My engine has made this "knocking" sound ever since I bought it. I rebuilt it 2 yrs ago & really did not find anything in the reciprocating assembly that would cause it.I had the injector pump&injectors tested at the time of the rebuild @ D&W diesel they said every thing was ok."knock" was still there. Afriend of mine told me to feel the injector lines so I did & boy do I feel noticeable "pulse" on #5, so what does this mean? any ideas? thanx John