.039in Spring For Bypass

The 0.039in Spring For Bypass (Kinsler MPN 3339) is a precision bypass valve spring engineered for high-performance fuel system regulation in modified and racing engines. This component is essential for builders and mechanics working with advanced fuel injection systems, particularly those running adjustable fuel pressure regulators or custom bypass valve assemblies. Whether you're tuning a street performance build or developing a competition engine, this bypass spring maintains critical pressure stability across varying load conditions.

Manufactured from high-grade steel, the 0.039in Spring For Bypass features a precisely calculated wire diameter that determines spring rate and deflection characteristics under fuel system pressure. The compact dimensions (1.5 x 0.85 x 3 inches) allow integration into tight bypass valve housings, while the steel construction ensures durability across thermal cycles and pressure fluctuations. Spring rate and preload work in concert to establish the threshold at which excess fuel returns to the tank, preventing over-pressurization and maintaining consistent delivery to fuel injectors across the entire RPM band.

This bypass spring is ideal for engine builders customizing fuel pressure regulators, tuners fine-tuning fuel system response, and mechanics servicing Kinsler fuel system components. Proper spring selection directly impacts fuel pressure stability, injector spray pattern consistency, and overall engine driveability. Installation requires careful attention to spring preload specifications and valve body clearances—consult your fuel system documentation to ensure correct seating and load configuration before assembly.