what is the first sign of main, rod, and cam bearing failure. Will it make noise, will you lose oil pressure, and if one does spin or goes out, how long will it take for it to destroy the motor? If you spin a rod bearing, will there be any signs? will you hear it. if it is spun, what are all the warning signs?
Spinning a bearing is itself destructive. It doesn't take any additional running time. Engine damage was already happening before the bearing spun. "Usually" the first signs are reduced oil pressure and/or noisy valvetrain. Engine destruction is already in progress when this happens. If a rod bearing poops the bed, you'll usually hear knocking which MIGHT be reduced if you pull the plug wire off that cylinder.
My experience has been - on the street and not racing - the rod will start knocking lightly and get louder soon thereafter. Soon thereafter meaning within minutes. I lost a rod bearing in a built Olds engine in a 50 Ford coupe on the freeway and chose to keep going cuz I had a spare crank et al at home. Sounds dumb and maybe it was, but if I'd stopped where the knocking started Sweetie would never have found me and I chose to go to a place she was familiar with. I did notice that the engine carried in excess of 40# oil pressure right up until it locked up on an off-ramp. Once I let off the gas . . . fini....
