Just for fun I 3D printed this at 5% and used some small pieces of wire and steel for bolts and shafts.. (they still need trimming)
Too small for many of the features to come out well, but it looks pretty good if you squint. ;-)
I'll try one at 10% and maybe find some little nuts to glue on.
Are there any other parts available fr this little engine, or was this just a test-piece?