Today the shipping industry is evolving taking into account contemporary situations dictate terms: it is necessary to increase maritime safety and reduce costs. In the scope of costs reduction, priority is a ships’ operation time increase. Fatigue strength studies with a variety of non-destructive inspection (NDT) techniques are required for in-service engines life extension. Practice shows that fatigue cracking is the main cause of engine damage formation. As cracks are hard to find, usually the defects occur suddenly during the operation, results in the highest hazard. For this reason, it is important as quickly as possible to detect the occurrence of fatigue damage and further control their development. Currently NDT, as ultrasonic, eddy current, liquid penetrant, magnetic, etc. methods have several drawbacks that make it difficult to use in a number of practical situations, the more so that these methods require stopping the engine for control. This paper contains comparison and assessment of NDT. Most of the traditional NDT disadvantages can be overcome through a prospective NDT method - the method of acoustic emission (AE). AE method with a high degree of probability detect defects of fatigue damage and keep track of their development. Presented paper offer the engine intake valve fatigue damage assessment mathematical model based on the AE signal measurement data. The objective is to develop marine diesel engines acoustic diagnostic methodology for the early detection of engine failure to meet the technical condition of the system (Condition based maintenance - CBM) requirements. Study object - 20 cylinder V-type for stroke diesel engine. Subject of research – ship engines diagnostics procesess during operation. Experimentally confirmed feasibility to detect fatigue cracks birth and progress in the engine cylinder head components during operation. Created mathematical model of the AE signal during gas turbulent flow in the cylinder crack. Scientific novelty: 1. Analyzing engine generated noise using acoustic emission method there are possibility to obtain results online. 2. Analyzing engine generated noise using acoustic emission method there are possibility to obtain results online. 3. It is created acoustic emission metodology for engine failure early detection to meet Condition Based Maitenance (CBM) requirements. The dissertation is in Latvian, it contains an introduction, 4 parts, conclusions, list of references, eight attachments, 80 pictures, 6 tables, total 120 pages. The first chapter deals with marine engines disorders and diagnostic methods for analysis. The second chapter describes acoustic emission signal experimental measurement methodology and technical support. The third chapter contains mathematical modeling of the acoustic signal sources in the damaged engine cylinders. The fourth chapter offer results of the ship’s diesel engine diagnostic measurements. Key words: acoustic emission, acoustic emission diagnostic, marine engines technical condition monitoring, mathematical modeling.