Q: What is the importance of checking the ring end gaps before installing new piston rings?
A: When preparing to install new Piston rings, you have to check the ring end gaps before making the assumption that the piston ring side clearance has been verified. While arranging the piston/connecting rod assemblies as well as the new ring sets should be done in a way that would permit matching of rings with its respective piston and cylinder for testing of end gap and engine assembly. To begin with, push number one top ring into first bore until it moves all way down before squaring it against cylinder walls with piston top. Take measure of the end gap by inserting feeler gauges between ends of the ring; then you pull them until one can find a gauge, which fits into gap with slight drag. In case of incorrect gaps, ensure rings are properly compatible before proceeding further. If gap is too small file off ring ends carefully using a fine file, but anything within 0.040 inch does not matter much whether it needs adjustment or not. Repeat this process for each ring in all cylinders while keeping rings, pistons, and cylinders matched. The next step involves fitting installed rings once their end-gaps have been checked and put right as necessary. Start with oil control ring which consists of three parts and insert them one at a time beginning from spacer/expander ensuring right positioning when there is anti-rotational tangue. Install side rails loosely on top groove so that they will be able to turn freely but without using any tool meant for installing piston rings. Then install number two (middle) ring such that mark faces upward while ensuring you are using a proper tool for installing piston rings. Lastly follow suit by installing number one (top) ring in same manner ensuring mark is orientate correctly being careful not to confuse between top and middle during this entire procedure. Repeat these steps for all remaining pistons and rings.