On Thursday, April 27, 2023, twenty-three people from various local car clubs participated in the Valve Cover Racing ("VCR") Clinic at Lee Jacobsen's garage. A few finished VCR cars showed up but the majority of the participations were there to set up their VCR car.
For those just starting the process the first step was to pick a wooden platform with metal brackets (for axles) attached. Lee had quite a few on hand. Then pick a set of wheels and axles. Then mount the wheels and axles to complete the chassis. Then one may add some foam rubber to the chassis to form a front bumper. This helps reduce the impact to the car when it collides with the barrier at the end of the track. The next step is to test the completed chassis before mounting your valve cover. This step is crucial as the VCR must run straight down the track. If it ventures across the center line, it is disqualified. If it moves off the side of the track further than the soft bumper at the end, it is disqualified.
Once the wheels and axles are aligned and the chassis tracks straight, you mount your valve cover to the chassis. This is initially done with a plastic "velcro-like" band that is wrapped under the chassis and then over the valve cover. Typically the band is used in two places to hold the valve cover firmly on the chassis. You can, of course, make, that mounting more permanent if you desire later. You then test your car again to see that it still tracks well after mounting the valve cover. Once it tracks well you turn your attention to establishing the car weight.
There are different weight classes, so you pick one and then add weight to your VCR until you are near, but not over, the maximum weight for your class. Adding weight is somewhat of a controversial topic. Should you add the weight to the front, back, or middle of the chassis? The weight is to help the car overcome the friction of the wheels on the track and allow the car to increase its speed down the track quicker. Some think the weight in front is better, some think the weight in the rear is better. I did not see any intricate calculations being made, but one can imagine that competition could take it there for some folks.
Speaking of wheels, that is another area that seems to draw a lot of attention for those who wish to shave bits of a second off their car's travel time down the race track. The maximum diameter permitted is six inches, and some wheels are wider than others. And some smaller and narrower. The issue appears to be to decrease the contact area of the wheel to the track thus minimizing friction. Truing up the circumference of the wheel (roundness) and reducing the width of the wheel where it meets the track become the areas for tweaking your VCR. And of course, reducing the friction between the wheels and the axles is another area of possible improvement.
Some VCR cars are simple and plain. Some are quite well-finished, and some are "unique" (think water pipes sticking up from the valve cover to add weight - and I think are just begging for sails).
And no trip to Lee's garage goes without a little looking around to see what is new, or what progress has been made on the plethora of cars there.
Phil Crutchfield
