When I broke in the motor the zinc was being reduced and knew nothing about it,if its a bad lobe I would think it would have shown up sooner as the motor has made 3 trips to Florida and runs great except for what sounds like one lifter making noise which is getting slightly worse. The builder of the motor installed the wrong cam and would like to replace it but since he had a questionable reputation I am afraid I am going to open a can of worms since it does blow some oil out the breather.