Went to put on my head the other day, crank pulley rotated fine. Went to align the oil pump sprocket timing mark and it was VERY hard to turn. It wouldn't turn by hand but if I used a wrench it would turn,stiff but it would turn. I will take the oil pan off, but what is the worst case scenario that can happen here. Car was running with no knock and just shut off after about 30 seconds. I bent two valves before and was wondering, could the stiff sprocket have been the culprit for me bending the valves in the first place? Could a faulty oil pump cause knock? What could be causing the pump to be so stiff? Any help is greatly appreciated.

 

Anybody?

 

The only times I've seen a pump that bad it has been on engine with wiped out rod bearing #1. Whether the pump seized causing the lack of oil or the bearing failed and debris jammed up the pump, I don't know which came first since they are brought to me immobile. I've had 3 tow ins like that though, and all of them were brought in for rod knock and the oil pump was like that (impossible to turn by hand, needing a pair of channel locks to move it etc) when disassembled for inspection.