Mazda 626

1991-1998 of release

Repair and operation of the car

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 dismantle of the engine from the car
      + 3.4.4. Capital repairs of the engine
      3.4.5. Checks of the engine
      3.4.6. Removal and installation of the engine
      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 bent 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 bent 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 bent shaft
      3.4.22. Installation of a back epiploon of a bent shaft
      3.4.23. Installation of pistons and rods
      3.4.24. Launch of the engine after repair and a running in
   + 3.5. Partition of engines (2,0 and 2,5 liters of V6)
   + 3.6. Diesel engine 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 half shafts
+ 9. Brake system
+ 10. Running gear
+ 11. Body
+ 12. Electric equipment
+ 13. Electrical circuitries
+ 14. Useful tips


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 the engine are always subject to replacement.

1. Carefully remove rings from the piston, using special adaptation.
2. At removal of rings do not damage the surface of pistons. If special adaptation is absent, then rings can be removed by means of old probes or equivalent narrow metal strips. Carefully move apart a ring, enter between a ring and the piston of a plate, remove a ring, moving it on plates.
3. Repeat operation with other rings, without assuming that the lower ring got to the flute located above. As rings are subject to obligatory replacement, it is not necessary to pay attention to their casual breakage, but the experience gained at renting of rings very much is useful at installation of new rings on the piston.
4. Scrape off 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. Do not clean off the deposit remains at all the wire brush got on the electric drill as it can lead to an erosion of soft alloy from which cast pistons.
5. By means of 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, being careful at the same time not to remove piston material. Try not to damage landing surfaces of flutes of rings. Be careful of cuts as edges of the broken ring sharp.
6. After removal of a deposit, carefully wash out surfaces of flutes of rings solvent, carefully dry. Be convinced of purity of drainage oil grooves in an installation site of an oil scraper ring.
7. If traces of considerable wear are absent and if boring of cylinders is not required, then pistons should not be changed. Normal wear is shown in the form of traces of uniform vertical development on the rubbing surface of the piston and in the form of small weakening of landing of the top compression 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 zadir on the rubbing site of a surface of a skirt of the piston, traces of a progar in the central part of the bottom of the piston, and also an obgoraniye of its wreath. 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 lubrication systems and cooling is required.
10. The burn-out in the bottom of the piston demonstrates operation of the engine with the wrong installation of the moment of ignition. The piston bottom obgoraniye reason, as a rule abnormal combustion (detonation) is. If the specified defects are found, then it is required to find their reason and to eliminate, otherwise serious breakages are possible.
11. Corrosion of the piston in the form of dredging demonstrates penetration into the combustion chamber (and also in a case) cooling liquid. Here again it is required to find their reason and to eliminate, otherwise failures of the repaired engine are possible.
12. Measure a gap between the platform of a flute of a ring and a piston ring for what insert a new ring into a flute and pass the probe between a flute and a ring. Check a gap in three-four places on length of all flute.
13. Make sure that this ring corresponds to that flute in which will be established as the sizes of different flutes differ. If the gap exceeds the set limit, then the piston should be replaced.
14. Check a gap between the piston and the cylinder, having measured the corresponding diameters. Make sure that measurements are carried out on couple 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 skirt of the piston. If the gap exceeds the set limit, then the block of cylinders is subject to boring, and pistons and rings should be replaced repair. (The gap between the piston and the cylinder can also be measured, but with a smaller accuracy, by means of the probe placed between the piston inserted into the cylinder and the cylinder).

16. Check a gap between a piston finger and a head of a rod for what it is necessary to shake the piston and a rod in opposite directions. The notable side play will indicate the raised gap and need of repair of this connection. The piston assembled with a rod should be taken to repare 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 of a side play of a piston finger, then it is necessary to hand over them in a workshop of car service. 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, then pistons should not be disconnected from rods.
18. Check existence on rods of cracks and other damages. Uncover at this stage of conrod bearings, get bearings, wipe the landing surfaces of bearings on a cover of a rod and on a rod, and check existence of cracks, scratches and zadir. After check collect a rod, having installed into place bearings, and tighten nuts by hand.

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