Chevrolet Corvette Powertrain: Performance Starting on the Plant Floor


Chevrolet Corvette Powertrain: Performance Starting on the Plant Floor

Editor’s Note: We are honored to share an article submitted to from Eric Nordling, Product Engineer at the GM Tonawanda Engine Plant and Bob Widmer, Production Launch Operations Manager, GM’s Toledo Transmission plant. Eric and Bob shares with us some of the high-tech machinery that helps to build the Corvette Stingray’s LT1 V8 engine in Tonawanda, NY and the eight-speed automatic transmission manufactured in Toledo, OH.

Since the original Small Block V8 engine was introduced in 1955, the Chevrolet Corvette has been famous for uncompromising power under its hood. But while Corvette drivers can see and appreciate the technology and innovation under their hoods, what very few people get to see is the advanced infrastructure and devotion to quality at all costs that goes into building the Corvette’s powertrain. Through seven generations of America’s most iconic sports car, General Motors engineers and workers have continually refined the state of the art in the manufacturing and assembly plants that build and test the Corvette’s engine and transmission, constantly finding new ways to make the Corvette more powerful, reliable and efficient.

The 2014 Corvette Stingray was named the 2014 North American Car of the Year at the North American International Auto Show, Road & Track Magazine’s “Performance Car of the Year” and WardsAuto selected the Corvette’s Gen 5 LT1 Small Block engine for its “10 Best” list, thanks to the 6.2L V8 producing 460 horsepower while delivering an EPAestimated 29 MPG highway.

Reviewers and awards committees all applauded the Corvette powertrain’s advanced technology that includes Direct Injection, Continuously Variable Valve Timing and Active Fuel Management (cylinder deactivation) and 8 speed automatic transmission. In GM plants in Tonawanda, NY and Toledo, Ohio, workers use space-age technology to manufacture, assemble, test and verify engine and transmission components to tolerances that were unthinkable even a few years ago. The workers who build these engines and transmissions are surrounded and supported by automated test benches, negative-pressure assembly rooms, laser measuring systems, gas spectrometers, automated high-pressure wash systems, robotic vacuums and much, much more.

Turn any corner on the plant floors of Toledo or Tonawanda and you’re virtually guaranteed to find a high-tech tool dedicated to performance and quality:

  • Chevrolet Corvette Powertrain: Performance Starting on the Plant FloorEven microscopic particles in the hydraulics of a transmission can cause a delay in shifting or even failure over time. That’s why the valve body in the Corvette’s 8-speed automatic transmission goes through such comprehensive cleaning and quality checks before it’s sealed. It’s first power-washed at 5,000 PSI with water filtered to below 10 microns of cleanliness then delivered to a positive-pressure room. There, it’s gauged to ensure that it meets tolerances within a few microns, has more than 100 ultra-high resolution photos taken robotically and automatically compared to a perfect sample and is scanned with lasers to further ensure its quality. It’s then powerwashed again with filtered and demineralized water that uses a special detergent to eliminate deposits and finally delivered to the cleanest room in the plant, where it’s blasted with air filtered to within 10 microns to remove any potential remaining sediments and scoured with a robotic high-pressure vacuum. Only then is it finally sealed.

  • Planetary gears in transmissions are hard-finished to micron levels of smoothness to the point where they look like steel mirrors, fine-tuning the shape and fit of gear teeth to deliver the smoothest, most precise fit that reduces transmission noise and improves long-term durability.

  • The arms of the Smart Cell robots that put together rotating clutch assemblies in Toledo precisely measure installation force on each clutch component as they install them. This provides a final check that each part assembled properly and meets the designed tolerances to ensure smooth, reliable and precise shifts up and down through the Corvette’s eight gears.

    Chevrolet Corvette Powertrain: Performance Starting on the Plant Floor

  • Each engine block and cylinder head carries with it a record of all of its manufacturing and assembly history and test results in a “data bolt” that is read and written to by each assembly procedure and test station. The reusable bolts are the equivalent of an engine’s individual school transcript, recording its entire trip through the plant and ensuring that it’s passed all its requirements before graduation. Any missing operation or out-of-bounds test result automatically removes the engine from the line for workers to review and address issues.

  • The LT1 engine’s fuel injection system operates at the same pressure as an industrial power washer. To test its integrity, the system is pressurized with helium and surrounded by a vacuum while a mass spectrometer sensitive to more than one part in a billion watches for individual molecules of escaping helium, detecting leaks one hundredth the width of a human hair.

  • A dozen automatic Coordinate Measuring Machines (CMMs) probe cylinder heads and engine blocks, measuring more than 11,000 data points to less than three microns. A half-dozen even more precise CMMs test surface finish to less than a micron, watching for surface irregularities that could lead to engine leaks and decrease long-term performance.

  • GM’s required manufacturing tolerances are so precise that suppliers of testing and measurement equipment have had to upgrade their standard tools and procedures to meet the Corvette powertrain’s requirements. While many testing tools require a stable temperature to operate to the manufacturer’s requirements, GM’s Toledo quality team rewrote one supplier’s specifications to require an even more stringent temperature control in order to ensure GM’s quality targets. Another supplier that had planned a yearly recertification of its measurement system is required to quarterly certify the precision of their system’s operation.

    Chevrolet Corvette Powertrain: Performance Starting on the Plant Floor

The end result of all of this measuring, testing, cleaning, washing, drying, sensing, and testing and measuring again and again is felt every time a Corvette hits the road. Every micron of tolerance improved, every microscopic imperfection removed, results in performance, efficiency, reliability and durability – and in the end, they add up into one of the world’s finest powertrains under the hood of one of the world’s most iconic sports cars.

This guest post was written by Eric Nordling, Product Engineer at the GM Tonawanda Engine Plant and Bob Widmer, Production Launch Operations Manager, GM Toledo Transmission plant.


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