Scott:

** I meant that you will always comment that in some way anything other than mags leads to engine problems. And, it is always general so that the reader could only conclude not to try existing experimental products for fear of something bad happening to their experimental airplane and experimental engine. **

I don't think I have done that.  I, too, am looking forward to getting rid of my mags. There are some things about electronic ignitions and plying with timing that can present problems. That has been the thrust of my comments.

**Given the coarse hand controls we fly by - throttle, prop and mixture - It would be nice to hear practical information on how we could use "data" from the crummy engine monitors we have (no pressure monitor) - GPH, CHT and EGT - to determine the quality of the engine operation.  Those of us leaping into a pit of lions by installing advanced ignition systems generally see positive results - higher horsepower felt in the seat-of-pants dyno, fuel savings at lower power settings, easier starts and higher speeds.  We also see lower EGTs and higher CHTs, all explained in the product sales brochure. **

Lower EGTs and higher CHTs are compatible with advanced timing as I have alluded to. These are not positive changes in my mind and are not compatible with longevity concerns. Seat of the pants dynos have been known to be waaaay out of calibration. The measured HP does not change significantly with changes in timing at high power settings. The stress on the engine does. And, that is independent of how the spark is generated.
 
**Well, a Google search using: crankshaft harmonics electronic ignition aircraft engine 
did not turn up anything.  **

As expected. There is only one source for that information and they are holding it as proprietary at this time. I was quite certain that you, nor anyone else would have known anything about those issues. It does not change the fact that there are significant effects of the law of unintended consequences in varying ignition systems that have been noted by researchers who have not yet published the findings. The point is that this i, indeed, an area of an experimental nature. For example, as noted above, the lower EGTs claimed to be a good effect of EIs is NOT a good thing. It's the result of an alteration of the effective timing.
 
**The facts don't upset me at all.  Indeed, some electronic ignitions do provide for a retarded spark at high power settings.  Usually, us experimenters make the comment "Gee, takeoff works better with a retarded base timing." This seems to be the case on a NA engine with CRs greater than 8.5.  If only we could measure this - even indirectly with the current engine monitors.**

Ah, but you CAN. If the EGTs went UP and the CHTs went down after a timing change during takeoff, it would tell you that you have retarded the effective timing.
 
Again, still waiting for the reference on why the reduced combustion mixture pressure achieved at higher altitudes where WOT yields MAPs below 21" would require greater voltage to arc the plug than that required at sea level where the MAP might be 30" (same compression ratio).
 
I corrected my mistake in another post. I also thanked the person who pointed out my error with a reference. I guess you missed that.

Walter