The engine pictured above is Replica Engines' latest - a recreation of the racing version of the Oldsmobile Aurora V8 that General Motors built for the Indy Racing League. Without access to engineering drawings, the model motor was painstakingly reverse-engineered from a full-sized unit.
More after the jump... The miniature aluminum block V8 displaces 3.8 cubic inches, with a .915 inch bore and a .723 inch stroke, and features dual overhead cams running four valves per cylinder, a 15: 1 compression ratio, mechanical fuel injection and a dry sump oiling system. The engine runs on methanol, just like the original.
In order for the scale engine to be fully operational, some of the internals are not to scale, such as the Aurora engine block's internal oil passages, which would be too small to flow enough oil at their true scale diameter of .063 in. But functionally, the engine is faithful to the original design, with oil feeding through the engine block to the crankshaft and to the four overhead camshafts. The hollow camshafts pass the oil through while feeding oil to the cam-bearing surfaces cast into the heads. Oil then siphons to the bottom end.
The laws of physics also intervene in scaling down the ignition system, where the model engine's twin distributors are slightly larger than scale to prevent high-voltage arcing across the terminals. (By the way, the distributors feed handmade steel and ceramic spark plugs.)
Other model auto engines built by the Warners' company include a 1940 Offenhauser, a 1937 Harley "Knucklehead" V-twin and a 1937 Ford 60 flathead V8. (Videos of the Offy and the Harley - running - are here.)
The Aurora V8 is being built in a limited edition of 100 units, with a complete engine setup, with test stand, chrome headers and ignition coil, running just under $10,000.
[Sources: Replica Engines, Machine Design] Thanks for the tip, Gary!