Guide

Piston Rings

Piston rings are made from spheroidal (gray) cast iron or steel. Steel rings are differentiated into chromed with a martensitic microstructure and spring steel. Depending on the requirements of the engine and emission standards, the appropriate material is selected.

Piston Rings by Dimension

Piston rings are a key element in engine design. Their numerous tasks are essential for the proper functioning of the combustion engine. Therefore, piston rings must be precisely matched to a specific engine, not just chosen by size.

Remedy/Method/Product for Seized Piston Rings

Seized piston rings are one of many reasons for engine oil burning in the engine. The most effective way to address this issue is to repair the engine and dismantle the rings. Unfortunately, this is a costly method. Therefore, another way is to use chemicals to dissolve (flush out) the buildup from the piston grooves. Special chemicals or home remedies like kerosene can be used for this purpose.

Types of Piston Rings and Their Placement

Piston rings are differentiated by their cross-section and application in the piston. We distinguish rectangular, trapezoidal, semi-trapezoidal, conical, three-piece, and two-piece (with a spring) rings. Based on application, there are compression rings, oil scraper-compression rings, and oil rings.

Which Way to Install Piston Rings?

During the installation of piston rings, it is important to check for any “UP”, “TOP”, or manufacturer’s markings on the ring. If any of these symbols are present on the piston ring, it should be installed towards the piston head (towards the cylinder head).

When to Replace Piston Rings?

Piston rings should be replaced when the engine starts to emit excessive exhaust smoke or when increased engine oil consumption is noticed (beyond the manufacturer’s acceptable level). However, smoke or oil consumption does not guarantee that worn piston rings are the problem, but it is one of the main causes.

How to Install Piston Rings?

Piston rings should be installed on a cleaned piston, after measuring whether the old piston is suitable for reinstallation. Additionally, only piston ring pliers should be used for the installation, ensuring correct placement of the rings and avoiding micro-cracks.

How to Seal Piston Rings?

Piston rings should move freely in the piston groove. They should not be sealed in any way. If the engine shows signs of ring wear, such as smoking or oil consumption, an engine overhaul is required.

How to Choose Piston Rings?

Piston rings should be selected by specialists to avoid incorrect sizing. First, find the engine code on the vehicle’s nameplate (on the engine block, hood, or spare wheel well). Then, determine the version of the vehicle (European, American, or Asian) and all vehicle data (brand, model, engine capacity, power, year). All this information is essential for the correct selection of piston rings, but always verify against the previously removed rings (from the engine).

Piston Rings – What Should the Gap at the Joint Be?

Piston rings expand during engine operation due to temperature, so a gap at the ring joint is necessary. The value of this gap varies depending on the piston design. In many cases, a significant gap can be observed in a new oil scraper-compression ring (commonly known as the second ring) and can even be as much as 1 mm. This is not a manufacturing error.