Kiggly Drag Beehive Valve springs 4G63
Kiggly Racing LLC Race Only Beehive Valve Spring Set for high rpm and high boost 4G63 applications requiring extremely high seat pressure. This kit is made in the USA and includes an aggressive PAC Racing beehive spring, FEA-optimized proprietary hardened chrome moly retainers and treated steel seats. This is a drop-in fit with all standard 4g63 components including keepers and seals. These springs are for serious builds only with a no-shim seat pressure of 131lb and can be shimmed 0.060" to 150lb at 0.470" /12mm lift. This high seat pressure keeps the valves from popping off the seat due to pressure waves up to ~62psi in most applications. By adding 0.060" shims(available through our store) extends allowable boost in most applications to ~73psi. Minimum seat pressure is usually determined by boost and not max rpm. Keep in mind that exact seat pressure requirements vary with manifold runner diameter and length as well as valve size, cams, and cam timing. Recommended for sanctioned drag racing only due to the high seat pressure and ensuing valvetrain stress and wear. Not for Use in Street Cars.