One more question about the iridium plugs. Can you clean these by
bead blasting just like the standard plugs, or is the iridium coating
fragile?

Mike,

 

I don't know how others clean their fine wire plugs but, because of the "fine wire" and its itsy bitsy tip, I just use a brass brush and acetone plus a home built probe to dig out the deposited globules down deep - then blow'm dry with compressed air.  There is not much to these electrodes and blasting might do more harm than good.  I am sure that you have noted my use of highly technical terms so far.

 

I schedule a cleaning about every 50 hours as the bottom plugs show more deposits since I still have to use oil in the engine.  Also, I am using the LASAR "electronic" ignition system and the plug gap is maintained at about .018 - theoretically so that the backup mag function's spark can successfully bridge the gap.  Other true electronic ignition systems prefer that the gap be larger - quite a bit larger.   If you buy such plugs directly from the manufacturer (Champion?) they seem willing to specifically gap them for you at the larger gap with their special equipment - at least that's what my friend with the blown Lyc in his E-Racer told me.  After all, they are expensive and the "fine wire" electrode is more fragile than the massive electrodes in the standard plugs.

 

I don't remember how many hours (or years) ago I started using them without referencing the engine log, but there is no indication that any visible wear (molecular erosion) has taken place.