* The oil rings are not installed correctly. The oil rings must be installed in the correct order and orientation. If they are not, they can interfere with the piston's movement and cause it to lock up.
* The oil rings are damaged. If the oil rings are damaged, they may not be able to function properly and can cause the piston to lock up.
* The piston ring grooves are damaged. If the piston ring grooves are damaged, they may not be able to hold the oil rings in place and can cause them to move out of position, which can also cause the piston to lock up.
* The cylinder walls are damaged. If the cylinder walls are damaged, they may not be able to provide a smooth surface for the piston to move against, which can also cause the piston to lock up.
If you are experiencing this problem, it is important to troubleshoot the issue and determine the cause before you attempt to install the piston again. Otherwise, you may risk further damage to the engine.
