The amount of research and development that continues to go into improving the pushrod-activated, overhead-valve internal combustion engine never ceases to amaze us. This hoary, old, but tried-and-true basic architecture has been around for...
What? A hundred years, give or take a few? No matter-for most of you reading this, the more important figure would be that Chevrolet's classic version of this powerplant has been around for just over 50 years. Its demise has been frequently predicted, and yet here we are with better classic small-block Chevy motors than ever. Aftermarket blocks, premium forged internals, heads that flow like race lungs from a decade ago, and that's just scratching the surface. The quest for power with this classic platform shows no signs of slowing down.
And if that's not enough, we got a new and improved pushrod small-block in 1997, the LS1 and its descendants. The advent of this newer platform leads the quest for power along a whole new and rapidly evolving avenue. But if there's one thing the two have in common-besides the obvious basics-it's that both GM small-blocks have driven a boom in camshaft design and technology. It makes sense-a bulletproof bottom end, great-flowing heads, and the right intake are all useless without a properly matched camshaft.
Over the past couple years we've taken a couple opportunities to dive headfirst and deep into the world of camshafts, seeking to explore and explain every facet of camshaft theory we could possibly think of. If that's the kind of article you're looking for-and we encourage you to check them out-you can find both of them in your back issues. "Performance Profiling" was in May '07, and "Got Lobes?" was in Mar. '08. They're also on our website, www.chevyhiperformance.com. We don't claim that they'll tell you everything you need to know about camshafts, but we will say they come pretty darn close.
For this article, we've decided to take a slightly different track. Rather than rehashing the hows and whys and dos and don'ts of choosing a camshaft, we decided to get on the horn to some of the top camshaft designers and engineers in the business and simply ask them to tell us about their latest and greatest. The cool thing is that's exactly what they did, letting in on some of their newest innovations.
Although it probably shouldn't have surprised us, we were slightly taken aback to find out that each company seemed to be working on different aspects of the whole cam-design picture. Somehow, we thought everyone would be barking up the same tree, that tree being camshaft design for the LSx family of engines, and we were partially right. Creating bumpsticks for the Gen III and IV engines is definitely a growth industry. But even within this modern small-block family, the approaches being taken to craft power-producing camshafts run a wide range. And that's just for naturally aspirated LSx's. According to our experts, the big rumble within the boom in LS cams comes in the forced-induction area-nitrous, superchargers, and especially turbochargers, we're told. More and more enthusiasts are putting the squeeze on their new-school powerplants. Like we said, however, that's just one lane on the road, and other companies are putting their own twists on LSx camshaft design.
Does all this interest in creating cams for Gen III and IV powerplants mean that new go-fast 'sticks for traditional small-blocks are taking a back seat? We'd have to say the answer is "maybe." We only discovered a few lines of newly designed, traditional small-block cams. What we did discover, on the other hand, is more than a handful of new valvetrain pieces developed to take better advantage of the modern cam profile designs created over the past decade or so. As we've learned on several occasions, and as the cam designers know way better than we do, an aggressive cam is of only limited benefit if the rest of the overhead valve system isn't keeping the valve in control. So springs, rocker arms, lifters, and even premium pushrods continue to be developed for traditional engines.
A primary goal of cam design, whether we're talking about traditional powerplants or the modern LS versions, is to get the valve open as quickly as possible at the precisely right time, hold it open as prescribed, then close it-and all this in perfect control. This, we found, doesn't seem to change as cam design progresses. It pretty much fits into the ethos of all cam designers.
But as for the details, that's where all the difference is made. With those particulars in mind, we'll take a manufacturer by manufacturer look at what each is up to and at the kind of cam technology you can expect in the future.
What We DidInterrogated some of today's best camshaft-designing minds to find out just where the cutting edge lies.
Bottom LineCamshaft design is one the most fertile areas in the field of internal combustion.
CostFrom hundreds to thousands, depending on what you're trying to accomplish.