Volume II, Issue 5, Page 7

One might not know it from the win column and which brand won last year’s Nextel Cup, but Chevrolet has been racing in NASCAR’s top stock car series with a small-block V8 having design disadvantages compared to its competitors. Dodge and Ford have had enhanced cylinder block and head designs for the past few years, and Toyota arrived in 2007 with an engine package incorporating these advantages from the start of their NASCAR Cup racing.

After lobbying NASCAR for at least two years, and in-house testing/design for more than that, Chevy was authorized to start using a new engine package in 2007 – the RO7. At this writing, not all of the Chevy teams have made a complete swap with their tried and true SB2 V8s to the R07. Prudently, they have been filtering them into races as they replace their SB2 inventory.

According to Chevy, the R07 is the first purpose-built engine designed and developed by GM Racing specifically for Cup. It is not such a close variant of production-based engines as previous Cup engines were. We’re going to review its design genesis and technical features.
Mark Kent, Director GM Racing, with Jim Covey, GM Program Manager for NASCAR Engines introducing the Chevy R07 engine at Texas Motor Speedway earlier this year. (GM Racing/Dorsey Patrick)

Words by Glen Grissom
Images by GM Racing
05/15/07

Chevrolet’s new NASCAR Cup engine: the R07. An obvious difference from the previous stalwart SB2 is the ignition distributor at the front of the engine. Who would have thought they’d see a Chevy engine with that?

New Design “Box”

The R07 replaces the SB2 (Small-Block / 2nd generation) engine that has been used by GM Cup teams since 1998 – an eternity in racing. Teams and GM started working on a successor to the SB2 in 1999, and multiple variations of a conventional small-block V-8 were designed, tested, and evaluated. There were R03 and R05 versions along the way that didn’t make the cut.

NASCAR and its participating manufacturers discussed in 2004 a potential "Engine of the Future." The thought was that it would come into the series alongside the Car of Tomorrow body/chassis that the Cup teams are starting to use now. The Engine of the Future was shelved, but the framework for future NASCAR engines started to take place.

Jim Covey, NASCAR engine program manager for GM Racing explains, "The discussions with NASCAR and the other manufacturers about the Engine of the Future were extremely productive. Although the Engine of the Future program was put on the shelf in 2005, NASCAR Nextel Cup Series director John Darby developed a list of parameters that defined the envelope for all manufacturers, thus giving Chevrolet an opportunity to develop the R07 engine. This 'box' set the boundaries for specific design features and minimum and maximum dimensions for key engine components.

"We had started to lay the foundation for a future Chevrolet engine, and we were able to adapt that design to the Chevrolet R07," Covey notes. "A prototype R07 engine was running durability tests on a dyno six months after we kicked off the program. The R07 engine development team included Ed Keating and Ron Sperry, who focused on cylinder heads and intake manifolds, and Ondrej Tomek, who was responsible for the cylinder block. We also worked with our key Chevrolet teams, GM Powertrain, and our suppliers.

Key Partners

"NASCAR's box provides considerable latitude for manufacturers to design their engines, and there are many parameters that have to be balanced," explains Pat Suhy, GM Racing Group Manager, Oval Track. "If a manufacturer maximizes one aspect of the engine design then it may limit what can be done in another area.

"Chevy NASCAR teams were deeply involved in the design of the Chevrolet R07," continues Suhy. "We meet monthly with representatives from our four key partners - Hendrick Motorsports, Richard Childress Racing, Joe Gibbs Racing and Dale Earnhardt, Inc. - to get their input on how we can make Chevrolet racing engines more reliable and easier to build and service. Many of their ideas were incorporated in the R07's final design, such as the integration of the oil and cooling systems.

"It's not about helping our affiliated teams to build the most powerful engine because each of them has developed their own proprietary parts and processes," he noted. "GM Racing's role is to provide premium quality, easy-to-use components. We want Chevy teams to be able to devote more of their energy and resources to winning races and less energy to preparing engines."