If the bolts were fine with 130,000 miles while in the car, and one

failed after a

proportionately much smaller number hours in the airplane, it must have

to do with

the airplane environment, not the age of the engine.  After reading the

posts

regarding this incident, I don't recall anyone discussing vibration very

much.  I

suspect that the engine, direct-drive and propeller - as a powerplant

system - has a

somewhat different set of vibration characteristics than the engine had

while in the

car.  It is likely that in the vibration spectrum for the powerplant

there is a

component which matches the natural resonant frequency(ies) of the

tension bolts,

while they are under tension in the installed condition.

Rob Weinstock wrote:

Was the engine balanced during assembly?

Regards,

Rob

I am sure it was Rob. Ran 120,000 miles in a car. Far as Perry knows
and from the looks of it it is right off the showroom floor plus 120,000 miles
and 200 hours as an aircraft engine.

Paul Lamar
 
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