Got one head off - head & piston questions...?

[SeattleCharger]

Yup defiance, that's what I was asking, thank you.      Hadn't considered a stroker, . . .

[defiance]

What, wouldn't the heads do a pretty good job of stopping them???  





Thanks for the advice - I'll get 14cc valve reliefs (12cc works for 30 over, 40 over -which my engine is - needs 14, though ), a standard cometic .040" gasket, and deck it to 0.000" with the pistons.

Just to make sure I understand the reasoning there, let me explain my interpretation, and you can correct me if I'm wrong

Basically, quench is what makes closed chambers 'better' - it's the turbulence created by having the sides of the combustion chambers come very close to completely closed, forcing the air not only to compress, but to 'relocate' right at the end of the compression stroke.  It works best at very close tolerances, so you want your pistons to come as close to the heads as possible, BUT you don't want to get closer thatn .040" for tolerance purposes.

Thus, 0 decking with a standard .040" gasket is perfect for closed chamber heads, and I should use valve reliefs to snag my target compression.

Did I get that right?

[firefighter3931]

Basically, quench is what makes closed chambers 'better' - it's the turbulence created by having the sides of the combustion chambers come very close to completely closed, forcing the air not only to compress, but to 'relocate' right at the end of the compression stroke.  It works best at very close tolerances, so you want your pistons to come as close to the heads as possible, BUT you don't want to get closer thatn .040" for tolerance purposes.

Thus, 0 decking with a standard .040" gasket is perfect for closed chamber heads, and I should use valve reliefs to snag my target compression.

Did I get that right?

Yep, you've got the general idea. The tight quench forces the air/fuel mix into the chamber to be ignited and burnt. The loose quench engine will have the air/fuel mix ignite on top of the piston instead of in the chamber. This is what costs power and promotes detonation. Obviously, not all the air/fuel will be burnt above the piston in a loose quench engine, but enough of it will be to create issues, especially if the goal is to use pump fuel and make as much power as you possibly can out of the parts available. Most of todays newer engines use small efficient combustion chambers to maximize power with crummy fuel.


Ron