"Billgran" wrote in message
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"Del Cecchi" wrote in message
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I understand the reasons pro and con for forged vrs cast pistons for
automotive applications. It just struck me as a little ironic that
after all the "discussion" over lean burn and detonation and high
temperatures and all that, that this press thing touting the NASA
alloy use came out.

I had a little trouble figuring out how this alloy is different from
other silicon containing aluminum alloys that folks have been making
pistons out of for years. But that is a press release for you. I am
sure there are differences, but it can't be figured out from the press
release.



The lean burn and the detonation "static" is only from the karen down
under, not from those who are familiar with the engines and work on
them on a daily basis.

You can feel the difference in the NASA alloy compared to an ordinary
piston. It is more dense and scratch resistant and has a different
"feel" when you heft an E-TEC piston. One of the biggest reasons is the
more controlled expansion so the pistons can be fitted tighter in the
cylinder for less "slap" which results in a much quieter motor. That is
one of E-TECs strong points, at cruise and WOT, it is about the same or
even quieter in some cases as a 4-stroke.

Other companies are using the NASA alloy for a number of uses,
including pistons and engine block castings.

Del, you did see that I added a to my previous post when I asked
why not have only one type of piston, right?

Bill Grannis
service manager

yes I saw it. And you saw i put "discussion" in quotes, eh? But it did
strike me as sort of funny.

And I saw the page about the alloy. Sorry, not being a metallurgist I
can't tell truth from fiction.

del