The paper investigates the complexity of the measurement process in the production, maintenance, and optimization of four-stroke internal combustion engines. Focus is placed on various measurement methods and techniques, including manual and automated measurement, software applications, and relevant standards and regulations. The paper analyzes key performance indicators (KPIs) and performance, emphasizing the importance of precise measurements during the engine repair process. Special emphasis is placed on processing engine parts, such as the engine block, through techniques such as pressing, turning, and honing. The various materials used in these processes are described in detail, exploring their specificities and applications. The case study of the turning and locksmith trade "Đino" provides an empirical insight into the application of theory in practice, demonstrating the steps of deviation measurement and machining. The example of the repair of a PERKINS D 4.203 diesel engine clearly shows the importance of precision measurements, showing the procedures for disassembly, removal of old parts, and installation of new ones. Turning and honing are carried out with extreme precision, resulting in longer engine life. The total repair amount of 300.00 euros confirms the economic profitability of the engine repair. The paper concludes that measurement precision and processing quality are key factors for the successful repair of four-stroke internal combustion engines, contributing to the sustainability and longevity of the engine and saving resources.