Hi and thanks for your comments!
@ gordonrobb
I would love some insight into how you got the texture (machine lines that are horizontal on the sides, and circular) on the piston. Also, the rough look on the underside. Care to share?
Its like learning a whole new way to texture.

I used different texture maps for the individual parts.
One radial anisotropy map (for the top) . And one linear anisotropy map (for the side). I used the maps (only) in the bump channel of the assigned material. This way octane renders them like a physically correct anisotropy material, where microscopic scratches in the surface (brushed surface) make the reflections look this certain way.
For the "rough look" I used the Octane Turbulence generator also in the bump channel.
Its not that difficult when you know how materials physically work!
I will not upload this scene but I hope that this gave you a little insight in the process!
Cheers,
Raphael