what is the difference between floaters and pressed when referring to pistons? and what is hyperuteric ( i think I butchered the spelling).?

Caesar

Floating pistons have pins that can rotate in both the piston and the rod. The pins are retained by spring keepers.

Pressed type allow the pistons to rotate on the pin, but the pin is tight in the rod.

Don't worry, I had to go to college and take several chemistry classes to find out what hypereutectic means. Hypereutectic refers to the type of aluminum alloy used, and a hypereutectic piston can either be cast or forged. The aluminum in this sort of alloy has been mixed with another element in such a ratio that part of the alloying element solidifies before the aluminum and the rest of the alloying element freezes. A hypereutectic aluminum alloy will, if you look at it under a microscope, have tiny grains of its alloying element surrounded by a region where the alloying element and the aluminum cooled at the same time into a relatively uniform mixture.

If you're looking at how it behaves in an engine rather than under a scanning electron microscope, the difference is that cast hypereutectic pistons are a bit stronger than regular cast pistons. I am not sure if forged hypereutectic pistons are any stronger than forged pistons made from the alloys typically used for forging.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
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