Engine vavle for BESFORD Forged parts CNC minimum tolerance: +/-0.01m Forge minimum tolerance: + 1.material: material for inlet valve: SUH-3 (4Cr10mo), SUH-1 (4Cr9siz),magnetic material for exhaust valve : SUH-35(21-4N) , SUH-38(23-8N), SUH-3+SUH35, non magnetic2.The using life of our engine valve is over 80,000 kms in two years. good quality SUH-3 magnetic KOMATSU S6D125 engine vavle