Printed 7/20/2018. Had a little trouble with the bolt hole support on the block (used a heated soldering gun to correct them manually). Also had trouble with the piston pin staying in. To make everything stay fitted while turning the crank, we placed a little glue on the piston pin, and used another washer on the back side. So it is held securely, can spin quickly, and does demonstrate the concept of intake, combustion, and exhaust. Mix of PLA (red) and ABS.