Plastic pistons.

[GR_CoB]

Needless to say, didn't last long

Here is the video, engine starts after the 6th minute mark. (sorry, it's in Russian, but I'll post a link when English translation comes out)

 

[wwillson]

Sure seems like a lot of work for an inevitable outcome.

 

[Eddie]

Many years ago a plastics company made a complete engine from the thermo plastics they manufacture. They ran it and it did surprising well but, I forgot the details. Maybe someone else remembers. Ed

 

[Greasymechtech]

Plastic cams worked well too

 

[4WD]

Plastic cams worked well too

Plastic gears are great too … but the secret is Lucas oil additive

 

[earlyre]

https://www.automotiveplastics.com/blog/you-wont-believe-this-a-real-plastic-engine/

 

[ecotourist]

It's a nice looking shop but don't let him talk you into an engine rebuild using wooden or plastic pistons. Unless you like smoke.