5.10.2. Дефектовка engine details

It be required to you: a portable lamp, a set flat щупов, a ruler, a calliper, нутромер, a micrometer, шабер.

After dismantling carefully wash up details kerosene, blow and dry their compressed air (especially oil channels of details).

1. Examine the block, especially attentively support of a cranked shaft. Cracks in any places of the block are not supposed.

GOOD ADVICE If there is a suspicion on presence of cracks in the block (hit of a cooling liquid in картер or oils in cooling liquid), check up tightness of the block at the special stand. Check spend in the repair shops having the corresponding equipment.

2. Examine cylinders from both parties. Scratches, teases and cracks are not supposed.

GOOD ADVICE At survey of cylinders it is recommended to shine mirrors of cylinders with a portable lamp — so defects are visible much better.

Fig. 5.11. The scheme of measurement of cylinders: And – a belt of the greatest deterioration; – a zone of measurement after растачивания and хонингования; In – a belt of the least deterioration

3. Define нутромером actual diameters of cylinders. Diameter of the cylinder measure in three belts (fig. 5.11). In each belt diameter measure in two mutually perpendicular directions (longitudinal and cross-section). In a zone over a belt And (on distance of 5 mm from a plane of a socket with a block head) cylinders practically do not wear out. On a difference of the sizes in this zone and in other belts it is possible to judge deterioration of cylinders. The nominal size of the cylinder of 76,495-76,505 mm, ovality and конусность should not exceed 0,0065 mm. If the maximum value of deterioration is more 0,15 mm or ovality exceeds the specified value, chisel cylinders till next repair size of pistons (the increased on 0,25 or 0,50 mm), having left an allowance of 0,03 mm for the diameter under хонингование. Then отхонингуйте cylinders, maintaining such diameter that at installation of the chosen repair piston the settlement backlash between it and the cylinder was 0,03 mm. Дефектовку, расточку and хонингование the block spend in the workshops having the special equipment.

4. Check up a deviation from planeness of a surface of a socket of the block with a head of the block of cylinders. Put a calliper (or a ruler) to a plane:

– In the middle of the block;

– In cross-section and longitudinal directions;

– On plane diagonals. In each position flat щупом define a backlash between a calliper and a plane. It also will be a deviation from planeness. If the deviation exceeds 0,1 mm, replace the block.

5. Clear of a deposit the piston bottom шабером (it is possible to make of an old file).

6. Clear of a flute deposit under piston rings an old ring, having inserted it into a flute lateral aspect and rolling on a flute.

7. Examine pistons, rods, covers: on them there should not be cracks.

8. Examine loose leaves: if on a working surface will find out risks, teases and отслоения an antifrictional layer, replace loose leaves new. All шатунные loose leaves are identical and interchangeable.

9. Measure diameter of pistons in a plane, a perpendicular axis of a piston finger, on distance of 19 mm from a skirt edge. Diameter of the piston of the nominal size of 76,465-76,475 mm, diameters of repair pistons are increased by 0,25 and 0,50 mm. By results of measurements define a backlash between the piston and the cylinder, if necessary pick up new pistons to cylinders. The settlement backlash between the piston and the cylinder (for new details) makes 0,03 mm. It define a measurement of cylinders and pistons and provide with installation of pistons nominal or the repair sizes. As much as possible admissible backlash (at deterioration of details) 0,15 mm. If at the engine which was in operation, the backlash exceeds 0,15 mm, it is necessary to pick up pistons of the nominal size to cylinders or to establish pistons of the repair size with расточкой and хонингованием cylinders: the backlash should be as much as possible approached to the settlement.

10. Check up flat щупом a backlash on height between flutes in the piston and rings, inserting a ring into a corresponding flute. The nominal (settlement) backlash for both компрессионных rings makes 0,020 mm. If the ring is great on height and the backlash is small, finish height of a ring to the necessary value, grinding it on an emery paper laid on a glass plate.

11. Check up flat щупом a backlash in the lock of rings, having established a ring in the cylinder on depth about 50 mm.

    

GOOD ADVICE To establish a ring without a warp, advance a ring deep into the cylinder the piston.

The backlash should make 0,3 mm for both компрессионных rings and 0,4–1,4 mm for маслосъемного rings. If a backlash insufficient, cut butt surfaces of a ring. If the backlash exceeds admissible, replace a ring.

