Bullet Proof?

While chasing that philosopher's stone of general aviation, the "bullet proof" piston engine, I ran across this stimulating post on aircraft engine reliability.

Based on the data posted, I estimated the fleet-wide odds.  Over a 25 year period this is the rough-order-of-magnitude fraction of aircraft engines (including automobile engine conversions) that experienced catastrophic in-flight failure:

Lycoming:         1 in 1000
VW:                  1 in 120
Ford/Subaru:     1 in 30
Mazda:              2 out of 3
Chevy:              4 failures each

This is based on actual NTSB accident investigations back to 1985, compared to aircraft fleet sizes currently registered (as of 2009).

The truth is probably significantly worse for the Subaru/Mazda because there were very few flying before 15 years ago or so.  People have been flying behind Fords since the 1930s (Model A) and the VWs since the 1970s and maybe earlier.  Chevy enthusiasts have been trying to fly the "big block" engines but most have been using the Corvair.  I am disappointed the Mazda engines did so poorly here, because I had/have high hopes for the Wankel (rotary) engine.

The VW conversions actually come out looking pretty good.  The Aerovee slated for use in our Sonex probably does better than above because the data includes ALL Volkswagen derivatives.

The poor record of the Chevy conversions may be slightly overstated, but then again maybe not, because if the author's data is to be believed, apparently there are currently NONE registered (I cheated and divided by one).  The first thought that springs to mind is that they all must have crashed or scrapped!

As a postscript, I will add that the engines that I found most often mentioned as "bullet proof" are the Lycoming O-235 and O-360.  That's encouraging news for our Bearhawk, which sports the latter.