ORIGINAL: enormydude
And in the process turns the wooden Bolly 28x10 into matchsticks and sprays the debris up to 30m away!
I've read a whole bunch on several forums where prop bolt failure is often the root cause of throwing props. The thing here is I don't see how throwing the prop would make the engine stop dead still from 6k+ rpm instantly. I think the sudden stop is what caused the prop to shatter and depart, tearing off all the bolts in the process. But that would point to detonation or maybe pre-ignition.
Ofcourse the crank was bent after that but was not obvious until the crank case bolts were released and the engine turned over showing a wobble between the front / back case interface.
I'd love to hear any thoughts on this one. Especially any experience with motors stopping dead still. Scared the crap out of me I can tell you!
Norm.
I don't see your inspection results on the bearings and crankshaft surfaces. What were they like? And the connecting rod and wrist pin?
An engine doesn't just stop, and a crankshaft doesn't just bend. From your description, I would be inclined to look for a flawed fillet in the crankshaft (subsurface inclusion? Machining flaw?), and a resulting crack, with distortion looking like a bent crankshaft. If that's not the case, there should be a seized bearing or wristpin bushing, or something that caused the abrupt stop.
Let us know what you find.
Dave Olson