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Old 03-26-2006, 05:33 PM   #14
Les, slight limp
Board Member
Join Date: Sep 2005
Location: clayhanger, uk

I cut the main grooves more or less level with the bottom of the combustion chamber in a straight line to level with the top of the squish area about 3/16ths in from the gasket ring, i'm afraid the first one on number one piston area got a bit close to the ring and i was a bit more careful after that, the smaller grooves are about half depth.

As i see it (just a theory you understand) the walls of the combustion chamber act as a barrier to the flame front, tight squish improves things by leaving less unburnt fuel in the squish area and so reduces the chances of detonation, the grooves actually encourage the flame into the squish area leading to a more complete burn and that's why the squish clearance needs to be around 70 thou so there is enough fuel in the squish area to provide a consistant burn, otherwise a clearence of 70 thou would actually aggravate the engines tendency to detonate, alternate theories welcome.
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