Cylinder liners are probably the single most undervalued part of an engine as their functions are rarely acknowledged. Besides acting as the facilitators to the engine processes, cylinder liners are also the only devices that can enhance its operations and reduce its internal wear.
But in the due process, cylinder liners bear a large amount of damage that can further aggravate the engine processes. Even the most advanced type of air-cooled cylinder liner is vulnerable to severe wear and tear. Liner damages can be classified into a number of types, some of which are mentioned below:
Gradually Acquired Abrasive Wear
The damages that are incurred as a result of the friction between any two surfaces is called abrasive wear. It is the most common mechanical wear that is also caused in other processes like plowing, micro-slicing, shearing, etc. When the hard particles of the impurities slide between two co-operating surfaces, they create irregularities on these surfaces. Over time, irregularities turn into significant abrasive wear. Colloidal, metallic, oxidic, carbide, and sulfide particles are the common culprits for such damages. To prevent these, liners must be cleaned and dusted with a cloth with regularity.
Damages Due to Poor Lubrication: Adhesive Wear
As the name suggests, these damages are a result of the friction between liner and piston surfaces in the absence of sufficient lubricants at either of the parts’ surface. It is one of the most basic types of cylinder liner wear. Continuous working and operating in high pressure or temperature condition increases the rough interaction of the surfaces, thereby causing increased junction shearing. It is commonly perceived by workmen that air-cooled cylinder liners are not vulnerable to such kind of damages. Though, it is rarely true. The altered mechanism of such liners is no excuse to their affectation.
Eventual Fatigue Wear
Even though it is an unlikely name for a mechanical process, fatigue wear is the foremost process that badly affects the functions of cylinder liners. It is an inevitable wear caused by the overwork of engine components. It can be located in areas of the piston-liner system where their surfaces are in contact with each other. Though in the mentioned case, the transfer of mechanical stresses takes place through the lubricant film applied to its surface. Cracks are the common symptom of such damages.
Chemically Fueled Oxidative Wear
Damages are not merely physical, but also chemically caused. The interacting surfaces of liners and pistons also exchange electrons at the micro level. Such exchanges result in oxidation of the metals. Rust and flaky surfaces on the surface of the cylinder liners, including air-cooled cylinder liner, are clear indicators of such wear and tears. They can at least be prevented.
When the physical and chemical processes act upon cylinder liners at the same time, they result in corrosion. The high temperature, pressure, moisture content, and mechanical stress handled by the cylinder liners become causal factors of such damages. They usually go beyond the physically observable layers of the surface. More often than not, breaking apart of the liners during an operation is caused by a corrosive action.
Air-cooled cylinder liner is the most sophisticated form of liners that are designed with the objective of reducing the amount of internal stress in an engine and for increasing its cooling process. However, despite their appreciable mechanisms, they are equally susceptible to the above-mentioned list of damages.
The essentially similar elemental composition of liners is the primary reason that makes them vulnerable to environmental, temperature, and mechanical factors. Hence, they must be regularly changed and maintained after seeking professional suggestions from technicians.