Here you go, Piston area and force.

Dale
You are 100% wrong in post #125, with 'PSI spread over a larger area creates more force'. Look at post #130. Pressure = force divided by area. The force or pressure [ or whatever you want to call it ] is created by the expanding gas. I used an example of 1000 what-u-ma-call-its. Call it what you like & whatever quantity. The point is that the loading per sq in is less on the bigger piston even though both small & large pistons had the same initial force/pressure applied. That is what the picture in post #130 shows: the flat coin did not sink into the plasticine as it did on it's end because the loading per area was less even though the same initial force was used.

I have already given this example, but maybe you missed it. The piston transmits it's load to the crank via the pin & conrod. If I make the rod eye wider, according to your theory, because I have increased the area, the rod now transmits more force to the crank & the engine makes more hp!!!
Increasing the area of the piston should increase the weight of air drawn into the cyl. If it does that, then the pressure generated from the burn has increased. It is this increase in gas pressure, not the piston area that has created more force.