Peened pistons
 

Facelift MT models have (except Europe) peened pistons.
What are they for? More resistance? Less friction?

Shot peening improves fatigue strength.

This explains it pretty well. It has pikturs too.

http://www.superstreetonline.com/how...-wpc-treatment

Shot peen, cryo, micropolish. Parts still break lol.

I've not heard of pistons being peened before. Only rods. You learn new stuff every day.

Sent from my SM-G973F using Tapatalk

Perhaps we're misunderstanding and someone in manufacturing gave them all a nice mushroom stamp for QC

In the speed shop i work with they have tried it all. They still use cryo and dicronite as the main treatments for specialty engines. Shot peening had inconsistences that made it unreliable. Good suppliers of parts for high performance engines seems to be the most reliable way to build an engine.
I am sure that many of these prosses help, i can only talk about our shop experience.

Me either. Especially a part that needs high quality finish machining like a piston.

There are no guarantees lol.

Yeah, you'd never peen the skirt or the ring lands right? Surely it'd be too rough. And are broken pistons that muchbof a problem?

Sent from my SM-G973F using Tapatalk

We tried putting a light knurl on the piston skirt and applying millennium disulfide. Very labor intensive and theory was good but we could never prove its worth.
Racers will try anything twice if you think it might give you an advantage.

haha... molybdenum not in dictionary, or only available once every thousand years? Anyone interested in my executive summary of what shot peening does on a molecular level?

Yes


Sent from my iPhone using Tapatalk

Ball bearing races last as long as they do because they are shot peened before they are ground to final shape.

It's another form of work hardening. All metals solidify as disorganized seeds of highly organized crystalline structures. Those grains grow into each other and remain attracted to each other less tightly than the crystals themselves. they can be displaced from each other only a certain amount until they slip and don't return to their original positions before the force was applied.

The further these grains are displaced from each other permanently, the more force it takes to reach the point where they slip again. This only goes so far before the bonds break down, but up to that point, the material is harder than it was before it was "bent."

Shot peening bends all the grains near the surface but leaves the layers underneath at rest. This increases the hardness of the surface layer relative to the desired hardness of the base material.

I heard the 13 valve springs were made from a material developed from ufo wreckage. Unfortunately there was a reason it wrecked.