If you can make the noise go away or change note noticeably by disconnecting spark plug wires one at a time, you've probably got piston slap, not a bearing problem. One or more pistons might have excessive skirt clearance, and is rocking in the bore as the spark plug fires. If that's what's happening, it's mostly just annoying, not an impending disaster.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!