Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - standard dish vs d dish
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Old 01-10-2013, 05:18 PM
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What I try to recommend is a piston that has a sufficient amount of flat area on the crown that it will be able to "squish" the mixture (that would normally be in between the piston crown and the underside of the cylinder head), across the chamber, creating turbulence and homogenizing the air fuel mixture in the chamber to help insure complete combustion of the mix. Building a tight squish (0.035" to 0.045" on a SBC) will also help to prevent detonation and may allow the motor to operate on a lesser grade of fuel than if you didn't have a tight squish.

If a fellow has to use a dish at all to reach the intended static compression ratio on his build, I prefer the "D" shape of the Keith Black pistons. They have a generous flat area on the crown to generate the proper squish at close to TDC. Pistons that have circular dishes generally don't have enough flat area on the piston crown to cause the mixture to "squish" across the chamber.
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