12. All pistons of the nominal and repair sizes are made with a fine precision and do not demand preliminary sorting and selection for weight. If necessary it is possible to establish in separate cylinders the pistons which were in the use, if they in a good condition. Engine balancing in this case will not be broken.

13. Measure нутромером internal diameter Dв a rod seat in gathering with a cover.

    

THE NOTE Before measurement tighten шатунные bolts the nominal moment.

14. Measure by a calliper a thickness Т шатунных loose leaves.

15. Measure by a micrometer diameter Dн шатунных necks.

16. Calculate a backlash z between шатунными loose leaves and necks of a cranked shaft under the formula z = Dv-2T-Dn. The nominal settlement backlash makes 0,019–0,070 mm. If an actual settlement backlash less limiting, it is possible to use loose leaves which have been established again. If a backlash more limiting, replace loose leaves on these necks new (a nominal thickness).

If necks of a cranked shaft are worn out and перешлифованы till the repair size reduced by 0,25 mm, replace loose leaves repair (the increased thickness).

Necks grind besides presence of the general deterioration if on them is забоины and risks or ovality than 0,004 mm, and конусность — more make more than 0,005 mm.

PREVENTIONS At repolishing шатунных necks of a cranked shaft for the repair size on the first cheek of a cranked shaft it is necessary to put a corresponding brand, for example Ш0,25. Cranked shaft, галтели which necks are executed by a method накатки, to repolishing are not subject and at deterioration of necks should be replaced.

17. Examine the top and bottom loose leaves of radical bearings. Loose leaves of the central (third) radical bearing differ from the others большей in the width. Besides, at their lateral end faces the wide fillets playing a role of basic half rings of the persistent bearing of a cranked shaft are executed. If on a working surface of loose leaves there were risks, teases, отслоения an antifrictional layer, replace loose leaves new.

THE PREVENTION It is forbidden to spend any подгоночные operations on loose leaves.

18. Examine a cranked shaft. Cracks are not supposed. On the surfaces interfaced to working edges of epiploons, there should not be scratches, забоин, рисок. At detection them replace a shaft.

19. Measure by a micrometer external diameter Dн radical necks. An actual backlash between loose leaves of radical bearings and radical necks of a cranked shaft define by a technique stated for шатунных of loose leaves. The nominal settlement backlash makes 0,005 mm. If an actual settlement backlash less limiting, it is possible to use loose leaves which have been established again. If a backlash more limiting, replace on these necks loose leaves new (a nominal thickness).

If necks of a cranked shaft are worn out and перешлифованы till the repair size with reduction of diameter by 0,25 mm, replace loose leaves repair (the increased thickness).

Necks grind besides deterioration presence if on them is забоины and risks or ovality than 0,004 mm, and конусность — more make more than 0,005 mm, reducing diameter by 0,25 mm.

PREVENTIONS At repolishing of radical necks of a cranked shaft for the repair size on the first cheek of a cranked shaft it is necessary to put a corresponding brand, for example К0,25. Cranked shaft, галтели which necks are executed by a method накатки, to repolishing are not subject and at deterioration of necks should be replaced.

20. Check up parallelism of persistent fillets of an average radical neck: if they непараллельны, drive a cranked shaft and should be replaced.

21. Wash out channels of a cranked shaft for what fill in in radial channels gasoline, preliminary having muffled them on the one hand wooden stoppers. Sustain not less than 20 mines and wash out channels gasoline, injecting its rubber pear. Wooden заглушки remove after washing of connecting channels. If necessary repeat washing to вытекания pure gasoline.

22. Clear surfaces of piston fingers of varnish adjournment, preliminary having softened them in solvent. Examine fingers. If on them cracks, excessive deterioration in a place of contact to lugs of the piston and traces from проворачивания in the top head of a rod are found out, replace fingers.

    

THE NOTE Piston fingers and apertures in lugs of pistons are made with the big accuracy. Therefore piston fingers make in the nominal diameter 17,990–17,995 mm providing a backlash of 0,01-0,02 mm between them and apertures in lugs of the piston.

Interface of a piston finger and the piston check up, inserting finger preliminary greased with engine oil into an aperture of a lug of the piston. At an ambient temperature 20 С the finger should enter into an aperture by pressing of a thumb of a hand and not drop out of a lug in vertical position of the piston with a piston finger. It is necessary to replace a finger dropping out of a lug with another. If the finger again drops out, replace the piston with a finger.

    

GOOD ADVICE In the presence of the new complete set of spare parts do not use выпрессованные piston fingers repeatedly.