Hi Ray:
With respect to your erratic voltage readings, you may want to consider
using a moving-coil voltmeter. That is, an "old fashioned" meter that uses a
moving pointer on a scale, rather than a digital multimeter.
A DMM, depending on its design, can be susceptible to errors and erratic
readings in the presence of electrical noise (unwanted pulses).
In your case, it may be that the ignition system is farkling the DMM's input
circuit with noise pulses. These noise pulses may be screwing up the DMM's
internal analog-to-digital converter, making the displayed digits do a
dance. Noise can "ride" the alternator or generator circuits and not affect
the Healey's regulator or battery, but the noise can affect the sensitive
circuits in your electronic meter.
Such noise is typically radiated from the spark plug wires. It's the same
noise that sometimes affects AM radio reception in a car.
Try another DMM, or use a VOM (volt-ohmmeter) or just a standalone
panel-type voltmeter, to make your tests.
I'd be interested to hear if the eratic readings go away if you try a
regular voltmeter, not a digital multimeter..
== Alex in Maine
1960 BT7 3000 Mark 1 - "The Blue Mainie"
Former owner of 1957 100-6, and 1967 3000 Mark III BJ8
http://users.adelphia.net/~alexmm/ai2q.htm
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