Can you post up some more specifics?
How/Where did water get into the engine? Did you ever have the engine stall? Hard start?
I can tell you a past experience from the mounds.. stalled the engine in deep water. Was hard to restart, as the exhaust was filled with water.
No water got into the oil, but the hard starting put a lot of fuel into the cylinders, which washed down, and got into the crankcase. The extra gas thinned the oil.. Drove just back to the lot and put it on the trailer. Changed the oil, circuilated it, let it sit, changed it again(including the filter twice)
After that, it was like you mentioned.. no oil pressure at idle, noise from up top, and burning oil..
The oil thinned out due to the gas, and just ate up the bearings and the valve seals.