Author Topic: Advice about MD2P4 Magneto  (Read 4725 times)

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Offline Robert_Lee

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Advice about MD2P4 Magneto
« on: 06 Jan 2005 at 13:09 »
Dear All,

I am helping my aging father clear out many old automotive components from his sheds.

One of the items is a magneto type MD2P4.

I put the item on Ebay and sold it recently, but there remains doubt about how complete the unit is.

Alas, I am not sufficiently technically competent to clarify the queries raised and was hoping to garner a more informed opinion or expert from someone who could help. I made a connection between the HT output, my fingers and the body and span it up by hand and got a shock from it, hence thinking that all was OK and functional.

I have been advised that the points, points carrier and cap are missing. Could someone please comment on accuracy of this, since I am unable to know one way or another.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=7941491469&ssPageName=STRK:MESO:IT


Many thanks for your help, Robert Lee

Offline Doug

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Advice about MD2P4 Magneto
« Reply #1 on: 07 Jan 2005 at 01:34 »
Robert,

Yes the magneto is missing the contact breaker assembly, and the protective cap that covers it.  The contact breaker assembly plugs into the female taper dead center of image ef_1_b.jpg (note how un-weathered that area is.)  The breaker is operated by the internal cam ring, still in situ.  For the magneto to work the electro magnetic field needs to  reverse and collapse.  Normally this is done by the contact breaker separating abruptly and at the optimum time to maximize the spark intensity.  But the same thing will eventually happen on its own by rotating the armature.  Were the contact breaker fitted and functioning you would have got a much stronger shock.  

The magneto has shielded outputs to prevent radio interference, so without looking up that model number I am thinking military.  Perhaps fitted to a Douglas generator set, ex- war department.  The motorcycles from 1946-1955 used a Lucas MagDyno to provide lighting current in addition to sparks.  Not sure if the commercial engines after the war use shielded ignition, but doubt it as it added to the cost.  

-Doug

Offline Dave

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Advice about MD2P4 Magneto
« Reply #2 on: 07 Jan 2005 at 09:21 »
Doug, couldn't find ef_1_b.jpg... is this it?


Offline Doug

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Advice about MD2P4 Magneto
« Reply #3 on: 07 Jan 2005 at 13:19 »
That is the right one.  

Must have copied the wrong name from the pictures properties.

-Doug