Had 7 passes on the new motor and on the drive back to the pits oil pressure falls to 30 lbs and the motor starts knocking. Pulled the pan & #2 main is down to copper, #3 rod is worn with no crush. All other bearings OK. Thought the bypass stuck so I pulled the pump and the drive in the pump won't turn. Put a spare drive shaft in it and it turns, but takes a lot of force. Pulled the pump apart and the shaft is not scored, but the fit in the pump is very tight. It spun freely when it was put together. Anyone else have this problem? I have a spare pump that turns freely, but reluctant to use it. Any thoughts? Why did only #2 main wipe? Crank was not hurt. Tempted to throw new bearings in it and a new pump and try it again