SPRINGS HOPE ETERNAL

What is the most overlooked factor—other than restrictive rules—holding modern racing engines back, preventing them from reaching their full potential? If you answered “cylinder heads,” “rotating assembly,” or even “camshafts,” well, that’s no longer the case. Believe it or not, it’s the valvespring!

By the mid-1990s, bottom ends were reasonably reliable and the tech was available for further durability improvements in response to increased power potential, which was no longer restrained by cylinder-head flow bottlenecks or cam lobe profile design limitations. Cutting-edge race engineers realized significant top-end power gains were possible by extending engine operating ranges if the one key remaining bottleneck could be overcome: valvespring longevity and stability. NASCAR teams led the way in revolutionizing valvespring tech, in some cases even sponsoring start-up niche valvespring companies that developed new valvespring tech to reliably increase pushrod engine speeds to 12,000 rpm and beyond in extended closed-course racing, where springs must survive millions of cycles without failure.

But as the spring wars heated up, staying competitive led to higher and higher rpm, and ever more costly engines. Smaller teams were finding it increasingly hard to stay competitive. Around 2008, NASCAR finally put a lid on it, instituting a “gear rule” that effectively limited engine speeds to “only” 9,200 to 9,500 max rpm. In 2015, this was followed by a rule mandating that only 13 engines can be used (or used up) during the entire race season (37 races for 2019!). The upside: reliable NASCAR engines that last multiple races with few catastrophic failures. Meanwhile, the technological improvements that led to, and resulted from, the spring race have trickled down into other types of racing, even to today’s cutting-edge performance OE street cars and our real-world hot rods.

Working with Comp Cams Billy Godbold, over the next several months, HOT ROD is going to take a