Well...... it really sounds like you did everything correctly. Its hard to say what caused the failure. I understand your frustration though. We overhauled a motor last year, it didn't make it 200 miles and spun a rod. Tore it down and could not find any reason for the failure. Sent the block and the crank to my regrinder just to see if he could find anything that we didn't. He told me it was a perfect rebuild. We labeled the failure as "block contamination". Our assumption was there was metal or dirt that was stuck in an oil galley. I have overhauled/rebuilt over 100 engines in the last 15 years. It was the first one I ever had that failed. So, sometimes, even when you do everything right, something goes wrong. Tear your motor down, you may find that is was just a freak or even a part failure that had nothing to do with you.
