ORIGINAL: Flyboy Dave

....it is odd to me that these bearing failures have occurred, especially on new, and
almost new engines. The front bearings are nicely shielded....and that in itself usually
provides enough added sealing at the front to provide for satisfactory operation.

Is it the bearing, or is it the clearance between the crankcase and the crankshaft in
the front rotor area ? Or is it the clearance between the outer race of the front bearing
and the crankcase at the front....or the clearance between the crankshaft and the inner
race of the front bearing at the front ?

The reason I wonder is because I ran the snot out of my first Tower .75 in a propjet,
and the engine ran pretty much wide open all the time....I certainly never babied it either.
I ran it for two years and then tore it down to check the bearings. They were in perfect
shape....in fact I put them back in to see how long they would last. They are still going
strong.

Maybe the fact that I use almost 50% castor in my fuel helps the longevity. Actually
our bearings only run at about half their rated capacity....they should last if they have
proper lubrication. Keep in mind, they are running without any heat to speak of, and
with a constant supply of fresh clean, cool oil. They should last a long time.

FBD.