[epapp]

Yes, definitely.

But I don't have a lift so I can only get at the front of the engine to probe while its running (not going to start it on jack stands).

I feel that someone on here has heard something similar, with all the people that take apart engines around here.

Is there anything I missed that spins about ^^that speed, based on what you hear? When I get home I'll run the recording through a FFT in matlab and find the frequency of the sound in the loudest area, and if its a bearing, I might be able to determine which one based on the ball passing frequency of each bearing in the engine....ideal** ball passing frequency that is..

EDIT: the frequency is ~2700-2800Hz, at different points in the recording (engine RPM is different at somepoints). I guess this means its most likely tied to the crank, unless the cams/scavenge pump turn 1:1 with the crank after all the different ratio changes?