Hello Enginetech friends, in this blog post we will review a little bit about piston rings, as well as how to choose the correct ones for your vehicle. Piston rings act as a seal, sealing the gases in the combustion chamber, controlling oil on the cylinder wall, and transferring heat from the piston to the wall. We offer high quality, ready to install piston rings for a wide variety of applications.
When purchasing pistons from Enginetech, be sure to read the notes associated with those pistons, as this will give you the correct part number for the required ring set.
If you are reusing the original equipment pistons or another manufacturer, you will need to go directly to the piston ring section and choose your rings accordingly, paying close attention to the notes. It is important to remember that not all aftermarket pistons have the same ring stack as the original equipment.
Enginetech piston rings are sold in sets, enough for a complete engine and typically has three types of rings. Usually, this is a top compression ring, a second oil scraper ring, and an oil control ring. The top compression ring controls gases in the combustion chamber and helps dissipate heat from the piston to the cylinder wall. The second oil scraper ring is the lower compression ring that is the 2nd line of defense. It helps with sealing gases, aides in heat transfer, and scrapes oil from the cylinder wall. The oil control ring, just as the name suggests, controls the oil on the cylinder wall and helps with heat transfer as well.
Enginetech offers standard cast iron rings as well as premium molybdenum, chrome, or high alloy steel. Our cast iron rings all have a part number that beings with “R” while the premium rings all begin with “C”, “M”, or “S”. The top compression ring material is what makes the difference between a standard and premium piston ring. We select the appropriate type of ring depending on the application and environment of the ring. In many engines, either standard or premium are acceptable, and you can choose between the two based on your personal preference.
ET piston rings come pre-gapped, however, it is always best practice to check your end gap before installation. We recommend a minimum of .0035” per inch of cylinder diameter. For example, a 4.000” bore would require a minimum end gap of .014” (.0035 x 4 = .014). Be sure to check your end gap at the bottom of the cylinder, below the ring travel area. This area will not have wear from previous piston ring travel, thus giving an accurate ring gap reading. If the ring gap is correct in this location but too large in the top of the cylinder, you will need to bore the block to the next size up. Too much end gap causes loss of compression and horse power. However, not enough can cause the ends of the rings to butt together, which would result in catastrophic engine failure.
After choosing the correct rings, you will be ready for installation, which will be covered in a later blog. Please resist the urge to rip open the box and dump the rings on your work space as the box separates the rings into the appropriate positions. If you have already made this common mistake, don’t worry, we can help.
If you chose cast iron rings, it will not be as easy to tell them apart, so it may be best to contact customer service for assistance. However, if you chose premium rings, you can easily identify the top ring by the shiny outer facing while the 2nd ring is a dull grey. The oil control rings are easy to differentiate as most of them are 3 pieces with two scrapers and a flex vent expander.
Please be sure to keep an eye out for our next blog on how to install your rings!