USAC Midget Engines - Chevy's New Midget Engine

We've often wondered what would happen if one of the heavy hitters in racing would take a lower-level, short track race engine and apply all those neat ideas they pick up in the top areas of racing. Think about it. Most of the big factories in Detroit have hard core racing programs. We see the results in Indy Cars, road racing, drag racing and, of course, NASCAR. Imagine what would happen if one of those factories applied all that modern technology to something like a Midget engine.

Well, we don't have to imagine. In a move that caught most of the industry by surprise, Chevy unveiled its all-new Midget racing engine at Indianapolis Motor Speedway recently. It was a big official deal with GM representatives and United States Auto Club (USAC) team owner Tony Stewart there to see it off.

"One year ago, Chevrolet announced its sponsorship of Tony Stewart Racing (TSR) in open-wheel competition," says Chevrolet general manager Ed Peper. "Now, Chevrolet has taken the next step by creating an all-new racing engine for this popular grassroots racing series. Chevrolet races to win and America's brand is aiming for more victories in this uniquely American form of motorsports."

The new motor was designed by GM Racing specifically for the USAC Midget Series. The purpose-built, four-cylinder Chevrolet racing engine will initially power TSR drivers Tracy Hines and Levi Jones in upcoming events. The new engine will be available to all USAC competitors through independent engine builders. As this engine is brand new, the demand will initially outstrip supply until they become more available to the industry.

"The Chevy Midget racing engine is definitely going to be an asset to Tony Stewart Racing," says team owner Stewart. "Having the Chevrolet bowtie on the engine and not just on the side of the car as a sponsor is indicative of how much technical support the brand has given our program. In the past, we've competed with engines that were based on Chevy parts but weren't necessarily a Chevrolet engine. The Chevy Racing engineering and marketing staffs have really embraced the TSR racing programs, and the debut of this new engine is the start of another exciting new chapter in our relationship."

Let's start with the good stuff. The new methanol-burning 166ci (2.7-liter) Chevy Midget engine produces more than 350 hp. That's more than two horsepower per cubic inch. The lightweight, inline four-cylinder engine starts with an aluminum block and cylinder head. The head has two valves per cylinder operated by pushrods and rocker arms, is equipped with mechanical fuel injection and utilizes an electronic ignition system.

At the maximum displacement of 166 cubic inches and in compliance of USAC rules, the Chevy engine runs methanol fuel. The inline four aluminum block has dry iron cylinder liners; the kind that are simply put in place and usually retained by the application of the head. This is opposed to a press fit where the sleeves are 'frozen' and temporarily shrunk in a freezing liquid such as nitrogen or CO2 and then squeezed into the block. 'Dry' sleeve technology allows the block to act much like a tool holder for all the engine's components. Also, a damaged sleeve can easily be repaired-quite possibly at the track.

The engine uses a gear-driven mechanical roller camshaft and shares its 6.5-inch crankshaft-to-camshaft dimension and 60mm camshaft core diameter with the championship-winning Chevrolet R07 NASCAR engine. A bigger diameter cam will provide more finite cam designs, allowing for tuning to track applications.

The Midget motor's belt-driven dry sump oil pump and high-pressure mechanical fuel pump are mounted on the right side of the engine. With these components located outside the block, they are more accessible for maintenance. Also, being on the 'cold' side of the block (the exhaust comes out on the left side) they are less susceptible to heat damage.

All the specs of the new engine fall in line with USAC rules which apply to a wide swath of engines including four and six cylinders, two-valve and four-valve cylinder heads, overhead valve, single overhead cam, and dual overhead cam valvetrain designs. The new Chevy Midget racing engine uses the same proven pushrod/two-valve layout that has been the standard of GM small-block V-8s since 1955, retaining the now-classic design's core of simplicity, reliability and light weight.