hello Chaps Recently I have been modeling on fusion 360 a Kiwi by the great ETW. (to take to one of my local foundries to cast for me, due to the cost of the shipping the Hemingway kit, to Australia being truly ridiculous. and because my parents do not like the idea of me messing around with molten metal.) but in a fashion of which I am intrigued and interested in further developing, trying to make it an ether-less diesel that is mentioned here http://www.modelenginenews.org/gallery/p8.html on Ron's great website. I have a few tricks up my sleeve in improving upon the one mentioned in the link that was built by 'Malcolm Beak'. I have already significantly 'beefed' up the conrod, crankshaft, cylinder thickness, head bolts, and the cylinder bolts. The first one of the improvements I have thought of was making it air-cooled instead of water-cooled like the one in the link, and make the cylinder, piston, and head entirely out of cast iron, due to its lower thermal conductivity to help retain heat in the combustion chamber. My other thought is to make a copper part that will screw onto the face of the contrapiston, so it will conduct the heat created by combustion, and be a somewhat 'controlled' hot spot to aid the ignition of the compressed charge, but will be easily moved away from the combustion chamber to prevent detonation whilst lowering the compression ratio and make it 'less accessible' to the compressed charge. As always all comments advice and suggestions will be greatly appreciated! Because the only way I have gathered the knowledge that I have is from the help and advice from those who have greater experience and knowledge than me. Thanks Greg.