What's Quench?

I read and try to learn- and I see questions asked like, "does it have quench?". What does that mean?

http://www.moparts.org/Tech/Archive/motor/3.html

pictures! (at least that's what helped me finally understand it )

https://board.moparts.org/ubbthreads/show...vc=#Post5175716

Right it can be a help,just not a big HP gain. Low rpm with more comp than octane is a good situation to maximize quench. My current engine builder/machinest as well as others that make big HP don't find much HP with tight quench. A street engine with low RPM detonation resistance is a perfect place to be set up with tight quench.

Quench is what you get when the piston is less then .060" from the combustion chamber. The fuel-air mixture is squeezed out at high velocity from the areas where there is quench and helps to prevent pre-ignition and promotes a fast even burn.

On an open chamber head, quench is very difficult to achieve due to the manufacturing (casting) variances and rough surface of the chamber, plus the difficulty of finding a piston that would match the chamber perfectly. Some quench may be achieved around the edge of the combustion chamber where the chamber is smaller than the bore.

Compare the above to a Magnum or aftermarket small chamber head with a flat surface that extends well within the bore making it easy to achieve quench with a flat top piston. With a quench distance of .040", a compression ratio of 10.5:1 can be acheived on regular pump gas if the rest of engine is built to take advantage of it.

Engines with lots of quench also don't need as much spark lead as do open chamber no quench engine builds as the mixture burns more quickly and evenly.

Ramcharger Info:.

Here's a great article to read:

http://kb-silvolite.com/article.php?action=read&A_id=39