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Repair parts and components MOTOR. Changing the rod bearings and main bearings

When deciding on the need to change inserts bearings should be borne in mind that the diametrical wear bearings and crankshaft journals is not always the determining the criterion. In operation, the motor antifriction layer liners interspersed significant amount of solid particles (products of wear abrasive particles are sucked into the engine cylinders with air, etc.). Therefore, these liners, often with little diametrical wear, can cause further accelerated depreciation and rexinforced crankshaft journals. It should also be borne in mind that the connecting rod bearings work in more severe conditions than natives. The intensity of wear slightly higher than the rate of wear of main bearings. Thus, to address the issue of replacing the bearings needed differentiate between main and connecting rod the bearings. In deciding whether to replace the bearings, connecting rod as well as indigenous, should be guided by the following: - In the assessment of ear examination, keep in mind that surface of the antifriction layer is satisfactory if there are no scratches, pitting (On the work surface does not show traces of lead .... bronze gold color) and depressed in the fusion of foreign materials (inclusions); - .... Paint the surface of the antifriction alloy is for rejection; - .... Liners, suitable for further installation engine should be straightening of the day, which provides creation in bed (in a block in the covers of indigenous and connecting rod bearings and a rod) tightness. The presence of tightness liner ensures the necessary heat from the liner, thanks to a better fit to the surface of the liner surface the bed. Inserts that do not have a tightness in their beds, to be replaced; - The permissible diametrical clearance in the bearings crankshaft are shown in table 2. Clearance in the bearings found by calculating the difference between the sizes obtained with metering bore in bed with embedded inserts (Cervix doolzhna be necessary to pull force) and the shaft journal. The required value of diametrical clearance in the bearings during repair the engine in some cases can be achieved without pereshlifovki neck, only the application of new liner nominal size. In all other cases, the necessary clearances obtained by grinding necks of the shaft and installing the appropriate repair liners size. To replace worn or damaged bearings in the spare parts are delivered and vkladyshinominalnogo four sizes of repair. Inserts repair size differ from the nominal size of inserts in a decrease 0.25, 0.50, 0.75, 1.00 mm internal diameter (Table 4). To install these bearings crankshaft journals should be abraded by an amount corresponding decrease. When the application inserts the size of repair does not provide obtaining the necessary clearances in the bearings crankshaft (shaft had been abraded by the maximum decrease), it is necessary to install a new crankshaft inserts with nominal size. For such a case in spare parts kit is 412-1000107-03, consisting of the crankshaft, connecting rod and a set of bearings and indigenous nominal size. Thin-walled interchangeable inserts connecting rod and main bearing crankshaft manufactured with high precision. The required value of the gap in the bearing diametraldnogo only ensured adequate diameter crankshaft journals shaft, obtained by grinding. Therefore inserts in the repair of the engine replaced with new without any adjustable operations and only in pairs. Replacement of the liner of a pair is not allowed. From the above also It follows that to obtain the desired diametrical clearance the bearings are not allowed to file down or prishabrivat joints or inserts bearing caps, burn on these joints details or to place spacers between the liner and the bed. Failure to follow these guidelines leads to what is broken correct geometry of bearings, worse heat pads on them quickly gone. But the most dangerous that the bearing of felled or prishabrennymi lids are not recommended in the future install new liners repair sizes. Spoiled processing of the bearing caps can not be replaced because they were processed at the plant together with the cylinder block or connecting rod. Since the cover bearings are not interchangeable, they are not supplied in spare part, and so the engine is damaged lids can not be subsequent repair. After replacing the connecting rod bearings as well as main bearings assembled motor shall be subjected to run-in.
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