What exactly happens, what caues it, and how can you tell that you did it. I hear about it all the time on a camed car and was wondering what can be done to prevent it/fix it. I am planning to put a cam in my car and it will have approx 100K on the motor. Thanks!!

 

Basically, the two piece bearings on the rods or crank get worn down due to poor oil circulation, high operating temps, contaminated oil (junk in it), ect ect. One side "spins" under the other, causing a gap, which is where you get the knocking from. they chew themselves up, spreading bits of metal all over the inside of the motor. Not cool.

Preventative?? Regular oil changes, keeping the operating temps down, hence keeping the cooling system in good working order.

As for a cam causing it, with a cam you're putting a greater strain on the engine than before. It's completely possible that the motor was weak to begin with.

 

So if it happens, your block is pretty much toast?? Or is there a way(cheaper) to fix it??

 

The block should be salvagable, but best case is you hone the cyl walls, turn the crank, and replace all bearings. This is the time most people go 355 or 383

 

Not necessarily. Spun bearing means the to bearing halves spin around so the gap between them is no longer where the caps/block or cap/rod meet.

This movement misaligns the bearing holes with the holes in the block, causing your low oil pressure.

Lack of oil is the number one cause of bearing failure IMO. Not **** in the oil, cause the filter will catch most of it and the rest will pass right through.

On the block being salvagable, in most cases yes, in some no. Stop running it if you think somethin is wrong.