I had a leaky manifold gasket on my 8n. When I took the manifold off to replace the gasket I noticed that the manifold was worn away where it was leaking by cylinder 4. Fortunately the block wasn't damaged so I got a new used manifold, and new gaskets. I put it back together and the leak is fixed, but there is still a ticking that I hear from around cylinder 4. Is it possible that I waited too long to fix this and the leak has created valve or other engine damage?