A-31744133-AI Spring, Valve InnerOne New Aftermarket Replacement Valve Spring (Inner) for Perkins Engines Fits Massey Ferguson, White, and More This inner valve spring is a direct aftermarket replacement for Perkins engines used in Fits Massey Ferguson tractors, combines, backhoe loaders, and other equipment. The inner spring works in conjunction with the outer valve spring to maintain proper valve closure and timing in the engine's valve train. Sold individually. Specifications