[Xrati]

I saw a picture of that engine block 5 years ago. Being a toolmaker and working for a Division of GM at the time I can tell you this. While the engine block is a plastic composite, the moving parts are still metal (inserts, sleeves, bearings). The block is cooled by a unique 'heat-sink' system. There are 6-8 cooling lines running parallel to/on each cylinder. The plastic composite is forged using carbon based material that can withstand heat ranges of an operational engine. The 'casting' is machined as a metal block would be. The biggest problem they were having back then was warping, due to the torque load! AND that was five years ago. I have not seen any recent info on the progress, but I'm sure that with newer materials available, it's probably very close to becoming a reality.