Prototype Piston Award Signatures?

[Young1]

18500
I purchased this at the Carlisle auction.
18501
What is the significance of the the steel band molded into the skirt?
18502
Ray Cline? Chris Allen? What were these mens tasks in development?
18503
Rick Kuli?
18504
Gary Van Duster?

[grahambehan]

Steel inserts to help control thermal expansion.
Gary Cline, Chris Allen, Greg Vandeventer and Rick Kirk

Graham

[Matt B]

Steve, I can't contribute to your questions but let me say that this is DAMN cool piece!
Congratulations!

[staminqia]

Steve a cool piece!
I see you made it back to Florida! great to meet you in person.

Anthony

[WARP TEN]

A great find Steve! And thank you Graham, for your explanation. I have a piston from a '93 engine and I had honestly never noticed the little steel inserts until today after Steve mentioned it and I noticed just a bit of rust that has formed on the steel (after sitting on my deck for probably 20 years). A great bit of ZR-1 trivia. But I am curious: do other aluminum pistons commonly have such steel strips to adress thermal expansion or is it just the LT5s? --Bob

[grahambehan]

Thanks for showing pictures of the later piston Bob.
If you compare the earlier piston pics, you will see the subtle change in the piston casting to better support the expansion insert towards the pin boss, since the early ones used to break off at that point. Also the piston change to add an accumulator groove.
Cool stuff.
Graham

[tf95ZR1]

I never knew or noticed before either.
18515
My simple mind is trying to figure out how they'd help with thermal expansion.
Improved heat dissipation?

Sent from my iPhone using ZR-1 Net Registry (http://r.tapatalk.com/byo?rid=90383)

[Young1]

Per Grahm, steel inserts to control thermal expansion. This means they could have a tighter tolerance of piston skirt to cylinder wall to control slap and wear?

[WARP TEN]

Thanks for showing pictures of the later piston Bob.
If you compare the earlier piston pics, you will see the subtle change in the piston casting to better support the expansion insert towards the pin boss, since the early ones used to break off at that point. Also the piston change to add an accumulator groove.
Cool stuff.
Graham

Hmmm...they "used to break off"--scary. And yes this is "cool stuff", to mechanical geeks like me. But I must admit I had to look up what a pin boss was. Here are a couple of cutaways for other would-be piston nerds. Now that I look at the newer vs older piston pictures, I do see that the pin bosses seem to be a little beefier in the newer pistons. Still curious--do you know if other aluminum piston also utilize the steel inserts or is it just an LT5 thing? --Bob

[grahambehan]

Bob, Yes on cast pistons.

Graham

[WARP TEN]

Bob, Yes on cast pistons.

Graham

Thanks Graham! --Bob

[spork2367]

A great bit of ZR-1 trivia. But I am curious: do other aluminum pistons commonly have such steel strips to adress thermal expansion or is it just the LT5s? --Bob

At Lycoming, for our air cooled aircraft engines, the pistons aren't machined round, they are ovals and they taper from top to bottom. That way when they expand at operating temperature they are round. The bigger problem isn't that they expand, it's that they don't expand uniformly due to the increased material around the piston pin towers. Our pistons are machined from forgings.