Originally Posted by birkey
I cant remember where i read this, but someone said that a dished piston with a properly designed combustion chamber can promote better flame travel than a flat top. is this all talk or is there hidden science behind this theory? do valve reliefs affect combustion at all?
If your talking about chevy sb heads for the most part no. But if the head is very flat they can make the combustion chamber in the pistons. But not needed on chevy motors. Flat tops are best for small block chevy. Other engines need different pistons to promote good travel. Hemis need pop up pistons to push the fuel/air mix into the top of the chamber to promote good flame travel. This usally just means pushing all the gases right up against the spark plug area. Inside a pocket giving the proper compression.
Yes and no on the valve reliefs. If they are sharp they can promote detenation. Smoothing them over a little just to break the edges is normal. But they do not effect flame travel. Some swirl devices do Sometimes but are designed to work with this in mind.