My buddy adjusted his valves and now it rattles like its loose. I checked them and they are on the loose side forsure, but within specs. Is there a way that you can mess it up adjusting the valves. I asked him how he set them and he said he spun the crank till he got tdc etc, but he did mention he passed up the mark and then he rolled the crank back a bit. Could this have messed up the rod bearings? I told him it could have but i am not forsure. Thanks.