What Is Piston Ring Replacement? How Is It Done?

This article’s topic is piston ring replacement, which has an important place in engine knowledge. Learning how to replace piston rings means having one more piece of engine maintenance knowledge under your belt.

You can find extensive information about piston rings on the page linked below.
See also: What Is a Piston Ring, What Does It Do? Its Job and Installation

What Is Piston Ring Replacement?

In all internal combustion engines, replacing the piston rings due to problems such as oil consumption or blow-by that develop in the engine for various reasons is called piston ring replacement.

The pistons in your car’s engine move up and down inside a cylinder. The rings on top of the piston provide compression — that is, they help compress the intake air-fuel mixture and, once that mixture is ignited, keep the resulting pressure from leaking past, pushing the piston down.

Over time, your piston and its rings (rings act like collars) wear down, lose diameter, and are no longer able to hold the cylinder pressure properly. Since they’re in direct contact with the cylinder liner, the rings usually wear out before the pistons do. In that case, new ones are fitted.

Before replacing piston rings, the cylinder liners and pistons are measured to check whether they’re still within tolerance. The clearance between the pistons and the cylinder liner should be in the range of (0.2–0.5mm).

When needed, as shown in the picture above, the cylinder is also honed (its inner surface undergoes fine machining), an oversized piston is fitted, and the engine starts holding full pressure and running smoothly and efficiently again.
For our article about honing, see: What Is Honing, How Is It Done

What Does Piston Ring Replacement Do?

The purpose of piston ring replacement is that, if your car’s engine is burning oil, has blow-by, or has lost power, replacing the rings restores the engine to its former strength. This procedure applies to all internal combustion engines. Replacing rings in any ring-based engine — cars, heavy equipment, ships, motorcycles, compressors, generators, and so on — is called piston ring replacement.

How Is Piston Ring Replacement Done?

The key thing to keep in mind during piston ring replacement is that, even though the ring is made of a flexible material, it can still break. To remove and install the ring without breaking it, some points need to be kept in mind.

The video above shows how to replace the rings on a motorcycle engine’s piston. It also covers what to watch out for while doing this, and some common mistakes made during the process.