Originally Posted by ian sibbert
No, not being clever, just I had 4 of them with me this morning and 2 of them were arguing its the piston dropping that causes suction which pulls air into the engine....
no, the piston dropping causes a drop of pressure, which causes a pressure differential which results in the atmospere pushing air into the cylinder.
its semantics from an english point of view, but physics is very fixed on its opinion of what happens.