What is a rod bearing (where on the rod is it), and what does it mean when the bearing spins?

 

It's sandwiched between the connecting rod and the crankshaft. The connecting rod attaches the rotating crank to the reciprocating piston. It is a two-piece design and sits in a specific orientation. If it jumps out of this orientation, usually due to excess friction, the bearing is said to be spun... spun out of it's static cradled position.

 

Ok, so there isn't actually a physical bearing (like a ball bearing or a friction bearing or something) in there, the word refers more to the position of the rod and how it's connected to the crankshaft, is that correct?

 

it's a bearing, but if you were looking at it you would think it looked like a thick shim.

 

nope. no physical bearing.

the 2 pieces form a type of clamshell around the connecting rod.
Look up "plastigage" you'll find a better description.

 

Here's a picture of Porsche rod bearings (911):

 

The generic term is journal bearing, I believe.

If you look closely at the picture, you'll see the little tangs that hold the bearing in place in the rod and rod cap.

 

Ok got it thanks guys.

Me = less dumb now