1. Previously shatunno-piston assemblies should be carefully cleared. Rings are necessary for removing from pistons.
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Piston rings are subject to replacement without fail. |
2. By means of the special adaptation remove rings from pistons – try not to damage walls of the last casually.
3. Scratch out from the bottoms of pistons traces of coal deposits. After removal of the main layer of deposits, smooth out a surface manually a wire brush or a piece of a fine-grained emery paper.
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At all do not use for cleaning made of a soft material and pistons easily subject to an erosion wire nozzles to an electrodrill! |
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4a. By means of the special adaptation clean flutes under installation of rings on pistons (see an accompanying illustration). |
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4b. It is alternatively possible to use for this purpose a fragment of an old piston ring (see an accompanying illustration), however be careful – do not scratch a bottom and walls of a flute and do not cut fingers. |
5. Having removed the main deposits, wash out shatunny assemblies by solvent and carefully dry them, whenever possible with application of the compressed air. Check passableness of maslovozvratny openings in back walls of flutes under installation of piston rings, and also oil openings in the bottom heads of rods.
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When using the compressed air do not forget to put on goggles! |
6. If walls pistons and mirrors of cylinders are not damaged and excessively are not worn-out, and the block of the engine was not pierced and not replaced, need for replacement of pistons disappears. Normal wear of pistons is shown in the form of vertical traces of development on a persistent surface and a small weak point of landing of the top kompressionny ring in the flute. Do not forget that replacement of piston rings is made without fail, regardless of their condition.
7. Attentively examine each of pistons on existence of cracks in a skirt, round ledges under installation of piston fingers and around an arrangement of rings.
8. Check persistent surfaces of a skirt of the piston on existence of scratches, the bottom – on existence of through openings and прогаров on edge. Existence of scratches on a skirt can be regarded as a sign of long overheats of the engine, or too early ignition of an air and fuel mix – check serviceability of functioning of system of cooling. Progara along the edges of the bottom are the detonation certificate. In any case, the reason of the revealed violation should be eliminated in order to avoid recurrence. As the possible reasons of formation of the listed defects leakages of soaked-up air, the wrong configuration of an air and fuel mix, violation of installation of a corner of an advancing of ignition, the wrong functioning of systems of ignition and EGR can act also.
9. Dot corrosion of pistons in the form of cavities speaks about hit in chambers of combustion and/or a case of the engine of cooling liquid. Besides, take care, that the reason of internal leaks was eliminated.
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10. Estimate size of a lateral gap of landing of piston rings in the flutes for what enclose a new ring outside in the flute on the piston and shchupy lezviyny type measure a remaining gap (see an accompanying illustration). Repeat measurement in two-three points on flute perimeter. Watch, that not перепутСпецификацать kompressionny rings (the top differs from the second). If the size of a gap exceeds admissible value (see. Specifications), pistons are subject to replacement. |
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11. Define a landing gap of pistons in the cylinders, for what an izmerye diameters of the last (see. Check of a condition of the block of the engine) also subtract from them diameters of the corresponding pistons. Measurement of diameter of the piston is made on its skirt, at an angle 90 ° (see an accompanying illustration) to an axis of a piston finger. |
12. If the landing gap of the piston in the cylinder exceeds admissible value (see.), the block it is necessary to give specifications to a pro-point with a selection of new pistons of repair diameter.
13. Estimate correctness of landing of pistons on rods, having tried повращать components in opposite directions. Existence of any appreciable люфта speaks about excessive wear of a joint. For situation correction it is necessary to deliver shatunno-piston assemblies in a car-care center workshop where necessary regenerative repair and replacement of fingers will be made.
14. Performance of procedure of removal of pistons from rods (in case of such need) also should be entrusted to specialists of car-care center. In parallel rods can be checked on existence of signs of a bend, twisting and other deformations with use of the special diagnostic equipment.
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Needlessly it is not necessary to remove pistons from rods. |
15. Check rods on existence of cracks and other mechanical damages. Temporarily remove covers of the bottom heads, take loose leaves of old bearings, wipe beds in covers and heads and check them on existence of agnails, задиров and roughnesses. Having finished check, enclose into place old loose leaves, establish covers on the bottom heads of rods and by hand tighten fixing bolts.
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If the engine is under repair for the purpose of elimination of knock of fingers, replace shatunny assemblies. |
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