Help!! Got my 77 MGB last year. It ran great till last month it all of a sudden started a loud knocking. Sounds like its coming from the engine block. I'm pretty handy with a wrench and I've worked on engines before (just not MGB engines) so I'm sure I could do most of the work myself. Just wanted to know if anyone has any idea if there is something I should check before I go and pull the engine...???