The piston to wall clearance too tight or was out of round..
Heats up, pin becomes loose and walks out of the pin bore.
Scenario 2
Hell, I can't think of another plausible scenario.
Man, I'm sorry...I have so many different ideas/reasons flying through my head. Without having my hands on the parts and looking at them can I only speculate.
Crap like this is what I do for a living...yet only works when you can see for oneself and measure bore, journals, check pistons etc.
I learned a VERY valuable lesson a long time ago.
If you have an issue with an engine when it fails...tear down and rebuild the entire block. Don't mix/match pushrods, rods, pistons. It's like putting a crank in a block that you had to scavenge main caps from another block because you lost the originals.
You just can't use caps from another block without checking the alignment of bore. Can it be done? yes..will the engine last long? maybe...but I doubt for long.
Point?
If you throw a bearing but did not damage any journal surfaces...replace ALL the bearings. If you throw one rod bearing, replace ALL of the rod bearings. Hell, I would tear down the whole engine..and sanitize the whole thing..but you can get away with cleaning and soaking the block and just replacing the rod bearings. Is this proper or correct? depends..
Off my soapbox.
Advice? Measure twice, cut once.
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1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.
