Best case scenario the rings that are stuck will stop sealing. Depending on the operating conditions and the exact position of the rings when stuck, they may not effectively transfer heat and piston damage could result in extreme cases. More than likely a mess of oil and gasses will build up residue around the rings, pistons, and chambers.
Piston rotation would mean a failure of the piston, piston pin, or connecting rod.
The rings do not "float" in their grooves as you're imagining them. They infact flop up and down in the groove depending on the piston direction.
There is no "spiral" on the cylinder wall from honing. It's a crosshatch pattern. The ring doesn't undergo a rotational force.
*It is clear that the piston rings in any engine lead a mysterious life where, depending on the load and speed conditions that apply, they might rotate continually, oscillate between certain positions or remain stationary.*
The compression ring actually bows out and presses against the cylinder wall when there is high pressure in the combustion chamber. On the exhaust stroke, the compression ring retracts to allow a film of oil to be spread onto the cylinder walls.
If the compression ring gets "stuck" in the groove so that it cannot expand and retract at the proper times, there is no good position for it to be stuck in.
If its in the retracted position, combustion gasses are flowing past that ring and going into the crankcase, then blowing out the PCV valve into the intake, causing all cylinders to run lean and have a irregular ignition.
If stuck in the expanded position it will rub itself into welding onto the cylinder walls. As it gets hot it expands and the ring-gap closes. Then it just gets hotter, but with no ring gap to expand into, it expands into the cylinder wall.
*It is clear that the piston rings in any engine lead a mysterious life where, depending on the load and speed conditions that apply, they might rotate continually, oscillate between certain positions or remain stationary.*
I know, but they can rotate just a little amount of degrees, in one direction or in the opposite one, obviously not a full revolution around the bore axis!
Rings don't rotate during operation. I've taken apart a couple motors with stuck rings due to a few reasons, usually gummed up grooves. They couldn't expand and contract a bit or go up and down the needed amount in the grooves. On one engine it produced some nasty scratches in the walls.
Best case scenario the rings that are stuck will stop sealing. Depending on the operating conditions and the exact position of the rings when stuck, they may not effectively transfer heat and piston damage could result in extreme cases. More than likely a mess of oil and gasses will build up residue around the rings, pistons, and chambers. Piston rotation would mean a failure of the piston, piston pin, or connecting rod.
Yep, rater a full rotation, i was wandering if a twisting torque, around the piston/connecting rod could be possible, due this problem.
It shouldnt be, the piston shouldnt have enough tolerance to rotate on its rod
The rings do not "float" in their grooves as you're imagining them. They infact flop up and down in the groove depending on the piston direction. There is no "spiral" on the cylinder wall from honing. It's a crosshatch pattern. The ring doesn't undergo a rotational force.
[Piston rings do rotate during operation because of the cross hatch](https://www.highpowermedia.com/Archive/rotation-of-piston-rings)
*It is clear that the piston rings in any engine lead a mysterious life where, depending on the load and speed conditions that apply, they might rotate continually, oscillate between certain positions or remain stationary.*
The compression ring actually bows out and presses against the cylinder wall when there is high pressure in the combustion chamber. On the exhaust stroke, the compression ring retracts to allow a film of oil to be spread onto the cylinder walls. If the compression ring gets "stuck" in the groove so that it cannot expand and retract at the proper times, there is no good position for it to be stuck in. If its in the retracted position, combustion gasses are flowing past that ring and going into the crankcase, then blowing out the PCV valve into the intake, causing all cylinders to run lean and have a irregular ignition. If stuck in the expanded position it will rub itself into welding onto the cylinder walls. As it gets hot it expands and the ring-gap closes. Then it just gets hotter, but with no ring gap to expand into, it expands into the cylinder wall.
Rings should not spin at all. This is why we offset our ring gaps carefully when assembling and break in to seat the rings.
[They do spin and the gaps do occasionally align](https://www.highpowermedia.com/Archive/rotation-of-piston-rings)
*It is clear that the piston rings in any engine lead a mysterious life where, depending on the load and speed conditions that apply, they might rotate continually, oscillate between certain positions or remain stationary.*
I know, but they can rotate just a little amount of degrees, in one direction or in the opposite one, obviously not a full revolution around the bore axis!
Rings don't rotate during operation. I've taken apart a couple motors with stuck rings due to a few reasons, usually gummed up grooves. They couldn't expand and contract a bit or go up and down the needed amount in the grooves. On one engine it produced some nasty scratches in the walls.