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2. Carefully move apart the lock of the top kompressionny ring and remove it from the piston at the top. Operating in a similar manner, remove the remained second kompressionny ring, then maslosjemny. In order that in the course of removal of a ring did not fail in located above a flute, use pair old lezviyny щупов. Try not to scratch rings a piston surface. Remember that rings are made of rather fragile material and at excessive expansion can break. Do not forget that about keen edges of piston rings it is easy to cut fingers. Pay attention to that fact that the maslosjemny ring consists of three separate parts - a dilator and two lateral sections. All rings should act in film at the top the piston. If old rings are in good repair and are subject to further use, at assembly they should be established strictly on the former places. Release from rings pistons of all assemblies. |
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3. Carefully scratch out coal deposits from the top part of pistons. After the main layer of deposits will be removed, it is possible to use a manual wire brush, or an emery paper. Try not to mention during cleaning piston metal as it can be easily damaged in view of the softness.
4. A fragment of an old ring clean piston flutes, having removed from them the accumulated coal deposits. Be careful, try not to damage walls and a bottom of flutes. Do not cut fingers.
5. Having finished cleaning procedure, wash out pistons and rods in kerosene or other suitable solvent, then carefully dry. Make sure of passableness of maslovozvratny openings in flutes under installation of piston rings.
6. If walls of pistons and a mirror of cylinders are in a satisfactory condition (are not damaged and are moderately worn-out), and the block of cylinders does not need a pro-point (see. Cleaning and check of a condition of the block of cylinders/case of the engine), at assembly can be used old piston rings. Normal wear of pistons is shown in the form of a uniform wipe of persistent surfaces in the vertical direction and accompanied by an easy weak point of landing of piston rings in the flutes.
7. Attentively examine pistons on existence of cracks in regions of skirts, installation sites of piston rings and round openings under a piston finger.
8. Pay attention to defects such, as teases and attritions on surfaces of a skirt, a hole in the bottom and прогары on its edges. Strong damage of skirts of pistons testifies to frequent overheats of the engine, and also appear as a result of violation of correctness of process of combustion of an air and fuel mix. It is necessary to check carefully a condition of components of systems of greasing and cooling. Teases on lateral surfaces of pistons point to the admission of gases bypassing piston rings. Holes and прогары in the bottoms of pistons also are signs of deviations in the course of mix combustion (too early ignition, a detonation, etc.). In any case, in order to avoid recurrence, the reasons of the revealed violations should be defined and eliminated.
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It is necessary to check also serviceability of functioning of ignition/TNVD system and a condition of fuel nozzles. |
9. Corrosion of pistons in the form of cavities testifies to penetration of cooling liquid into chambers of combustion and/or an engine case. The reason should be besides revealed and eliminated.
10. On engines with the aluminum block and "wet" sleeves possibility of replacement of pistons in an individual order is absent. The structure of a replaceable set without fail includes also new piston rings and sleeves of cylinders (see. Cleaning and check of a condition of the block of cylinders/case of the engine). For engines with the pig-iron block the set of new pistons can be ordered in Citroёn company service center.
11. Attentively check rods on existence of cracks around the top and bottom heads. Estimate extent of deformation of crossing points of rods. The probability of damage of rods is very small, if only there was no jamming and a strong overheat of the engine. Thorough check of a condition of rods can be made only in the conditions of a car-care center workshop with use of the special diagnostic equipment.
12. On all engines before assembly it is necessary to make replacement of nuts and bolts of fastening of covers of the bottom heads.
13. On all petrol engines piston fingers are planted in the top head of rods внатяг therefore procedures of removal and installation of pistons should be made by specialists of car repair shop, at whose order there is the corresponding equipment. Track, that in case of replacement of pistons the replaceable answered on dimensional group to diameters of cylinders.
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Developers of the car do not recommend to make dismantling of shatunno-piston groups. In case of need make replacement them assembled. It is not necessary to establish the new piston on an old rod and on the contrary. |
14. On diesel engines piston fingers have floating landing and are fixed by lock rings. Procedure of removal of pistons from rods is described below.
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18. Attentively examine a piston finger and the top head of a rod on existence of signs of wear and damages. In case of strong wear the finger changes complete with the landing plug. Replacement of plugs demands use of a special press and lies outside the limits of qualification of the average amateur mechanic. The facet should be accurately removed from the new plug.
19. Need for replacement actually rods can result from engine jamming. Try to estimate visually parallelism of an arrangement of the planes of heads of a rod. For more detailed check it is necessary to deliver rods in a car-care center workshop.
20. Check a condition of all components, replaceable details should be ordered only in firm Citroёn company service centers. New pistons are delivered complete with piston fingers and lock rings. However, a lock ring can be acquired and in an individual order. |