Engine wear - Fundamental shapes

Engine uptime and reliability are only very rarely limited by sudden component failure caused by material strength defects. The increased choice and performance of materials, modern calculation methods and component inspection techniques are increasingly eliminating the risk of serious incidents.

On the other hand, engine life and performance are limited by wear phenomena or lubrication failures such as seizure, scuffing, abrasion, pitting, fatigue spalling, ring sticking, oil thickening due to oxidation, accumulation of hot deposits (carbon, varnish, etc.) or cold deposits (sludge), and so on.

One of the essential functions of motor oil is to combat wear and tear, and prevent the engine from coming to a standstill, with all the resulting inconvenience for the user.

The consequences of wear on motors can be :

• a sudden breakdown resulting in temporary immobilization or even permanent disablement of the engine;

• loss of performance that can hinder users by depriving them of expected services, or simply by causing a loss of driving pleasure;

• higher operating costs due to excessive fuel or lubricant consumption, more frequent oil changes (due to oil pollution) and overhauls (adjustments and replacement of components) and, last but not least, reduced engine life.

Naturally, engine wear does not depend solely on the role played by the lubricant, but also on many other factors, such as the technology of the assembly and of each individual part, their metallurgy, manufacturing tolerances, operating conditions and their degree of compliance with the manufacturer's specifications, the quality of the fuel used, combustion settings, climatic conditions such as ambient temperature, atmospheric pressure, humidity and/or corrosiveness of the air (sea air) or abrasiveness of the atmosphere (dust).

Despite ever-increasing engine performance and growing environmental (increasingly advanced pollution control) and economic constraints (lower production costs and fuel consumption), engine longevity is constantly on the rise, thanks both to advances in engine technology and the use of higher-performance oils.

But while the average life of engines is increasing, the wear-sensitive components - which can vary from one type of engine to another - are not always the same today as they were yesterday, and will certainly evolve in the future.