Lynn was that small gap WITH a MSD system?

Bill Jepson

The-115 plugs come with a gap of about .018" to .020". The retracted gap ground electrode is welded flat on the end of the plug. I just tap the ground with a screw driver tip, to close it up a bit. You need a wire loop type gage to check it.

 

Once, while the car was warming up, I thought I saw a plug boot backed off a rear housing plug. I grabbed my giant straight slot screw driver, and using the frame tube as a fulcrum I pushed on the boot, while being careful not to touch any part of the car or the driver shank.

 

The boot was all the way on, but before I could remove the driver, an arc jumped from the driver shank to my wrist watch. About 2 inches. 

 

I dropped the screwdriver. I sat in the grass slowly removing my watch. That hurt my pride, my arm, my wrist, my shoulder sockets and the balls of my feet.  

 

Less like being shocked by a plug wire from the lawn mower, and more like being hit in the head with a ball bat. I offered myself as a very high resistance parallel path around the plug gap. Didn't matter at all to the excess energy available.

 

I have two stents now, and just watch things. Never reach in to do anything with the engine running.

 

The MSD will fire once when you turn it on, and once when you turn it off. It needs a short gap to jump when this happens. Either a grounded plug or a gap to ground, under one inch.

 

Lynn E. Hanover