OMC’s 4-Rotor Wankel Racing Engine - The Real Story
As told by John Sheldon
Former OMC rotary engineer
PREFACE
After the successful introduction of the 35 HP and 45 HP air cool/charged cooled snowmobile engine, OMC started working on water cooled/charged cooled variants of the same engine. Basically all the parts were the same except the housings, which were water cooled. Contrary to previous OMC, Curtis Wright and Mazda water cooled engines which had the water flowing axially; parallel to the crankshaft; these engines were partially circumferentially cooled. Water entered before the spark plug, ran around the rotor housing and exited around the exhaust port. The side housings picked up water at the entrance point for the rotor housing, travel across the hot section of the housing and exited at a low pressure point after the exhaust port. Both single and dual rotor engines had been prototype and development work had begun. The single rotor produced 50/55 HP and the 2 rotor produced 110/120 HP. The increase in HP was due to the improved volumetric efficiency (increased air flow) due to the lower temperatures resulting from water-cooling. Both these engines were configured for outboard use and were coupled to current lower units. At one board of directors meeting the twin rotor engine was mounted to a boat for demo rides. The tachometer was disconnected and the engine was left running. Every one that got into the boat turned the key to start the engine. There was no noise, no motion, no vibration. It was impressive.
Thank You, This Is What Brf Is All About
As a long time St. Louis resident and fan of the "St. Louis Race" for many years, unfortunately we had to miss some races because our PRO Nationals were on the same weekend. Th race where the Rotaries were run was one of those we missed, and it is really great to hear what happened from someone on the inside. All the crashes and "driver instructions" were evidently the reason the next year, a number of boat racers from other categories were used as turn judges at the OZ World Championships. I remember hearing there was controversy at a previous race for overlap violations, etc., and they wanted turn judges who had no connection with OPC racing or either of the factories. Now we have more of the "rest of the story".
Thanks again for all the technical info on the engine. The average person would probably never have had an opportunity to hear about this if not for you and BRF.
there was another company...............
Infinite Engines that used some stuff from moeller, there was a few of us old OMC guys workin there, they actually had 3 prototypes running, one was in a Boston Whaleer jet boat, one of the early modified OMC versions was in a polaris SL750 hull,, and the final one went into a Sea Doo hull, i beleive we were only getting maybe 60hp per rotor also... one thing i did and they closed down before it was run, made a 3 wall ex pipe, keeping the inner pipe hot and not cooling with water.....unfortunatly it didnt get enuf testing, i heard that sea doo still has that somewhere...........the whole program was based on being more emission friendly.........the problem is i think that its just not run of the mill technoglogy and its not been accepted, i know rotor seal technology has improved alot, ive always wondered how that 4 rotor would do in drag racing, the power curve is in the right place............Keep this rollin Ken....its always good to see kewl stuff