From 17 hours to 1: how Hendrick Motorsports revolutionized cylinder block machining with GROB

At Hendrick Motorsports, it was recognized early on that the production of key engine components required a significant increase in precision. “

It quickly became clear that we needed to improve accuracy on some of our most critical parts. That’s when we started exploring different options and came across GROB,” recalls Scott Maxim, Vice President of Powertrain at Hendrick Motorsports.

“The differences between winning and losing are now measured by the thousandths of a second,” Maxim continued. “Which means precision and repeatability are crucial in staying ahead of our competition. And much like our advanced metrology partnership, GROB has given us an advantage in this area.” The decision fell on GROB universal machines—two G350a and one G550a—with resounding success.

Flexible machining with maximum accuracy

The production process starts with cast blanks supplied by General Motors. These undergo complex machining operations such as surfacing, drilling, threading, and grooving. The transition areas in the cylinder head, where gas exchange occurs around the valves, between the combustion chamber, intake and exhaust channels, are particularly challenging. “This is exactly where GROB technology shows its strengths. The machines are reliable and precise. Combined with the Siemens control system, machining is now more transparent and easier to manage,” explains Jay Grubbs, CNC programmer at Hendrick Motorsports.

Workpiece machining with maximum tool length

A key advantage lies in tool handling: collisions with fixtures are now a thing of the past. “Thanks to the tunnel concept, the tool completely moves out of the workspace. The workpiece can be freely moved—without risk,” says Michael Tummond, Engine Engineering Manager at Hendrick Motorsports. The special axis concept of the GROB universal machines allows the full tool length to be used in every axis position, even with the largest workpieces—a benefit for Hendrick Motorsports. “The true 5-axis machining with GROB is unexpectedly straightforward,” says Grubbs.

Massive time savings and higher quality

A highlight is the dramatic reduction in machining times for cylinder blocks. Previously, the complete production process from raw casting to finished part took 15 to 17 hours and required multiple setups. With GROB technology, all of this is now completed with a single setup in less than an hour. “We achieve time savings—and with even higher precision,” summarizes Michael Tummond.

The first two series of race cylinder heads have already been produced—with outstanding accuracy and repeatability. “It is impressive to watch the G550a machining an engine block. It moves the workpiece with incredible ease, at high speed, and with the utmost precision,” says Maxim.

Stable processes through close collaboration

In addition to the machine technology, collaboration with GROB engineers was critical. “Developing the fixtures together allowed us to achieve stable and consistent setups. The improved clamping was key to taking the quality and precision of our parts to a new level,” recalls Maxim.

With the investment in GROB universal machines, Hendrick Motorsports has taken a significant step forward: more precision, shorter machining times, and outstanding reliability. “The care we put into our work is directly reflected in the performance of the machines. That’s exactly why investing in GROB for the critical components that directly impact on-track performance was the right decision for us,” concludes Scott Maxim.