The piston must be connected to the proper connecting rod and that needs to be done by a professional with the help and an arbor press. Piston rings should also be new and in the correct size to fit the piston being used and their fit is very important for the performance of the rebuilt engine. Before fitting piston rings, the ring end gap for each ring should be measured and the piston rings should be grouped into sets with a top ring, a second ring and an oil control three piece ring. Place one top ring approximately ¾-inch below the upper limit of ring travel and must be perpendicular with the cylinder bore by using the top portion of a piston. If with a feeler gauge, you cannot get the distance between the two ends of the ring sufficient, replace the present one with another top ring. Do the same for all other top rings and, if necessary, file the ends of them to shape. Also, it is important to measure the end gap of each second ring, as well as oil control rings. Refer to figures 3 and 4 and roll each piston ring on the piston to verify that none of the rings bind in their grooves; if the rings have been distorted, replace them. It is essential that the gaps are aligned correctly to the cylinder bore when installing the piston rings and this can be done with a piston ring expander if available or thin strips of tin if the expander is not available. Place the bottom oil ring spacer and its parts to specify the positions of the gaps for the steel oil ring rails. Last of all, inspect the fit of the piston rings into their grooves with the blade feeler gauge and rotate the piston around to make sure there is enough gap and replace or adjust the rings correspondingly.