It’s absolutely no secret that we are HUGE fans of the Science Channel’s TV show, “How It’s Made.” So when you take that premise, add in our favorite nuclear-physicist-turned-camshaft-guru Billy Godbold, and have it recorded by the YouTuber Stapelton42 (who is fast becoming one of our favorites), you get a video that we are guaranteed to love.
As part of Lake Speed’s project to get his dad’s 358 cubic-inch NASCAR engine (which we covered here) back into fighting shape, COMP Cams has agreed to whip up a bumpstick for the combination that will make great power. Since Mitchell has been documenting that whole process, it only makes sense that COMP opened up their shop for a super in-depth look at both the history and current process of making camshafts.
Behind The Scenes Of Camshaft Manufacturing
Starting off with a quick overview of camshaft design, Godbold starts by saying, “People think that camshaft designers design the lobes. They don’t. They design the valve motion. Then you track it back through the components and figure out how it is you need the lifter to move to achieve that valve motion. That creates the profile that you have to grind on a bar of steel.”
“Sort of like Michelangelo carving David out of marble – he looked at the marble and cut away everything that wasn’t David. That’s how we make a cam,” Godbold explains. “We don’t add any material. We start with a bar of steel and cut away everything that isn’t a camshaft.” Godbold then proceeds to walk the camera through the process from bar stock, to a “spool” — which is a camshaft with the journals cut but completely round lobes — to cutting rough lobes to make it a camshaft blank.
Then, in a rare in-depth look, Godbold walks through the incredibly interesting process of grinding cams on the Berco manual camshaft grinding machine. Then, as a contrast, we get to see the modern CNC automatic cam grinding machine, and the fact that it can make a camshaft in about 15 minutes, compared to the “eight or nine a day” that they could expect from a master craftsman on the manual machine.
From there, Godbold takes you on an inside tour of the quality control room of COMP Cams. “This room came about because of something Scooter Brothers told me once,” shares Godbold. “You’re trying to make ball bearings and measure them with wooden calipers. You can only make something as good as you can measure it.” The result of that conversation is why COMP’s QC department has Adcole machines that can measure camshafts to beyond the trillionth of a degree on duration and then about 10-12 millionths of an inch of lift.
That kind of precision might seem like overkill for simple profile checking, but when checking for the wear on a camshaft during testing or after a race, that precision makes all the difference. In addition to raw measurements, surface finish measuring is a big part of the COMP QC department. That leads to a discussion of COMP’s superfinishing processing.
The video wraps up in Godbold’s favorite place in the building, the test cells — specifically one of the Spintron cells where COMP measures and validates the exact valve motion created by its various products. If you have any interest in the process of camshaft design and production, we strongly recommend you watch the above video in its entirety, as it’s absolutely worth the time investment.