Here’s a pressure-puzzle for you: Inside the combustion chamber during a WOT power stroke the burning gases can momentarily exceed 1500 psi. With a three-inch bore and so a seven-square-inch top surface, the piston transmits over five tons of force down the connecting rod. The bearing surface between the connecting rod and the crankshaft journal, however, is barely three square inches on many engines, and only about half really supports any load. This makes for a unit pressure between connecting rod and crankshaft throw as high as 5000 psi. Meanwhile the oil pump only puts out perhaps 50 psi. Why don’t we have metal-to-metal contact at every power stroke if there’s a hundredfold difference in the pressures? And if that bearing load is hard to understand, what about at the wrist pin bushings, lubricated on many engines by nothing more than splash?