Before installing the new piston rings, the ring end gaps must be checked, assuming that the piston ring side clearance has been verified correct. Lay out the piston/connecting rod assemblies and the new rings to match the ring sets with the same piston and cylinder during the end gap measurement and engine assembly. Insert the top ring into the first cylinder, squaring it with the cylinder walls by pushing it in with the top of the piston, ensuring it is near the bottom of the cylinder at the lower limit of ring travel. To measure the end gap, slip feeler gauges between the ends of the ring until a gauge equal to the gap width is found, ensuring the feeler gauge slides with slight drag. Compare the measurement to the specifications; if the gap is larger or smaller than specified, double-check to ensure the correct rings are being used. If the gap is too small, it must be enlarged to prevent the ring ends from contacting each other during engine operation, which can cause serious damage. The end gap can be increased by carefully filing the ring ends with a fine file, ensuring to file only from the outside in. The end gap should not exceed the specified value. Repeat the procedure for each ring installed in the first cylinder and for each ring in the remaining cylinders, keeping rings, pistons, and cylinders matched. Once the ring end gaps have been checked and corrected, the rings can be installed on the pistons, starting with the oil control ring, which consists of three components. Slip the spacer/expander into the groove, then install the lower side rail without using a piston ring installation tool to avoid damage, instead using fingers to guide it into place. Install the upper side rail in the same manner, ensuring both side rails can turn smoothly in the ring groove and staggering the gaps. The middle ring is installed next, marked to face up toward the top of the piston, and care should be taken not to mix it with the top ring, which is installed similarly, ensuring the mark is facing up. Repeat the procedure for the remaining pistons and rings.
