Q: How to install new piston rings on Nissan Xterra?
A: Make sure you have checked the clearance that exists between the side of the Piston and rings before installing piston rings. Organize the assembly of pistons/rods and new ring sets to correspond with the same cylinder and pistons for end gap measurement during engine installation. Fit the first cylinder with top (number one) ring, by pressing it down using its top thereby aligning it with cylinders walls. Place that ring towards the bottom of a cylinder since some measurements should be taken at this location. For end gap measurement, use feeler gauges and locate a gauge that slightly drags upon closing it, which is essentially similar to the width of the opening when completely shut. At any rate, compare this value to specifications; if it is beyond or below those values you need to have correct rings at hand before continuing on your way. If the gap is too small, either file them in order to fit or replace them depending on their material and type. The maximum specified end gap will depart from excess end gap, which is not as critical unless greater than 0.040-inch. In case filing becomes necessary, files should be used carefully in cutting up edges around ring gaps. Keep all parts matched while going through all cylinders for each ring repeatedly doing this task until completion Once you are through with checking or correcting gaps in ring ends, commence installing rings onto pistons Begin with oil control ring by inserting expander/spacer into groove making sure anti-rotation tab (if present) is properly positioned and install side rails without using any ring installation tool Verify smooth movement of lower and upper side rails within a groove meant for a ring The stamp can typically be found toward number two (middle) rings; insert it facing upwards into a piston with extreme caution not to overexpand these while putting them on Take care also not to mix up different cross-sections between upper most part marked "TOP" and one embossed "2ND", which designates number one (top) ring. All pistons and their rings will be subjected to this procedure again.