This is updated version of my mini engine.

This one is scaled ja bit bigger. It has sturdier pistonrods, longer stroke length. It also has somekind of head gasked, head and cover.

I suggest to print it without head gasket, head and cover. Head goes really easily bonkers, i fiddled several prints with various options and in various ways, it has to be just right to get it done.

Everything is but together just snapping, no need for glue or anything else, it's designed to need only printing and assembling, and it could be dissassembled also.