my 92 240 s13 had a sound coming from under the valve cover so i opened it up and realized that one of the timing guide was broken im guessing made that was what the sound was and that made the piece is in there but i couldn't find it so i just drove it a little more then realized it started to get worse so i try focusing trying to find where it might be then i started to realize that the sound moved down now it sounds its in the head but im 99.9% its not the rods cuz it sounds like a knocking sound so i dont kno what to do now my car just sit at home if anyone has an idea on how i can save the motor or just wait till i get enough for a new one lmk!!!!!!!!!!!