Sticking Rings?

[Footpounds]

Educate me. When you hear about a certain product that will "free sticking rings" or someone has oil consumption due to sticking rings, what are the rings stuck to? They can't stick to the cylinder wall (can they?) so I'm assuming rings are supposed to rotate on the piston? I don't know.

 

[Bill in Utah]

They are stuck to the lands of the piston.

Rings are supposed to be able to rotate a little. Most have a pin to prevent the ring to rotate 360 degrees.

Bill

 

[tig1]

I have seen rings that were completely locked into the the piston ring groves where dino OCIs were abused. The end result was the outside diameter of the piston was completely smooth. No ring action at all against the cyl. wall. Proper dino OCIs will prevent this or using a good synt as well. Many engines where changed just because of oil coking in the piston ring area.

 

[bepperb]

There is a groove in the piston they sit in, and this groove gets filled with junk.

 

[mechtech2]

Right.
Rings move in and out - they expand and contract.
If the piston grooves [lands] are dirty, the rings can stick. Even though the bores may not be worn, the car can burn oil and run poorly.
This is why some cars respond to ARx and Marvel Mystery Oil treatment.

 

[severach]

Oil can go past the rings long before getting completely stuck. The smooth ring is expected to seal against the smooth bottom surface of the ring groove. The more carbon is in that contact surface the less it seals. Compression is reduced and oil consumption goes up.

I bought a car with an an engine that would not start and had the engine rebuilt. The machinist had to chip the rings out and clean the grooves. The pistons were fine with new rings in clean grooves.

A completely stuck ring will need to be fixed at a machine shop. Sticking rings may be helped by oil additives.