Mazda 626

1991-1998 of release

Repair and car operation

Mazda 626

+ 1. Maintenance instruction
+ 2. Maintenance
- 3. Engines
   + 3.1. Petrol engines (1,6 and 1,8 liters)
   + 3.2. Petrol 4-cylinder engine (2 liters)
   + 3.3. Petrol V6 engine (2,5 liters)
   - 3.4. Partition of engines (1,6 and 1,8 liters)
      3.4.1. Introduction
      3.4.2. Technical characteristics
      3.4.3. Repair work without engine dismantle from the car
      + 3.4.4. Major maintenance of the engine
      3.4.5. Engine checks
      3.4.6. Removal and engine installation
      3.4.7. Preparation for a partition
      3.4.8. Engine partition
      3.4.9. Partition and check of a head of cylinders
      3.4.10. Repair of valves
      3.4.11. Assembly of a head of cylinders
      3.4.12. Removal of pistons and rods
      3.4.13. Removal of a cranked shaft
      3.4.14. Check and cleaning of the block of cylinders
      3.4.15. Honingovaniye of cylinders
      3.4.16. Check of pistons and rods
      3.4.17. Check of a cranked shaft
      3.4.18. Check of radical bearings and bearings of rods
      3.4.19. Engine assembly order
      3.4.20. Installation of piston rings
      3.4.21. Installation of a cranked shaft
      3.4.22. Installation of a back epiploon of a cranked shaft
      3.4.23. Installation of pistons and rods
      3.4.24. Engine start-up after repair and a running in
   + 3.5. Partition of engines (2,0 and 2,5 liters of V6)
   + 3.6. Diesel engine of 2,0 liters
   + 3.7. Systems of electric equipment of the engine
+ 4. Heating and ventilation
+ 5. Fuel system
+ 6. Exhaust system
+ 7. Transmissions
+ 8. Coupling and semi-axes
+ 9. Brake system
+ 10. Running gear
+ 11. Body
+ 12. Electric equipment
+ 13. Electroschemes
+ 14. Good advice

3.4.16. Check of pistons and rods


Before check rods and pistons it is necessary to clear and remove old rings from the piston.


Old piston rings when dismantling engine always are subject to replacement.

1. Carefully remove rings from the piston, using the special adaptation.
2. At removal of rings do not damage a surface of pistons. If the special adaptation is absent, rings can be removed by means of old щупов or equivalent narrow metal strips. Carefully move apart a ring, enter between a ring and the plate piston, remove a ring, moving it on plates.
3. Repeat operation with other rings, without allowing, that the bottom ring got to the flute located above. As rings are subject to obligatory replacement, by their casual breakage it is not necessary to pay attention, but the experience acquired at съеме of rings, very much is useful at installation of new rings on the piston.
4. To Soskrebita a deposit from the bottom of pistons. After removal of the top rough layer of a deposit, clean the piston bottom a brush or an emery paper on a basis made of cloth. By no means, do not clean off the deposit remains the wire brush got on an electrodrill as it can lead to an erosion of a soft alloy from which pistons are cast.
5. By means of the special adaptation remove a deposit from flutes of piston rings. If such adaptation is absent, it is possible to use the old broken piston ring. Delete only a deposit, observing thus care not to remove a piston material. Try not to damage landing surfaces of flutes of rings. Be careful of cuts, as edge of the broken ring sharp.
6. After deposit removal, carefully wash out surfaces of flutes of rings solvent, carefully dry. Be convinced of purity of drainage oil grooves in an installation site of a maslosjemny ring.
7. If traces of considerable wear are absent and if boring of cylinders is not required, pistons should not be changed. Normal wear is shown in the form of traces of uniform vertical development on a rubbing surface of the piston and in the form of small weakening of landing of the top kompressionny ring. Replacement of piston rings is obligatory.
8. Carefully check existence of cracks on a piston skirt, on lugs of a piston finger and on airfields of piston rings.
9. Check existence of chips and задиров on a rubbing site of a surface of a skirt of the piston, traces прогара in the central part of the bottom of the piston, and also an obgoraniye of its wreath. If chips and teases are observed, it indicates a frequent overheat of the engine, abnormal combustion of a fuel mix can be one of which reasons. In this case careful check of systems of greasing and cooling is required.
10. The burn-out in the bottom of the piston testifies to operation of the engine with the wrong installation of the moment of ignition. The reason of an obgoraniye of the bottom of the piston, abnormal combustion (detonation) as a rule is. If the specified defects are found, it is required to find their reason and to eliminate, serious breakages otherwise are possible.
11. Piston corrosion in the form of dredging testifies to penetration into the combustion chamber (and also in a case) cooling liquid. Here again it is required to find their reason and to eliminate, failures of the repaired engine otherwise are possible.
12. Measure a gap between a platform of a flute of a ring and a piston ring for what insert into a flute a new ring and pass щуп between a flute and a ring. Check a gap in three-four places on length of all flute.
13. Be convinced that this ring corresponds to that flute in which it will be established as the sizes of different flutes differ. If the gap exceeds the established limit, it is necessary to replace the piston.
14. Check a gap between the piston and the cylinder, having measured the corresponding diameters. Be convinced that measurements are carried out on pair of interfaced details.
15. Measure diameter of the piston on a skirt. The size of a gap is defined as a difference of diameters of the cylinder and a piston skirt. If the gap exceeds the established limit, the block of cylinders is subject to boring, and it is necessary to replace pistons and rings repair. (A gap between the piston and the cylinder it is possible to measure also, but with smaller accuracy, with the help щупа, placed between the piston inserted into the cylinder, and the cylinder).

16. Check a gap between a piston finger and a rod head for what it is necessary to shake the piston and a rod in opposite directions. Notable люфт will point to the raised gap and need of repair of this connection. Assembled with a rod it is necessary to hand over the piston in repair for replacement of piston fingers, and also for boring of a head of a rod and an opening in the piston under the repair sizes.
17. If it is necessary to remove pistons from rods for replacement of pistons, or for elimination люфта a piston finger, it is necessary to hand over them in a car-care center workshop. At the same time it will be necessary to check a bend and twisting of rods for what in workshops there is a necessary equipment. If installation of new pistons or rods is required, pistons to disconnect from rods does not follow.
18. Check existence on rods of cracks and other damages. Remove at this stage of a cover of shatunny bearings, get bearings, wipe landing surfaces of bearings on a cover of a rod and on a rod, and check existence of cracks, scratches and задиров. After check collect a rod, having established into place bearings, and tighten nuts by hand.