About this 3D model
All parts have to be mirrored to fit correctly on the buildplate. Printed all parts on my Ultimaker original, layer height 0.15mm, top/bottom/wall 0.8 mm, speed 70 mm/s, flow 110%, fill 20%. Adapted the movable engine from http://www.thingiverse.com/thing:50988 to a 4 cylinder engine. used gears http://www.thingiverse.com/thing:6544 scaled to the project. got a solar powered motor from www.conrad.nl