A piston has grooves which annex been section into the side of it to clinch the piston's three rings. The grooves are known as "ring lands." The purpose of the rings is to seal the combustion chamber. The most common symptom of worn piston rings is excessive oil consumption, which results when the rings are no longer able to effectively prevent the engine's oil from entering the combustion chamber.
Removing the Existing Rings
Each of the piston's three rings are removed from the top of the piston. Beginning with the upper ring, lift one end of the ring out of its groove and slowly easy the rest of that ring out of its ring land. The middle of the three rings should be removed next in the same manner, followed by the bottom ring.
Checking Ring Gap
Before installing the replacement piston rings onto the piston, it is first necessary to ensure that that ring gap is correct. To check the ring gap, insert only one ring at a time into the cylinder bore. The ring can be pressed into the cylinder bore easily using the top of the piston. Repeat the installation for the remaining two rings.
Positioning the Rings
After the rings are all within their respective grooves, each ring must be arranged in such a way as to ensure that they will properly seal the cylinder. First, note that the cylindrical piston pin located underneath the piston runs lengthwise under the piston. Refer to the engine's specification's manual to determine what the proper gap is, then use the feeler gauge to check that gap. If the gap is too small, the two ends of the rings can be shortened with a file.Fitting the Replacement Rings onto the Piston
Once the proper gap is confirmed, the rings are ready to be installed onto the piston. Because the rings can be easily broken, proceed with patience and care. Hold the bottom ring over the top of the piston, then pull apart the ends of the ring just enough for the ring to fit over the head of the piston. Gently work the ring down to the bottom ring land. Note the gap which exists between the ends of the ring. It is this gap which must be measured. The tool used to measure this gap is called a feeler gauge, and consists of metal blades of varying thicknesses.
The gap of the top ring should be positioned over one end of the piston pin. Position the gap of the middle ring over the opposite end of the piston pin. Position the gap of the bottom ring so that it is at a 90-degree angle to the piston pin.
Installing the Piston Into the Cylinder Block
The actual installation of the piston is perhaps the easiest part of the piston ring replacement process. The first thing to note is the arrow which has been stamped into the top of each piston. The piston must be installed so that this arrow faces toward the front of the engine. Use a ring compressor to compress the rings into the piston. Slowly lower the piston into its cylinder while slowly applying and releasing pressure on the ring compressor until the piston fits entirely into its bore.
