4.3. Engine major repairs - the general remarks
It is not always easy to come to 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 not -
Time maintenance service can be the reason of sharp reduction of a resource of the engine.
|2.1 Check of pressure of oil
The raised expense of oil specifies in deterioration of the piston rings, directing plugs of valves and маслосъемных
caps. It is necessary to be convinced, that leaks are not the reason 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 probable cause of defect, measure a compression in engine cylinders (section 2 see). Necessity of a partition of the engine depends first of all on spent maintenance service of the engine, replacement of oil and filters. The high expense of oil testifies to deterioration of piston rings and valves if its reason is not oil leak. Also check up pressure of oil (2.1
). The capacity loss, unstable work of the engine, knock and the high expense of fuel also testifies To necessity of a partition of the engine.
For scoping of forthcoming works check up a compression in engine cylinders (section 4 see). Conduct also tests by means of the vacuum gauge and define character of indications of this device (section 3 see).
Check up pressure of oil a manometre screwed to the place 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, •указанного in specifications for the new engine. At major repairs carrying out pistons and piston rings are replaced, chiseled or хоннингуются cylinders. After repair of cylinders which is carried out in a specialised workshop, installation of repair pistons is required. Шатунные and radical loose leaves коленвала, and also covers of basic necks of a cam-shaft also are subject to replacement, if necessary follows прошлифовать necks коленвала 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.
The remark. 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 (see Гл.3). If you have bought the repair 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 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. On replacement or restoration of those or other details.
The remark. To address in car-care centre workshops follows only after full dismantling of the engine and check of a condition of all details, especially the block of cylinders to solve which operations on service and repair century of workshops will be carried out.
As the condition of the block of cylinders is the defining factor of decision-making on its further repair or about purchase new (or repair) the block of cylinders to buy spare parts or to carry out operations on machining of accompanying details follows only after careful check of its technical condition. Make it a rule, that the true price of repair is time, - then it is not necessary to pay for installation of the worn out or restored details.
In summary we will notice, that assemblage of any 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.