2.4.3. Check of pistons and rods

After removal of pistons and rods it is necessary to spend дефектовку. At presence on details of signs задиров, cracks and their strong deterioration it is necessary to replace. Pistons and rods are necessary for checking as follows:

Fig. 68. Measurement of a backlash of piston rings on height in piston flutes

- To measure a backlash of piston rings on height in piston flutes, establishing piston rings serially in a corresponding flute (fig. 68). To define with the help щупа a backlash between an end face of a ring and its flute. If the backlash makes more than 0,15 mm the ring or the piston are worn out. The nominal size of 0,02-0,05 mm. The maslosemnoe ring can consist of three parts. At such execution of rings to measure a backlash on height it is impossible. In other engines the unary ring is used. On it the same rules, as for компрессионных piston rings extend;

- Serially to establish in cylinders all piston rings from the bottom party картера. The piston to wring out rings downwards approximately on 15 mm. Thanks to it their installation in the cylinder without warps is provided;

Fig. 69. Backlash measurement in the lock of piston rings

- To enter щуп into a backlash between the ring ends, as is shown in fig. 69, for backlash measurement in the lock of a piston ring. Values of a backlash see "Specifications". Backlashes неодинаковы for various engines;

- At too small backlash (for example, on new rings by which also it is necessary to measure), the ends of rings can be processed a file. At too big backlash the ring is subject to replacement;

- To check up piston fingers and plugs of rods on presence задиров. If it will appear that one rod is damaged at least, it is necessary to replace all complete set;

- To check up rods on the correct machine tool on twisting and bend deformation;

- And a nut of rods always it is necessary to replace bolts of bearings of rods — to a reuse they are not suitable;

Fig. 70. The control of a preliminary inhaling of loose leaves of bearings of rods: and — diameter of the loose leaf of the bearing; b — diameter of an aperture of a rod

- The new requirement for the established engines is measurement of value of a preliminary inhaling for loose leaves of bearings of rods. The calliper for this purpose is required. With that end in view rods and covers of bearings connect bolts without loose leaves and tighten nuts the moment 30 Нм (доворачивать on a demanded corner it is not required). To measure width and (fig. 70) the loose leaf шатунных bearings and to write down it. Then to measure internal diameter b шатунного the bearing. To subtract diameter of the loose leaf of the bearing and from internal diameter b. For the engine in volume of 1,0 l the difference should make 0,5 mm. At other engines it can be to 1,5 mm. Otherwise it is necessary to replace loose leaves of bearings.