[NOTASIX]

After seeing scenarios like this unfold before, l have to say that “rapid acceleration” usually equates to failed clutches, as well as connecting rod bolt failures. From the outside looking in, it would make logical sense to me that at some point something happened that caused that clutch plate to break. The chances of whatever that was leading up to the ultimate failure being related are very good.

Remember the “50 hour rule” folowing an “engine zing”. l am not pointing fingers here, and it doesn’t matter who may have done the “zing”, as it would have clearly happened before it went to the last shop. Maybe there’s a piece of the puzzle that no one has shared?

For a “real” (not Chinese knockoff junk) ARP rod bolt snapping out of the blue are very slim on such a mild engine. l would have to question the torque value that was used when assembling the engine, as it coud have been either left loose, or over- torqued, resulting in this occurrence. Then how well the entire dynamic and reciprocating masses were balanced is another question mark. l have seen imbalance cause weird issues, especially failed clutch plates. A clutch plate is the first component that wil show signs of an over- rev, due to it’s mass, and it’s diameter being so large in comparison to the other components in the engine.

Likely a very good disassembly would find the issues if someone did botch the rod bolt torques. They probably goofed up more than one.. l like to figure things out like this, its pretty much all l do, all day long.

At the end of the day its mechanical. That means there’s only two guarantees:
-It will fail
-It will wear out, if it doesn’t fail first

My question mark right now is the clutch plate, and what caused that to fail. l’ve been using KEP parts like that for over 20 years, and the only time l have seen a failure was when something saw “rapid acceleration”. Misfires are also evil, and they can be equal to hitting the internals with a 10 pound sledge hammer. Driving a car misfiring badly could be another contributing factor. l’ve snapped a crankshaft on a track car shortly after repairing a serious on- track misfiring issue.

Not pointing any fingers, just putting in a question mark where l think it needs to be based on direct experience.