No worries here. You are correct I'm not an engineer, but I am an engine builder, and I do trust my teams decisions. Some more insight, we have a machine in the back called a crank breaker. I'm going to over simplify this, but it's basically a sound resonance machine that shoots sound waves at a crank, and you can physically see the crank vibrate. They have calculation relative to piston speed, stress on a journal, etc. You can physically see it vibrate. We over stress the cranks, see where they fail, and make decisions from there. It's quite a process.