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Bigger Is Not Always Better

Bigger is Not Always Better

Many people do not understand that a bigger stud diameter is not always better for a given application. For a head stud to function properly and not loosen while in operation, it needs to be tightened so it has a specific amount of tension. If it has too little tension it will loosen from vibration. If it has too much tension it can bend or distort the cylinder head or engine block/case resulting in expensive engine damage. A properly designed head or main bearing stud must also allow for the thermal expansion that all engines experience when going from ice cold to searing hot. Many people falsely believe that going to a larger diameter head stud is the solution to preventing head gasket leaks. This is often untrue and can actually result in broken cylinder heads, damaged cylinders on air-cooled engines and damaged engine blocks or cases.

To meet all of the above operating requirements a head or main stud must be properly designed, engineered and manufactured. While there are basic engineering parameters incorporated in all stud designs, the best head or main stud design is part science and part “art.” You can’t just open an engineering book and find a formula that tells you the best design for a given application. When increasing the stud diameter, you must increase the tightening tension on the stud to keep it from vibrating loose. This increased tension and clamp force can bend or distort the block and head, causing cracking and leaks. The larger diameter stud may also not allow for proper thermal expansion, resulting in stripped threads in the block.

There is a fine line between the proper clamp force to prevent leaks and bearing shuffle and too much clamp force that can cause engine damage. This is where experience matters. Unlike other companies, RACEWARE™ delivers ultra-high strength Aerospace Quality engine fasteners that are a perfect fit for your engine. In addition RACEWARE™ fasteners are easy to install. No machine work is required to install genuine RACEWARE™ head or main bearing stud kits. They are a direct replacement for the original studs or bolts.

It’s also important to understand that one tightening torque figure does not fit all fasteners of the same diameter because the structural rigidity of the components being used varies, and thus the clamp force and tightening torque must also change to match the application. We’ve seen some fastener companies specify TWICE the proper tightening torque for a head nut on Porsche engines, resulting in expensive engine damage after the engine has been run up to operating temp a few times. More proof that a higher nut tightening torque and excessive clamp force are not the correct choice. With RACEWARE™‘s 40+ years of engine design expertise you get the absolute best engine fasteners and detailed installation instructions for your engine.

Designing and engineering the best threaded fasteners for the application requires vast expertise in engine design. For over 23 years RACEWARE™ has been delivering the ultimate threaded fasteners for the German engines. The more you know about engine design, the more you’ll want RACEWARE™ in your engine.

A sincere “Thank You” to Professor Ferdinand Porsche for the wonderful automobiles he delivered to the world!