I did a search, but couldn't find anything good.

Is there a technical article or something out there explaining the shape of pistons? I'm talking about the top. I've seen some Endyns that are flat, my JE's have a pretty deep "valley" in them. What does this all mean?

Or can anyone explain it to me? Thanks.

 

a dished piston will yield a lower static compression ratio, while a taller domed piston will give higher static compression. also some piston designers like to design the piston to act on the mixture in the cylinder with such methods as pushing it to one side or the other, or squishing it toward the plug, etc...