In this subsection the general information and diagnostic operations for definition of a condition of the engine are resulted.
It is not always easy to come to a conclusion about expediency of full major repairs of the engine as it is necessary to be based on variety of objective indicators.
The big run is not a sufficient indicator of necessity of carrying out of major repairs, on the other hand, small run does not exclude necessity of carrying out of major repairs. The most important indicator, most likely, is timeliness of current maintenance service of the engine. At timely change of oil and the filter, and also at performance of all other necessary works on service the engine serves reliably throughout many thousand kilometres of run. On the contrary, insufficient on volume or untimely maintenance service can be at the bottom of sharp reduction of a resource of the engine.
The raised expense of oil specifies in deterioration of the piston rings, directing plugs of valves and маслоотражательных caps. It is necessary to be convinced that leaks are not at the bottom of the raised expense of oil, and only after that to do a conclusion about unfitness of piston rings and directing plugs of valves. To define a malfunction plausible reason, measure a compression in engine cylinders. Conduct also tests by means of the vacuum gauge and define character of indications of this device.
Check up pressure of oil a manometre screwed instead of the gauge of pressure of oil, and compare result of check to standard value. If pressure of oil low deterioration radical and шатунных bearings or details of the oil pump can be the reason.
Capacity loss, failures in engine work, a detonation or the metal knocks, the raised noise from газораспределительного the mechanism, specify the raised expense of fuel in necessity of carrying out of major repairs, especially, if all these signs of abnormal work are shown simultaneously. If performance of all adjustments does not lead to improvement unique means of elimination of abnormal work of the engine are major repairs. Major repairs consist in restoration of details of the engine to a condition specified in specifications for the new engine.
At major repairs carrying out pistons and piston rings are replaced, chiseled or хонингуются cylinders. After repair of cylinders which is carried out in a specialised workshop, installation of pistons of the repair sizes is required. Шатунные and radical loose leaves of a cranked shaft, and also a cover of basic necks of camshafts also are subject to replacement, if necessary follows прошлифовать necks of a cranked shaft before restoration of normal backlashes with шатунными and radical loose leaves. As a rule, valves, as their condition at the moment of repair, as a rule, not absolutely satisfactory are subject to repair also.
During engine major repairs repair of such units as a starter, the generator and the ignition distributor also is carried out. As a result repaired engine should possess qualities of the new unit and sustain considerable run without refusals.
At major repairs it is necessary to replace such important details of system of cooling as hoses, drive belts, the thermostat and the
pump of a cooling liquid. The radiator should be surveyed on tightness and cleanliness of internal channels. If you have got the restored engine, or the block of cylinders of an incomplete complete set some suppliers do not give a guarantee on operation of these units without qualitative washing of a radiator. At engine major repairs also it is recommended to replace the oil pump.
Before the beginning of major repairs of the engine familiarise with the description of corresponding procedures that there was an impression of forthcoming amount of works and requirements to them. At observance of all norms and rules, in the presence of all necessary tools and adaptations major repairs to execute simply, considerable expenses of time however be required. Roughly it is required not less than two weeks, especially if for repair and restoration of details it is necessary to address in a specialised workshop. Check up presence of spare parts and in advance take care of acquisition of necessary special tools and the equipment. Almost all works can be executed by means of a standard tooling though more exact measuring devices will be necessary for check and definition of suitability of those or other details. Frequently check of a condition of details carry out in specialised workshops in which also receive recommendations about replacement or restoration of those or other details.
It is necessary to notice that assemblage of units should be carried out with all carefulness in a pure premise to avoid the further refusals of the repaired engine and to provide its reliable work.