Question a friend asked me today, and I'm not sure what the answer is, so here goes.

When a rod bearing in a piston fails, the engine develops a knock and potentially throws a rod onto the side of the highway.

When an eccentric shaft bearing fails (do they fail? I assume it could.), what happens? Does the rotor start destroying the eccentric shaft itself? Does it mess up the housings? I'm uncertain, call me a noob.

~Devon

 

Most of the load on the eshaft bearings is radial. You don't get the pounding load that a piston rod exerts.

 

Oh, ok. That makes a lot of sense, probably should have thought of it myself.

 

They can fail, but from what I've read they usually fail either by the bearing "spinning" in the bores they are pressed in & losing concentricity or coming partway out the bore, or by the softer bearing face material "blowing by" and creating a huge oil bypass.

If the bearing got mauled enough, you could conceivably get rotor strikes on the side or rotor housings, but before it gets that far you'd probably sieze due to oil starvation.

 

when the rotor bearings fail, the engine seizes.

 

ive seen a couple of motors that lost a main bearing, and they will knock, cause the rotor can flop around

 

If I change to my old phone, I could upload a ton of photos of this.