I'm working on this v6 Evinrude block, and had one cylinder bored out (.030) and the other's honed. I'm working on trying to break the edges, to keep the rings from catching. I can use my dremel tool to get at the upper lip, but I'm finding it hard to get at the lower lip of the port. How is this done? is there a special type of file that is used?<br /><br />Mik