Riggle DOHC inline 4 Speedboat Marine Engine designed and built by Jim Riggle, ND, 1980’s
Jim produced his own patterns and molds for this 4-cylinder, water-cooled, DOHC mono-block engine. It sports pressurized dry sump lubrication, 2 valves per cylinder, a peristaltic oil pump, water pump, and fuel pump, and it burns methanol on spark ignition. Test results show it produced 4.5 hp at 15,500 revolutions per minute on a dynamometer. This engine utilizes two pairs of Jim's custom-built fully adjustable butterfly type carburetors and it is equipped for his radio controlled model boat. Previously he outfitted a duplicate of this engine for use in his Midget race car and both proved to be powerful contenders in the racing circuits.
Courtesy of Ed Miller,
Paul and Paula Knapp
Miniature Engineering Museum