Bad coil?

1st : Inspect cap rotor and connections in dizzy and on the coil

2nd:  Key on and test + side of coil to confirm voltage

If you are by yourself,  you can run a test lead from the starter solenoid  and with car in neutral and key to on, touch the test lead to the B+ on the alternator this will spin the motor over.

Crank over the engine, and there should be a nice blue spark that goes from the end of the wire you pulled out of the center of the cap to the metal clip. It should look and sound strong, and should be easy to see, even in daylight. If it looks thin and weak (yellow is weak, blue is strong), then the coil windings may be giving out.

Another test for the Bosch Blue coil, is to use an Ohmmeter and with all the wires taken off the terminals of the coil attach the positive and negative, red and black, wires of the meter to first the terminal 1 and 15 that are printed (stamped) on the coil. You should have a reading of at least 3-4.5 ohms, which is the resistance reading inside the coil. A bad coil will show a higher reading then 3-4.5, you want less resistance.

Next, place the red or black lead from the meter to the center of the coil (secondary post), and to either one of the terminals, again 1 or 15 on the coil. You want 9500-10000 Ohms, sometimes you ll see less, but you don't want want to see something like 11,000. Or if you have no reading in either case, the coil is NG.

...Stay dry with the pending storm ~

Thanks.

I will try a few of your suggestions when the rain lets up tomorrow. 

I've also had a bad chassis/ trans / engine ground do this and it didn't make a lot of sense as other electrical worked ok

Grounding on the old VW chassis when used on the VS is a nightmare due to rusting. I've seen that lots of time.

I had a similar failure when a distributor rotor failed and came in contact with the cap, ruining both.  Not sure exactly what caused the failure, but the fix was easy.

Oops!  Reread the initial post where you replaced the Magnaspark.  You’d have noticed the rotor failure.  In the immortal words of Ms. Emily Litella, “Never mind.”

Grounds: Confirm good ground from neg on battery, ground connection from trans to chassis & add another wire from the alternator case to ground

mine shut down once. it was a loose connection from the dizzy to the coil, it was the connector that attaches to coil,,a tender squeeze with pliers and good to go.

Coil tested bad.

Ordered a new one from CB Performance that mates to the Magnaspark.

Odd thing is NAPA had one that looked exactly like the one that CB has but according to both specs NAPA'S had a lower primary rating by about 20%. It is an odd coil so I thought I would stay with what I thought was their style.

I had a NAPA one in it when it quit running.

Could that have been the issue? 

Does anyone know if Kirk used the oil or epoxy fill Blue Bosch coil? I was reading the oil filled have a 7.8 Ohm secondary and epoxy filled 8.4 Ohms- not sure of the effect on my distributor with the CompuFire?