MG Car Repair: 72 MGB starting problem, spark plug wire, bad cap

Question
My '72 MGM (inherited from my son) has not been used for about 5 years-stored in my garage.  Prior to that it did start and run okay.

Now, it turns over, has fuel and compression, but I only detect fire out of the coil (tested by removing the coil wire from the distributor cap and touching it to ground while the engine is turning over).  However, I get no fire from the spark plug wire when grounded to the block.

How can I determine where I am losing the fire between the coil wire into the distributor cap and the spark plug?

Thanks for your help.  I have read several other responses of yours regarding starting problems, but did not find my specific problem.  I did read your answers to brake bleeding problems and found them quite useful.  I had that problem years ago and probably will again.


Answer
Hi David,
That should be an easy fix. First remove the cap and hold the coil wire about an eighth of an inch from the center of the rotor and have someone spin the engine over and see if a spark jumps to the rotor. If it does the rotor is bad and the cause. If it don't then look at the inside and outside of the cap for any signs of "carbon tracking" which is an indication of a bad cap. If you don't find any tracking, check each plug wire with a ohm meter for a connection. Then check the spark plugs.
In that group you have to find the problem (if you had a good spark from the coil)(a thick blue spark that will jump at least 1/4 inch)
Howard