Spun Bearing?

[moper]

The switch is interesting. but if it cuts your car out at 6000rpm, by the time you realize what happened and get the car in nuetral or slow down, the damage is done. Bearing crush is a crutial part of setting clearances, and like was said, the bearing must make good contact between the bore and bearing shell or it overheats and distorts.

[resq302]

so how does one end up with a spun bearing, what are the causes of it, how can one know that a bearing has spun?

[71chally416]

Usually oil starvation or detonation. Detonating a motor will take the "crush" out of the bearings and they will no longer have that spring fit that holds them in the rod caps and main bearing saddles. At that point the only thing holding them in position is the little bearing tabs.
If you don't have a good rear baffle in your oil pan the oil will climb up the back of the pan (they are center sump on Mopars) and uncover the pickup. It will then either starve the pump or the oil will be filled with air bubbles.

[moper]

that about covers it... Oil starvation, whther it be a cause or effect...

[resq302]

so basically, if you have low or zero oil pressure, you have a spun bearing somewhere?

[71chally416]

Probably an injured one that will fail at some point. 

[moper]

No, low oil pressure (or none) could be from a lot of things. The spun bearing in particular is the affected part.. not the cause of the problem. What makes  abearing spin is the breakdown of the hydraulic wedge of oil between the bearing surface and the crank surface. What makes the wedge break down is the cause. The spinning is the affect.