The ring end gaps should be verified before fitting the new
Piston rings, the piston ring side clearance being checked with the correctness of the piston ring end clearance. Preparing the end gap measurement and assembling the engine, set the piston/connecting rod systems and the new sets of rings to match with the same piston and cylinder. You have to insert the top ring into the first cylinder making sure that it is in line with the walls of the cylinder by pushing it into the cylinder with the top of the piston, and then putting it close to the bottom of the cylinder. The end gap is measured using feeler gauges between the ends of the ring until a gauge matching the width of the gap is located making sure it slides with minimal drag. In case there is not enough gap between the ends of the rings, it needs to be increased to ensure that the ring ends will not collide with each other during engine operation, which can result in severe damage; this may be achieved by filing the ends of the rings carefully outside and then removing the burrs. Excess end gap is not critical until it passes 0.040-inch and it is imperative to check that the correct rings are in place particularly when the engine block has been bored oversize. Proceed to repeat this process to all the cylinders with the matching rings, pistons, and cylinders. After checking and repairing the gaps on the end of the rings, now fit the rings on the pistons, first the oil control ring, which can either be a one-piece ring or a three-piece ring. When three-piece oil rings are used, then place the spacer/expander into the groove, and make certain that any anti-rotation tang is in place. Install the bottomside and topside rail with no piston ring installation tool to prevent damage and make sure that the rails have the ability to rotate freely in the ring groove. Then install the middle ring and make sure that the identification mark is facing up then install the top ring in a similar way, without mixing up the two. And at last do the same with the rest of the pistons and rings.