earlwb

Well I have been using a old Fox Blue Head .60 engine (made circa 1967) on an on and it still runs good. It doesn't develop the power that a modern Schnuerle .60 engine does, but it is still running good. heck it still has the original main bearings in it. I did replace the rings in it though.
It even has needle bearings on the rod too.

So with reasonable care and barring some unforseen tragedy the Fox engines should have incredibly long lifetimes.

But yeah, I have killed a few Fox engines over the years. I did in a few engines pylon racing. Then I ruined a few engines trying out some free promotional 100% synthetic oil glow fuel when the fuel first came out. Then of course I have had the inevitable crashes that did in some engines too.

On of my old Fox Hawk .60 engines came close to ruining a cylinder, but fortunately the C-clip holding the piston pin in just scratched the piston on its way out without damaging the cylinder.  Those C-clips used on the wrist pins are one time use only clips. They need to be replaced each time it is removed. The C-clips are quite brittle and easy to damage. It could also happen at the factory when they put them together too.