Some basic guidelines that should be followed before the installation of new 
Piston rings include, checking on the end gaps of the ring, to confirm that the side clearance of the piston ring has been confirmed as well. Position the piston/connection rod assemblies and new ring sets to examine the corresponding piston and cylinder during the measurement of the engine end gap and engine construction. Place the first ring into the cylinder and line it with the cylinder walls by slamming the piston into it, placing the top of the ring at the bottom of the cylinder. If the gap varies at the ends of the ring, stack feeler gauges between the two ends of the ring and keep increasing the thickness until the correct is obtained while ensuring the compression ring is square to the cylinder bore. The feeler gauge should fit in between the ring ends with slight friction; compare the size to the prescribed size; if the gap is incorrect identify the wrong rings. If we found that the gap is a little then do not file the ends of the rings and replace all of them. End gaps are not a problem as long as they are over 0.040 inch, check the correct rings for the engine. Perform the same process for every other ring in the first cylinder and the other cylinders; commit to pairing rings, pistons, and cylinders. Once this is done assess the gaps on the rings and fine tune the ring end gaps before putting them into the pistons; the oil control ring comprises of three parts. Place the spacer/expander into the groove so that any anti rotation tang fits into the drilled hole made on the member. Thus, the lower side rail should be installed without the use of piston ring installation tool to avoid damage and the upper side rail installed in a similar manner. Following the installation of the 3 components of the oil ring, ensure that the two side rails are rotating on the groove. Subsequently, place the middle ring, with the 'stamp here' label upwards and applying the instructions provided in the ring package, do not mix the top and middle ring. Carefully put the middle piston ring into the groove with the help of a piston ring installation tool and the identification mark MUST face upwards and do not widen the gap of the ring beyond what is necessary. Last of all, position the top ring same way with line facing up and follow the process to the rest of the pistons and rings.