Relocating the camshaft to the exhaust side also opened up new options in positioning the spark plugs and fuel injector nozzles.It also locates the camshaft lower in the chassis and offsets its weight to the left side of the car, which can be advantageous to handling.The innovative design of the new Chevy Midget racing engine is the product of imaginative thinking and advanced technology.The USAC Midget rulebook embraces a wide range of engines that includes four- and six-cylinder powerplants, two-valve and four-valve cylinder heads, and overhead-valve, single overhead cam, and dual overhead cam valvetrain designs.“The Chevy Midget engine is a clean-sheet-of-paper design,” said GM Racing director Mark Kent.
Though the special event carries no points toward the season championship, it has quickly become one of the most coveted races to win.
While many series have adopted rules that tightly define virtually every component and dimension in a racing engine, the USAC National Midget Series offers engine designers the freedom to innovate.
The opportunity to think “outside the box” is the kind of challenge that GM Racing engineers relish.
The opportunity to design an all-new Chevy Midget racing engine was an invitation for some of our best and brightest engineers to create an engine within the USAC guidelines that would be competitive in both performance and cost with existing engines. ’ factor with the new Chevy Midget engine – every component is recognizable, but they’re repackaged and rearranged in a very innovative way.” In accordance with USAC rules, the Chevy Midget racing engine displaces a maximum of 166 cubic inches and burns methanol fuel.
The inline four-cylinder aluminum block has dry iron cylinder liners, and the aluminum cylinder head has two valves per cylinder operated by pushrods and rocker arms. “Creating an overhead-valve Midget engine by cutting off one cylinder bank of a V-8 engine positions the camshaft on the intake side of the engine,” explained Dennis Weglarz, manager, GM Racing Powertrain.