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MG MGB Technical - Electronic Ignition - Just Wondering

There seem to be a LOT of opinions pro and con on this board regarding electronic ignition vs. points. I kinda like old-fashioned points myself, but these discussions actually raise some interesting technical questions. The first of these regards vacuum advance.

On cars like my chrome bumper '73 B, the vacuum advance is driven from the manifold. If I'm not mistaken, however, some if not all of the newer electronic systems - particularly those packaged with new/rebuilt disty's - require "ported" vacuum (presumably from the carbs). How is this conversion accomplished for the earlier cars, where the vacuum was engineered to come from the manifold?

Rick
R. Stevens

Rick
If you look on the web there are computerized ignition systems for the MG, put together with parts from modern automotive computer systems. These can handle everything - not the least of which is timing and vaccum advance.

In contrast the simple add on Crane 700 or pertronix ignition does little more than replace the points and condenser in your stock ignition. All the timing, vacuum advance settings, etc. continue unchanged. You just get rid of the darn points and should not have to look inside the distributor cap for a long long time
Barry
Barry Parkinson

Rick, I have used a Crane 700 system on my 74 for over 7 years and I still have the vacuum advance hooked to the manifold. Everything operates the same as a points system as Barry p[ointed out.

Clifton
Clifton Gordon

This thread was discussed between 20/08/2006 and 21/08/2006

MG MGB Technical index

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