Ruby Fan
Well-known member
I have been seeing articles popping up about the reducing of zinc in conventional motor oils to prolong the life of the cat. converter. The problem here is that if there is not enough zinc in the motor oil, with engines that have flat tappets, the oil would not 'turn' the tappet to create an even wear, which ultimately results in camshaft failure. The engines that are designed to use SYN, have roller rockers, etc, so there is not a problem with them. What oil is best for '90 and under Vettes? I'm pretty sure that 10W-40 has more zinc, but has not been recommended in ages. This problem could also cover '75 on up engines. So maybe SYN is not good for all engines. What do you think/recommend??
