This 3174A025 valve spring is designed for 4-, 6- and 8-cylinder Perkins 1004/1104/1106 diesel engines (4.4-8.8 L) used in various industrial applications including JCB 3CX/4CX back-hoe loaders, MF 5400/6400 tractors, 45-250 kVA generator sets, Claas combine harvesters, and marine auxiliaries. It effectively controls inlet and exhaust valve motion at speeds up to 3,000 min⁻¹ while meeting EU Stage IIIA / EPA Tier 4-final emission limits.

Manufactured from chrome-vanadium spring steel (50CrV4) oil-quenched and tempered to 47 HRC, then shot-peened to 0.25 mm A-intensity to achieve fatigue life of 1 × 10⁷ cycles. The 50CrV4 alloy (0.5% C, 1% Cr, 0.15% V) provides 1,600 MPa tensile strength and 8% elongation, resisting surge-set when exhaust temperature reaches 700°C. Controlled shot-peening induces 400 MPa compressive stress on the outer surface, delaying fatigue crack initiation and extending service life to 12,000 hours.

Surface is phosphate-coated 3 µm for 96-hour salt-spray protection and lightly oiled for corrosion-free storage.