Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Actually when it comes to high rpm the connecting rod is literally pulled apart from higher RPM. The forces are much higher than the explosion forces even with detonation the rod is literally pulled apart at higher RPM if you exceed the designed rpm speed limit.
 Piston speed is actually quite high changing directions at top dead center compared to bottom dead center it is relatively low speed changing directions.
 At the speeds these engines run one oil hole would be enough I believe whether it’s at the top or the bottom.