Thomas Borchert ) wrote:

And the cylinder heads? For the higher powered engines we have, a top
overhaul after 400 hours is nothing unusual at all. With a 1800 or so
hours TBO, if that ain't broken, I don't know what is.

The IO-520 that was just removed from my Bonanza got somewhere around
2400 hours on it before a small crack in one of the cylinders put the
first and last nail in the engine's coffin.

Prior to the crack, the cylinders were all still producing excellent
compression ratios. As far as I know, no overhaul was ever done on
them. BTW, these were Continental cylinders manufactured in the late
80s.

I certainly do not expect to have to perform a top overhaul on the new
engine's Superior Millennium after 400 hours.

--
Peter