Guys, don't know a lot about exactly what makes what happen with the spark system in exacting scientific detail, although I try to educate myself as much as I can on what makes an engine tick over nicely and what to look for in engine data to try and keep ahead of issues.
However I would like to share from experience in looking after our small fleet doing 3,000 to 4,000 hours a year combined, mostly all LOP and how spark plug health seems to effect our operations.
I read an article (about 5 years ago) on maintaining a good spark it made good sence and straight away I told our engineers to switch all aircraft at their next 100 hrly to all tempest fine wire plugs and every 100 hrly there after every plug was to be resistance checked and to throw away anything over 5,000 oms resistance.
It was an expensive exercise to change all plugs and the engineers thought I had lost it however within 6 months a few things happened that stood out. The aircraft average time of line dropped, our mag issues went away and we could get even lower average fuel burns LOP.
So don't acactly know the science behind why the mags are running happier although I have my suspicions but the bottom line is we seem to have much happier, efficient engines.
Maybe someone can touch on how plug health is related to mag health. The expense of switching to all fine wire and chucking what appears to be perfectly good plugs has been offset by sweet running mags and no more premature mag overhauls.
I maybe wrong but that's just what my data shows.