I intended to write:

There are the exceptions that give us hope and the most notable exception is the Teichert diesel. Why has this engine succeeded where so many others have failed?

I should also have pointed out the Rotax and the Subaru conversion. Although the Subaru is a direct descendant of the VW Beetle engine, itself derived from an aircraft engine. Talk about the "circle of life".

Before I get hammered with this or that specific example I would point out that for every success story (none having passed the certification testing Rubicon) there are 10 or more failures. Not good odds for the aspiring engine installation designer. My dusty stack of old Airventure program guides are replete with engines that have faded from the market.

Regards
Brent Regan