Jim H - Thank you for your advice - I tried each cyllinder, in fact I disconnected the fuel line completely at each cylinder. The knocking noise did not change on any of them. Is there another typical issue with the 617 diesels that I should look at? It is loud enough that I do not want to drive it anywhere. Thanks

Also the skinnerbox site has multiple dead links, I can navigate to the point where it would pull up a pdf file and it can not find the page??? All of the menus work, but then they dead end.