Before pulling the motor we did a cold compression test. Results were 110 to 115 lbs. in each cylinder. We were hopefull that the bottom end would also prove to be good -- no such luck. The oil pan was filled with at least two inches of sludge and the oil pick up was coated with sludge, not a good sign. Checking the connecting rod caps with my hands I could feel them moving, now I know why it was knocking.