Thread: squish clearances

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how dus squish clearances affect compression and detonation?

The idea behind squish is that it causes a violent "squirt" of air/fuel mix as the piston squeezes up to the head at TDC. This should improve mixing, combustion, and cooling of potential hot spots, allowing higher CR's. The only problem I have with the theory comes from my experience with old Hemi's, they have no squish area at all, and can run on much worse gas than anything else I ever saw and never detonate. Just one more case of the real world defying theory, I guess.

Originally Posted by R Pope

The idea behind squish is that it causes a violent "squirt" of air/fuel mix as the piston squeezes up to the head at TDC. This should improve mixing, combustion, and cooling of potential hot spots, allowing higher CR's. The only problem I have with the theory comes from my experience with old Hemi's, they have no squish area at all, and can run on much worse gas than anything else I ever saw and never detonate. Just one more case of the real world defying theory, I guess.

Probably because of the centrally located spark plug where all areas of the chamber were equidistant from the plug. That and a low surface to volume ratio which tended to eliminate cooler areas and lended itself to a complete burn. I'm just theorizing though.

Originally Posted by techinspector1

Probably because of the centrally located spark plug where all areas of the chamber were equidistant from the plug. That and a low surface to volume ratio which tended to eliminate cooler areas and lended itself to a complete burn. I'm just theorizing though.

i was thinking the same thing after i ran the post so i am going to be runing 9.5:1 how much is to much and how mush is to little?

Originally Posted by techinspector1

Probably because of the centrally located spark plug where all areas of the chamber were equidistant from the plug. That and a low surface to volume ratio which tended to eliminate cooler areas and lended itself to a complete burn. I'm just theorizing though.

Richard,it is no theory.
What you said is 100% true I.M.O.