After preparations the piston rings for installation, the ring end gaps are to be checked so that the piston ring side clearance is appropriate before the piston rings are fitted. Position the piston/connecting rod assemblies and new ring sets so that they relate to the same piston and cylinder in order to perform the end gap measurement and then for assembly of the engine. The piston has to be used to square the top ring with the cylinder walls before it can be seated near to the bottom of the cylinder. Check the end gap by inserting a feeler gauge under the intake valve and check with the required measurement. If the gap is incorrect, ensure that the correct rings are being employed on the equipment. If it is too small, it has to be increased to avoid interference of the ring ends when in use; gradually file the ring ends externally. It's not a problem as far as the end gap is larger than 0.020-inch, check once more the rings. Do the same up to the remaining rings and ensure that they belong to the same piston and cylinder set. After the end gaps have been inspected, place the rings onto the pistons; the oil control ring is composite of three parts. Place the spacer/expander into the groove; then put the lower side rail in with no need for the piston ring installation tool; do the same with the upper side rail. After installing the oil ring components it is expected that both side rails rotate freely within the groove. The next ring to be fitted is the number two ring; the top of which should be marked to facilitate recognition when in the engine and the mark should face the top of the piston. This should be done using a piston ring installation tool with care being made not to expand the ring too much. Lastly, place the number one ring in the same fashion as the number four ring, with the identifying mark on top, then proceed on putting in the rest of the pistons rings in the same process as the number four but don be so careless as to interchange the number one and number two of the piston rings.
