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TR4/4A Busted crankshaft

The main cap went after the crank died because of the severe twist it was subjected to. Note the break started right along the journal corner...if you had a close up, I have no doubt you would see the fatigue beach marks fanning out from a point along the journal corner. Also, that is a steel part, as a cast crank would have a larger, dark, crystalline area at the break, instead of the shiny surface from extensive rubbing as the crack grew.
 
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