To finalize this thread, I replaced the entire distributor assembly with one with the electronic ignition built in.  It was cheaper to do it that way than to buy a new Pertronics Ignitor and I got a new cap and rotor as well.  Car has been running fine for the last two days.  In short, I have no clue what precisely was wrong but now I have new fuel line hoses, 47 years worth of silt removed fom the float chamber, new manifold gasket, new exhaust system (which I found rusted out and broke while replacing the exhaust gasket), new plug wires, found a missing bolt and broken (and improperly mounted) exhaust down pipe mounting bracket, and a new distributor.

So the moral of the story is:  If you can't figure out what exactly is the problem, throw money at it and maybe it will fix itself.

Thanks for all the useful advice.  It is always appreciated.

Garry 

I agree, 9V is pretty low.

Check all connections from battery to ground, solenoid, ign switch, etc.
I fitted an Accuspark stealth (progammable advance) module to mine recently, and found the same problem. It would not fire below 11V!
So I sold the BIG Bosch starter I was running, and fitted the old Lucas again. Battery is the same 640CCA, near new. Works fine now.

As Larry said, 9V may be a bit low to power the Ignitor module.  

Were I in your position I would temporarily re-fit points and a condenser.  If the car starts and runs on those, start working your way through the system to see what you can do to get the cranking volts on the coil a bit higher (clean connections, try running a white wire from the fuse box's white wire to coil (+), etc.)

9 volts on cranking might not be enough for the Ignitor. I don't know sepcifically about Ignitor but other electronic systems I am familiar with require a minimun voltage.

Black text is Doug's, red mine:

So, full voltage on coil (+) with the key in the run position?  Have you tried what Kevin suggested (connect a volt meter between coil (+) and ground and watch the meter while you crank the engine on the starter)?  Voltage drops from 12.7 to 9vdc roughly when cranking.

Where are you seeing the spark when you say you get a spark on releasing the key  (Main coil terminal with a spark plug in it, all the plugs out and resting on the cylinder head, other) ?  Describe where you are seeing the spark.  Main coil terminal with spark plug and its wire attached.  Jumper wire to ground at plug.  See spark once in awhile and almost always when releasing the key

What did you do to test the coil?  The coil only makes high-voltage for sparks when it 1) charges up via a connection from coil (-) to ground and then 2) that connection to ground is broken.  With the Igniotor module disconnected there is no path to ground so the coil will not spark.   Please explain what you did in your test. Checked resistance between center pole of coil to + and then from _ to +.  Seem to have correct resistances, one high and one low.  Don't remember the readings.  For what it is worth, the coil is brand new.

What wires do you presently have connected to the coil?  (Please list them all by color and terminal connection). 

+ Red from ignitor, White to battery somewhere

- Black from ignitor, White with black tracer to ground somewhere

Lastly, did you reset the static timing once you installed the Ignitor?  Really have not mucked with the ignitor since installing it 12 years ago.

You all think the ignition switch is ok?  Any other idea of things to check would be appreciated.  If you were tired of being stuck at home and were going to throw money at this, what would you replace?  (I suggested to the wife that I buy another car and replace everything part by part but she was not receptive to that idea!)

Garry

So, full voltage on coil (+) with the key in the run position?  Have you tried what Kevin suggested (connect a volt meter between coil (+) and ground and watch the meter while you crank the engine on the starter)?

Where are you seeing the spark when you say you get a spark on releasing the key  (Main coil terminal with a spark plug in it, all the plugs out and resting on the cylinder head, other) ?  Describe where you are seeing the spark.

What did you do to test the coil?  The coil only makes high-voltage for sparks when it 1) charges up via a connection from coil (-) to ground and then 2) that connection to ground is broken.  With the Igniotor module disconnected there is no path to ground so the coil will not spark.   Please explain what you did in your test.

What wires do you presently have connected to the coil?  (Please list them all by color and terminal connection).

Lastly, did you reset the static timing once you installed the Ignitor?

Check the ignition terminal (white wire?) on ignition switch whilst cranking.
I had this problem on mine 5 years ago, it needed a new switch to fix it.

I recently bought a new (made in China, white box) switch for another Mini, it had this same problem out of the box. I sent it back. Does nobody have Quality Control these days??

Not helpful but amusing nonetheless/

Thought I had this under control, but don't.  Here's the deal:  77 Clubman blue, 1098, single carb, Pertronix Ignitor in dizzy, new dist cap, wires, coil.  Symptom:  No spark at coil until ignition switch released.  Checked/cleaned grounds, low resistance from coil to engine and body from negative post of coil.  12.7vdc at positive post on coil. No spark from coil until key released.  Checked coil statically per procedures elsewhere on net.  Tests ok. No spark even with Ignitor wires pulled from coil. 

Possible irrelevant fact:  Found strap between ignitor base plate and dizzy had been severed by rubbing against post in dizzy.  Replaced.

What else can I do, test, buy, or other wise mess with until it breaks?

As always, help is always appreciated.

Garry