, they can be anywhere over the map. A fully restored DU4 fetches at most $500, and if it's in original condition, it can go for anywhere between $30 to $200, depending on it's condition, of course.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, June 02, 2012 - 01:51 am:

In a previous thread, to another inquirer, I gave about the same price range as Cameron W. I also agree, when they are good, they are great mags.
One other point. The brass ones are earlier and were used on a lot of cars from about 1910 to 1916. They continued to be used on some cars, and lots of trucks clear through the '20s. They were also sold new with magneto mounts for model Ts during that time. Tractors also used them from the early '20s up until at least WWII. Some parts were available through tractor supply stores until recently and may still be.
If you get them, and mount one on a T, without an impulse. The required spark plug gap is less than a standard T. It is given as between .017 and .022 depending upon the source.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Saturday, June 02, 2012 - 02:29 am:

Wayne - Is there such a thing as a list of tractor magnetos that will fit, or, at least are easily adaptable to model "T's? I'll bet some of the speedster guys know,.....harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Saturday, June 02, 2012 - 03:02 am:

The DU4 is a tractor magneto as well.
All the Bosch mags will interchange along with a slew of other base mount magnetos including Dixie, Aero, Edison, Splitdorf and others.
I would NOT mount a magneto without an impulse coupling on anything except a wall or shelf....... ;)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, June 02, 2012 - 04:37 am:

The common size magneto mount has been fairly standard since the '10s. My dad had a Le Roi industrial air compressor that was built in 1959. It used a then modern magneto with an impulse. He had a spare mag without the impulse. It was a direct fit onto the original Bosch mag drive and gear I had on my then speedster. I almost tried it on my car, but we found out about the required spark plug gap. After that, my car ran great on old DU4s. (Most of the time.)
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, June 02, 2012 - 04:40 am:

The common size magneto mount has been fairly standard since the '10s. My dad had a Le Roi industrial air compressor that was built in 1959. It used a then modern magneto with an impulse. He had a spare mag without the impulse. It was a direct fit onto the original Bosch mag drive and gear I had on my then speedster. I almost tried it on my car, but we found out about the required spark plug gap. After that, my car ran great on old DU4s. (Most of the time.)
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By John McGinnis in San Jose area, CA. on Saturday, June 02, 2012 - 09:21 am:

I keep hearing that the DU4 has a feature that allows starting with battery excitation...thus eliminating the need for impulse coupling. Is this so? What are the details on this? All DU4s or a special version?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Saturday, June 02, 2012 - 09:44 am:

John,

To my knowledge, no Bosch magneto ever had such a feature. Of course it may be a special DU4, something that I've never heard of.


Top of pagePrevious messageNext messageBottom of page Link to this message  By bill harris on Saturday, June 02, 2012 - 11:07 am:

Bosch made the DU4 DR4 DA4 and others. There was a provision for a battery with the switch/coil on the dash. Our family's 1911 White uses this system. Start on 6 volt battery & switch over to the DU4 once it fires. No impulse needed.
sw


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ricks - Surf City on Saturday, June 02, 2012 - 11:49 am:

The retrofitted Lycoming O-290C in my instructor's Swift had a "Shower of Sparks" module wired to one mag, and no impulse on either one. He would start on that mag, then switch to BOTH after start. It always worked for him. I bought one of those in later years, but have never played with it. It's akin to a T buzz coil without the secondary. In fact, you might be able to wire a T buzz coil to a non-impulse mag, and get the sparks at TDC and after.

rdr


Top of pagePrevious messageNext messageBottom of page Link to this message  By Layden Butler on Saturday, June 02, 2012 - 10:44 pm:

John and Cameron,
Here is the Bosch Vibrating Duplex system, special switch and coil, it attaches to a standard DU Bosch magneto ( some other models too) and makes the spark plug spark from battery power whether the engine is turning or not. A lot like a stock Model T timer! The switch is pictured in the B position and when switched to M the magneto functions normally as you are used to. O of course kills the magneto to stop the engine.
vd


Top of pagePrevious messageNext messageBottom of page Link to this message  By Layden Butler on Saturday, June 02, 2012 - 10:50 pm:

There was early on a special Bosch version of DU and other models that was called dual, it used a special switch/dash coil combination and the magneto had a second set of points below the first. Starts on battery and runs on magneto. Often seen on brass era cars, that would be "off brands" not Fords!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Sunday, June 03, 2012 - 04:42 pm:

Layden,

I'm curious to see exactly how that system worked. I have no doubt that it did work, but I just can't see how it can use a battery to make a magneto fire, without doing some internal modification to the mag.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker on Sunday, June 03, 2012 - 04:47 pm:

I take that back. If they used a vibrator to send a pulsed voltage into the magneto's ground terminal (the one used to kill it), then that could make that mag's coil behave like a T coil. However, they would have to have a big resistor or something similar in series, since it would be a short if the points are closed in the mag. I suppose it would also cause the mag's magnets to loose their strength over time. But it would work.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Rogne on Sunday, June 03, 2012 - 05:32 pm:

I noticed that the number 5 is marked dual. Also found two Dixie mags 40, 246. If anyone has any intetest in them,I can take to Lincoln. adious@aol.com


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Sunday, June 03, 2012 - 08:52 pm:

At least one, as used on some of the early J. I. Case tractors such as the 12-25 and 20-40, has two sets of points so for battery starting the magneto acts only as a timer. They are non-impulse magnetos.


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