65637bd9 Check

Correct mutual orientation of the piston and rod

1. Number of dimensional group of the piston

2. Orientation tag

3. A lubricant opening in a rod body

4. The place of drawing number of the cylinder to which the rod belongs


1. Before check rods and pistons it is necessary to clear and remove old rings from the piston.
2. Carefully move apart a ring, having displaced on the top part of the piston. That at removal the ring did not get to an empty flute, lay two-three old probes under a ring.
3. Scrape off a deposit from the bottoms of pistons. After removal of the top rough layer of a deposit clean the piston bottom a wire brush manually (or an emery paper on a basis made of cloth).
4. Carefully remove a deposit from flutes of pistons by means of the old broken piston ring.
5. Wash out the piston assembled with a rod in solvent, carefully dry. Be convinced of purity of grooves for an oil drain in flutes under piston rings.
6. Measure by a micrometer diameter of the piston perpendicular to an axis of a piston finger (at the set distance from edge of a skirt of the piston) and compare result to standard. The dimensional group of the piston is stamped on its bottom. If wear of the piston exceeds maximum permissible, then the piston is subject to replacement.
7. Check a gap between a piston ring and a wall of a flute of the piston. For this purpose insert a ring from the outer side into the corresponding flute and measure by the probe a gap between the top surface of a ring and a wall of a flute. Even if at a new ring the gap exceeds norm, replace the piston.
8. Check a gap in a joint of piston rings for what insert a ring into the corresponding cylinder and push the piston bottom to exclude a ring distortion at measurement. Push a ring on such depth at which the edge of a skirt of the piston will be made even to the demountable plane of the block of cylinders then get the piston. Measure a gap by the probe. If the gap exceeds norm, then replace rings and repeat the procedure. If the gap exceeds norm with new rings, then the cylinder should be chiseled and otkhonningovat (cm. subsection
9. Carefully check existence of cracks on a piston skirt, on lugs of a piston finger and in places between flutes of piston rings.
10. Check existence of chips and zadir on the rubbing site of a skirt of the piston, obgoraniye traces at the edges of the bottom. If chips and teases are observed, then it indicates a frequent overheat of the engine, one of the reasons of which can be an abnormal combustion of fuel mix. In this case careful check of power supply systems, lubricants and coolings is required. Oplavleniye traces on the side surface of the piston demonstrate break of gases from the combustion chamber. The burn-out of the bottom of the piston or the burned sites at the edges of the bottom indicate abnormal operation of the engine because of the wrong installation of the moment of ignition (too early ignition), or owing to a detonation. If the specified defects are found, then it is necessary to find their reason and to eliminate, otherwise manifestation of the reasons of such wear perhaps and further. An air suction on the soaking-up collector, the wrong installation of the moment of ignition, failure of the system of injection of fuel can be the reasons of abnormal operation of the engine.
11. Corrosion of the piston in the form of small poles (pitting) demonstrates penetration into the combustion chamber (and also in a crankshaft case) cooling liquid. Here again it is required to find the reason and to eliminate.
12. Carefully check existence of such damages on rods as cracks on heads about piston fingers and in installation sites of conrod bearings. Check whether there is a deformation of a body of a rod (twisting or a bend). Damage of rods is improbable and is shown only in cases of jamming of the engine or a strong overheat. Careful check of rods can be executed only in a workshop where there is a necessary equipment.
13. If necessary the piston can be removed from a rod and to collect with a rod as follows.
14. Get lock rings of a piston finger and push out piston Pale. If necessary rest the piston and carefully beat out a finger blows молоткапо to a mandrel.
15. Extraction of a piston finger is considerably facilitated if to heat the piston to 60–70 °C.
16. Check existence on a piston finger and an opening in a head of a rod of signs of wear or damages. Check a finger gap in the piston and in a rod.
17. If the plug of a head of a rod and a piston finger are strongly worn-out or if the finger gap in a head of a rod exceeds norm, then the finger and the plug should be replaced. Replacement of plugs of heads of rods should be carried out in a workshop.
18. If the gap between the piston and a finger considerably exceeds norm, then the piston and a finger should be replaced in a set. Keep in mind that the gap between the piston and a finger does not play so essential role as a gap in a rod head.
19. Rods do not demand replacements in itself, except for cases of jamming of the engine, or other serious breakages. Check a condition of rods survey, at detection of deformation of rods hand over them in a workshop of car service for check and repair.
20. Get new details on replacement with worn-out.
21. Orient the piston and a rod so that the tag on a part of the piston which has to be turned towards a forward part of the engine (in the form of an arrow or line) correctly settled down rather lubricant opening in a rod body (see rice. Correct mutual orientation of the piston and rod). At the correct mutual orientation the tag on the piston has to be turned towards a forward part of the engine, and the lubricant opening in a body of a rod has to be turned towards a back part of the block of cylinders.
22. Slightly oil a piston finger fresh for the engine and insert into openings in the piston and in a rod head. If necessary besiege a finger into place easy blows of the hammer to a mandrel.


To facilitate installation of a piston finger the piston is recommended to be heated.

23. Check freedom of rotation of a finger in piston lugs, then establish lock rings in piston flutes.