A schneider cam for a start is made up of a compound of largely sinterd iron not steel as the genuine items are hardened an solid, here is the scenario, I do not use those cams they are soft not treated, wear out have impurities in the castings, which block oil galleries, they twist wear, and break and are not of the grinds specified on the sheets of cam timing specs they produce to be, people may disput this but proof is many poodings that have failed , Nytriding these cams is even worse as it weekens them further, As typical of all nissan engine components they are of good steel forgings