PRI asked a variety of fastener manufacturers about maintaining fasteners. Their answers varied, depending on the type of fastener.
Locking fasteners, according to Glenn Thompson of Stage 8 in San Rafael, California, should never require replacement. “The bolts that do need to be replaced are the head bolts, which are designed to stretch, but you can only stretch them so many times.”
Ken Sink of Milodon in Simi Valley, California, recommended regular replacement of any engine fastener that stretches. “Head bolts stretch every time you torque them down, and then when you have to replace a head gasket at the races, they snap. And every time you tear your engine down, you should replace all of your rod bots. At least replace them every season, because of the beating they take. And after x-amount of laps, replace the main studs, too, because they stretch. It helps to keep things fresh when you’re trying to keep the crank in the motor.”
According to Chris Raschke of ARP in Ventura, California, “All fasteners on a race car should be inspected regularly. When rebuilding an engine, look for rust or corrosion, and replace any fastener that shows any sign of it. If you don’t know the history or run time of a critical fastener, then it should be replaced. If a critical fastener such as a connecting rod bolt fails, it could be fatal for the engine, costing you the race.” Wheel studs deserve special scrutiny, he added. “They take a beating and transfer all the horsepower to the ground—and a loose wheel can cost an untimely pit stop or cause great bodily injury.”
Rivets, on the other hand, are designed to be permanent fasteners and should not require any routine maintenance. “Bolts are made to be removed,” said Butch Novak of Speedbear Fasteners, Imperial, Pennsylvania. “Rivets are not.”
That said, Peter A. DePauola of ADP Rivet in Hartford, Connecticut, lamented a widespread misunderstanding regarding the permanence of rivets. “It’s disturbing how weak, inferior and even defective rivets have lowered expectations. Rivets should not just ‘loosen up’. The nails should not break off high and need to be cut off. The heads should not pop off, and rivets shouldn’t fail on a regular basis. The only time a rivet should be replaced is when the parts it is holding together need to be replaced—which is often the case in auto racing, where body panels are frequently dented beyond repair.”
“If rivets are installed properly,” agreed Gene Virus of Racingrivets.com, a division of Great Plains Fastening Systems in Concordia, Missouri, “and that means drilling the right size hole, and using the right tool to set them correctly, then they should last until you need to remove them for access or to change body panels.”
The same is true for quick-release panel fasteners, according to Jon Lynch of Behrent’s Performance Warehouse, Florida, New York. “If installed properly, no panel fastener should ever “fail during a race in any application. We recommend referring to the deflection chart on our website to prevent this from happening.” That said, “Always replace any fastener that shows signs of wear or distortion from repeated removal and reinstallation. Most importantly, any fastener, spring, or plate damaged in a wreck should be replaced.”