Before installing the new piston rings, the ring end gaps must be checked, assuming the piston ring side clearance has been verified correct. Lay out the piston/
Connecting Rod assemblies and the new ring sets to match them with the same piston and cylinder during the end gap measurement and engine assembly. Insert the top ring into the first cylinder, ensuring it is square with the cylinder walls by pushing it in with the top of the piston, positioning it near the bottom of the cylinder. To measure the end gap, use feeler gauges between the ends of the ring until a gauge equal to the gap width is found, ensuring the ring is square in the cylinder bore. The feeler gauge should slide between the ring ends with slight drag, and the measurement should be compared to the specifications; if the gap is incorrect, verify the correct rings before proceeding. If the gap is too small, it must be enlarged to prevent the ring ends from contacting each other during operation, which can cause serious damage. This can be done by carefully filing the ring ends while ensuring to file only from the outside in. Excess end gap is not critical unless it exceeds the service limit, so double-check the rings for the engine. Repeat the procedure for each ring in the first cylinder and the remaining cylinders, keeping rings, 
Pistons, and cylinders matched. Once the ring end gaps have been checked and corrected, install the rings on the pistons, starting with the oil control ring, which consists of three components. Insert the spacer/expander into the groove, ensuring any anti-rotation tang is placed correctly, then install the lower side rail without using a piston ring installation tool to avoid damage. Place one end of the side rail into the groove and slide a finger around the piston to push it into place, then install the upper side rail similarly. After installing the three oil ring components, check that both side rails can turn smoothly in the groove. Next, install the middle ring, ensuring the identification mark faces up, and follow the instructions on the ring package, as different manufacturers may have varying requirements. Use a piston ring installation tool to slip the ring into the middle groove, ensuring the mark is facing up without expanding the ring excessively. Finally, install the top ring in the same manner, ensuring the mark is facing up, and be careful not to confuse the top and middle rings, then repeat the procedure for the remaining pistons and rings.