w30442

If Quench is most effective with wedge style chambers and flat top pistons, what about Olds dished pistons design.

If you have a chamber head say 70cc or less and flat top pistons and pistons located down the hole to give you a decent compression ratio. Would this be a better design as compared to a larger chamber, tighter deck height and Olds dished pistons ?

If both scenarios gave you the same compression ratio is one better than the other. A dished piston would not have much or any squish compared to a flat top pistons but the pistons would be down the hole more.

Maybe I'm over thinking this.

cutlassefi

You are kind of. Most dished pistons still have a decent amount of flat or “squish” area.
Best combination is a shallow chamber with a dish in the piston. That puts the flame front more in the piston where it belongs.

w30442

Thanks for you input cutlassefi, Everything I have read says to run tight deck clearances for better squish for more turbulent gas mixture and give you better chance at less detonation. I was thinking Dished pistons would give you less of this but a flat top would be better but perhaps it will not be tight enough over the entire surface area and using the cylinder as part of the combustion chamber

cutlassefi

On a stock Olds combustion chamber you have very little actual squish area, as they’re quite flat and open. So the flat area around the dish in the piston more than covers that.

DROLDS707172

Kind of like a diesel engine, the head is completely flat and the chamber is in the piston.

cutlassefi

That actually has more to do with the valve angle than whether or not it’s gas or diesel.