While Jesel has built its brand of valvetrain innovation with shaft rocker systems there are some race sanctioning bodies that still prohibit shaft rocker conversions such as NHRA and IHRA Stock Eliminator classes. Despite their extreme sophistication in many respects, these “stockers” are still required to run stud rockers.
Back in the early ‘90s, Jesel designed high-tech stud rockers for NASCAR racers that faced similar rules restrictions at the time. Jesel has reintroduced its innovative design with several new features made possible with improvements in materials and machining operations. However, true to their unique design, they require no bothersome stud girdles or guideplates—instead, the rocker pivots on a steel stanchion post that engages Jesel’s patented retainer plate to keep the rocker arm perfectly aligned with the valve. It is securely fastened to the cylinder head using a 7/16-inch to 3/8-inch stepped stud and ARP 12-point nuts. The steel stanchion post can be shimmed up or down to adjust the rocker arm height for correct valve tip geometry.
Jesel’s main areas of focus for improving on its 30-year-old design was to remove weight to reduce the moment of inertia and to reduce friction with premium dual 3/8-inch-wide bearings with external thrust washers that ride on precision-ground, tool steel trunions. Needle bearing nose rollers further reduced valvetrain friction. The precision ultra-lite CNC bodies are machined from 2024 aluminum, then receive a shot-peened finish to help resist fatigue from stress under hot operating conditions. Jesel’s proven 3/8-24 cup style adjuster allows for precise valve lash setting.
Currently, Jesel’s Premium Stud Rockers are available for 24-degree Big-Block Chevy heads, but other popular engine models will be made available. Engine builders have reported significant horsepower gains as well as increased valvetrain stability at extreme rpm. For more information go to www.Jesel.com.