Piston rings

What are piston rings?

Piston rings are metal rings that fit in the grooves of the piston in an internal combustion engine. They serve three main functions:

1. Sealing: Piston rings create a tight seal between the piston and the cylinder wall, preventing the escape of combustion gases and ensuring efficient power generation.
   
2. Oil Control: The oil scraper spring, as the name implies, scrapes the oil on the cylinder wall back into the crankcase. This reduces oil consumption. These springs are often called “the third ring” because they sit in the lowest groove of the piston and most pistons have 3 springs.
   
3. Heat Transfer: Piston rings aid in transferring heat from the piston to the cylinder wall, helping to maintain optimal engine temperatures.

How to mount a piston ring?

Mounting a piston ring requires careful handling to ensure proper installation and function. Preparing the work area and organizing the necessary tools will help with efficient installation. Tools such as a piston ring compressor and piston ring pliers are highly suggested to install each piston in the engine. Wilmink offers these products in their product range. Ensure each piston and all piston rings are clean and dirt-free before you begin the installation process.

Each ring will fit around the piston and then will slide into the groove on the piston. Most engines have specific top, middle, and bottom rings, and are often marked or designed differently to suit their function. Once all rings are installed on the piston and aligned correctly, use the piston ring compressor to gently install the assembled piston into the engine cylinder.

What types of piston rings are available?

Piston rings come in several types, each designed for specific functions and engine requirements. The main types include:

1. Compression Rings: These are usually found at the top of the piston and create a seal between the piston and cylinder wall, preventing combustion gases from escaping. They are critical for maintaining engine power and efficiency.
   
2. Oil Control Rings: Located below the compression rings, these rings help regulate oil consumption by scraping excess oil off the cylinder wall and directing it back to the oil sump. They prevent oil from entering the combustion chamber, reducing smoke and emissions.
   
3. Cast Iron Rings: Commonly used due to their durability and wear resistance, cast iron rings are often found in most engines.
   
4. Steel Rings: These are typically used in high-performance engines due to their strength and ability to withstand higher temperatures and pressures.
   
5. Chromed Rings: These feature a chrome coating for improved wear resistance and reduced friction, often used in engines that require high performance and efficiency.
   
6. Tapered Rings: These have a tapered shape to improve sealing and reduce oil consumption. They can be found in some modern engines for better performance.
   
7. Flat Rings: A more traditional design, flat rings may not seal as effectively as more advanced designs.
   

Each type serves a specific purpose and is selected based on the engine’s design and intended use. Wilmink Engine Parts offers multiple piston ring options from brands such as MAHLE, Goetze, and our Wilmink Engine Parts private label.

When does a piston ring need replacement?

Piston rings may need replacement in several situations including increased oil consumption, loss of compression and loss of engine performance. Following the manufacturer's specifications and guidelines during installation will ensure that the rings are oriented correctly and seated properly in their grooves.