- By means of the special adaptation remove rings from pistons — try not to damage walls of the last casually.
- 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.
|
|
At all do not use for cleaning made of a soft material and pistons easily subject to an erosion wire nozzles to an electrodrill! |
|
-
By means of the special adaptation clean flutes under installation of rings on pistons.
|
|
It is alternatively possible to use for this purpose a fragment of an old piston ring, however be careful — do not scratch a bottom and walls of a flute and do not cut fingers.
|
|
- 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.
|
|
When using the compressed air do not forget to put on goggles! |
- If walls of pistons and a mirror 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 also 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.
- 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.
- Check persistent surfaces of a skirt of the piston on existence of scratches, the bottom — on existence of through openings and прогаров on edge. Presence 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.
- 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.
|
-
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. Repeat measurement in two-three points on flute perimeter. Watch to mixing kompressionny rings (the top differs from the second). If the size of a gap exceeds admissible value (see. Specifications), pistons are subject to replacement.
|
|
-
Define a landing gap of pistons in the cylinders for what measure 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 a persistent surface at an angle 90 ° to an axis of a piston finger and on the set removal from a skirt cut.
|
|
|
|
On engines considered in the real Management selective landing of pistons in cylinders is provided. Thus cylinders and pistons are as appropriate marked. |
|
A.
B.
|
- 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.
- Estimate correctness of landing of pistons on rods, having tried повращать components in opposite directions. Existence a little appreciable люфта speaks about excessive wear of a joint.
|
-
Mark pistons on compliance to the cylinders — numbers of cylinders fabrichno are put on rods and covers of shatunny bearings.
|
|
-
Remove a lock ring of fixing of the piston on a rod.
|
-
Warm up pistons in an oil bath to temperature 60 — 70°С, then squeeze out of the top heads of rods piston fingers.
|
|
|
|
Alternatively pistons can be removed at room temperature with application of a special press. |
|
- Check rods on existence of signs of deformations. Compare results of measurements to requirements of Specifications, in case of need make replacement.
|
A.
B.
|
- For the purpose of definition of landing gaps measure diameter of a piston finger and openings under its landing in the top head of a rod and in the piston.
|
A.
B.
|
- Compare results of the corresponding calculations to requirements
of Specifications, excessively worn-out components replace — when squeezing from a rod of the top plug use a suitable opravka, when landing track correctness of combination of oil openings.
|
|
- At assembly the new lock ring is established on the piston by the equipped facet the party (if the facet in general is provided) from the piston. Having planted a ring warm up the piston in an oil bath, plant on a rod (track correctness of orientation of components on labels) and press a finger (the rod should appear precisely in the middle).
|
|
- Plant the second lock ring (also new) and check freedom of rotation of the piston on a finger.
|
- At installation of piston assemblies track, that pistons were developed by forward labels on the bottoms forward on the engine. Do not forget that number marking on covers of shatunny bearings and the bottom heads of rods should settle down on the one hand assemblies.
|
|
- Evenly tighten bolts of covers of bearings with demanded effort and check size axial люфта rods on pins of a cranked shaft. Compare results of measurements to demanded effort, in case of need replace the corresponding rods and/or a cranked shaft.
|
