Racing Tech Inspection Tools

by Richard Rowe

Tech inspections serve two basic purposes. Safety is the first and most important; tech inspectors will sometimes let racers slide on certain class-restriction rules, but safety rules are rarely so flexible. Class-restriction rules such as those for engine displacement and tire size help to maintain parity among cars competing within a given class.

NHRA Tech Book

While it may not seem like a "tool" per se, the tech book is the alpha and omega of a tech inspector's daily routine. Most drag strips have standardized on the National Hot Rod Association's safety and class limitations, but some use the International Hot Rod Association (IHRA) rule book for certain events. True to its name, the IHRA standards typically apply to events held in other countries such as Canada and the U.K., and to race series that span the world, such as the Summit Racing Equipment Super Series. Road race courses and autocross events typically use the Sports Car Club of America (SCCA) rule book and class structure, and stock car events usually go by NASCAR specs.

Basic Measuring Tools

Aside from the rule book, the tape measure is a tech inspector's best friend. Tape measures and metal rulers are useful for any number of measuring tasks, from tire size to roll bar clearance to spoiler size. Dial calipers are equally precious for measuring engine clearances, wire gauges, wheel stud protrusion and other things that require more precision than a ruler can offer.

Advanced and Specialized Tools

Some tech inspectors like to use drafting rulers with one or a pair of sliding bars, which essentially turns the ruler into a giant dial caliper minus the dial. Tech inspectors who regulate Formula or spec-car classes such as Formula 1 or NASCAR Nextel Cup may have dozens of wooden, metal or plastic templates that fit over the car body or chassis components to ensure instantly that the component conforms to the proper spec.

Bore Measuring Tools

Engine displacement is a major factor in many racing classes, but can be a bit difficult to measure. As such, tech inspectors usually only check it on suspicion of cheating. Bore-measuring tools are long rods that the inspector slides through the spark plug hole. After it goes into the bore, a pair of spring-loaded arms open, stop against the walls and give the inspector a bore measurement. Stroke is a bit more difficult to measure on engines that don't use a centrally-mounted spark plug. For tracks that don't have a specialized stroke-checker, tech inspectors will often insert a length of wire into the cylinder through the plug hole so that its bottom rests on the piston. The inspector will then turn the engine over by hand and mark the wire with a marker at its highest and lowest points. The distance between the two marks will give the inspector some indication of the stroke. It's not an exact method since the method measures the bore's diagonal distance instead of its vertical distance. However, it's close enough that the inspector may warrant an oil pan removal for closer inspection.

About the Author

Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.

Photo Credits

  • photo_camera green sportscar image by Christopher Dodge from