Looking for anyone who can help me understand what caused the fuel pump eccentric to score the inside of the timing gear cover in a circle about an inch wide. I was in the process of replacing the water pump when the top bolt broke clean. A lot of time trying to extract it led me to pull the timing gear cover when I discovered the scoring. Fuel pump eccentric seems to be tight, less than a quarter inch play on the timing chain, and no apparent play in the timing gear. Thanks in advance for the information.