No oil to top end

I don't consider a sticking bypass valve a "failure" of the oil pump, simply because an oil pump should be completely disassembled and inspected and clearanced if desired, before installation. To me, that's just a normal part of a build. So a stuck relief valve would be caught and dealt with then. I do agree with Karl though that if an oil pump cannot handle the debris that's small enough to come through the pickup screen, then it's a POS. I always use Oil pumps that are made in USA. If you've ever seen an import knockoff, then you know there's a difference.