Josiah, the diesel topic.. :-) here goes ( promise to keep it very short ) : - precise tuned swiss watch mechanisms, use compression to ignite mixture. Diesels are 2 types, indirect injection ( the famous bedford lorries that go uphill on first gear and run out of breath if overloaded or the fiat trucks that managed 1 million kms mileage) and direct injection ( the famous monster isuzu buses that once roamed our highways at 100mph fully loaded with a unique engine braking exhaust valve system ). - Turbo diesel injection ( noisy engines ). Direct injection with lowered compression ratio, dome shaped pistons to create turbulence Extremely efficient engines and quality of our diesel has also improved. Engines suffer from blowby gases. These gases are impure and cause problems with inter-cooler and turbo bearing gumming. Turbo induction also creates hotspots within combustion chamber and correction to diesel impurities important. Correct engine oil is a solution, some even use synthetic. - Turbo diesel electronic fuel injection ( silent engines ). Very Complex engines. Extreme Oil pressure is the core. concept similar to EFI petrol engines. Isuzu 3.0 tdefi engines can have upto 6 engine management sytems. - Le Mans : Diesel competition engines are now getting better and giving petrol engines a run for their money. I could not resist this one so adding it. In my opinion, the world's most unique engine ever built but racing politics would kill its future development. JUST LISTEN TO IT, ALL I CAN SAY. 4 rotors giving 12 power strokes per crank cycle ( like a V12 normal engine ). No valves, no cams, no nothing. The engine revs with a feather touch of the throttles. Watch the guy in this video use a sequential gearbox. http://www.youtube.com/watch?v=K1BWv7iPFUg