Check of extent of compression. BMW the 5th E28/E34 series (from 1981 to 1993 of release)
Repair of BMW E28 and series E34 from 1981 to 1993
1. Cars of the BMW brand of 5-series
2. Engine
2.1. The repair work which is carried out without extraction of the engine from the car
2.2. Procedures of major maintenance of components of the engine
2.2.1. General information
2.2.2. General information about major maintenance of the engine
2.2.3. Check of extent of compression
2.2.4. Ways of removal of the engine and precautionary measure
2.2.5. Removal and engine installation
2.2.6. Options of major maintenance of the engine
2.2.7. An order of dismantling of the engine at major maintenance
2.2.8. Dismantling of a head of cylinders
2.2.9. Cleaning and check of a condition of a head of cylinders and components
2.2.10. Service of valves
2.2.11. Assembly of a head of cylinders
2.2.12. Removal of pistons / rods
2.2.13. Removal of a cranked shaft
2.2.14. Removal and check of a condition of an intermediate shaft
2.2.15. Cleaning of the block of cylinders
2.2.16. Check of a condition of the block of cylinders
2.2.17. Honingovaniye of cylinders
2.2.18. Check of a condition of pistons / rods
2.2.19. Check of a condition of a cranked shaft
2.2.20. Check of a condition of radical and shatunny bearings
2.2.21. Engine balance of assembly at major maintenance
2.2.22. Installation of piston rings
2.2.23. Installation of an intermediate shaft
2.2.24. Installation of a cranked shaft and check of lubricant gaps of radical bearings
2.2.25. Installation of a back epiploon of a cranked shaft
2.2.26. Installation of pistons / rods in collecting and check of lubricant gaps in bearings of rods
2.2.27. Start and an engine running in after major maintenance
2.2.28. Diagnostics of malfunctions of the engine
3. Cooling system
4. Power supply system
5. Ignition system
6. Control systems of the engine and decrease in toxicity of the fulfilled gases
7. System of production of the fulfilled gases
8. Coupling
9. Manual box of gear shifting (RKPP) and automatic transmission (AT)
10. Transmission line
11. Steering and suspension bracket
12. Brake system
13. Body
14. Control body sizes
15. Heater and air conditioner
16. System of onboard electric equipment
17. Routine maintenance of the car
18. Size table and adjusting data
19. Schematic electric circuits
20. Governing bodies and operation receptions
21. System of onboard diagnostics - a principle of functioning and codes of malfunctions
 








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2.2.3. Check of extent of compression

Check of extent of compression shows, what mechanical condition of the top level of the engine (pistons, rings, valves, head laying). In particular, check can show that extent of compression is lowered because of the leak caused by wear of piston rings, defective valves and saddles or because of the burned-through laying of a head of the block.

At this check the engine should be heated-up to normal working temperature, and the storage battery - completely


 PERFORMANCE ORDER

  1. Before removal of spark plugs clear area round them (it is necessary to apply if it is available, the compressed air, differently it is possible to use the bicycle pump or a small brush). The purpose consists in that at check not to allow hit in dirt cylinders.
  2. Remove from the engine all spark plugs (look Head Routine maintenance of the car).
  3. Block a butterfly valve in completely open situation or let the assistant holds a pedal in the pressed situation.
  1. On carburetor models disconnect from the ignition coil a wire of a low voltage. On models with injection of fuel disconnect the fuel pump and an ignition chain, having removed the main relay (it is specified by an arrow).
  1. It is necessary for prevention of ignition of fuel which could be injected into an impellent compartment. Usually main relay is located under a cowl near the panel of safety locks, however for exact definition of an arrangement on your model address to Head System of onboard electric equipment.
  2. Establish in a candle No. 1 opening компрессометр (the cylinder No. 1 is located from a radiator).
  3. Starter turn the engine, at least, on seven steps of compression and watch compressor indications. On the serviceable engine extent of compression will quickly increase. Low extent of compression in the first step with gradual increase in the subsequent steps testifies to wear of piston rings. Low extent of compression in the first step, not increasing in the subsequent steps, indicates leaks in valves or on прогар laying of a head of cylinders (the crack in a head of cylinders also can be to it the reason). The deposit on internal surfaces of heads of valves also can cause low extent of compression. Write down the greatest measured value.
  4. Repeat operation for other cylinders and compare results to values of extent of compression in the Size table and adjusting data at the end of the Management.
  5. If extent of compression low, fill in through openings for spark plugs in each cylinder a small amount of impellent oil (having pressed, about, three times a butterdish of plunzherny type) and repeat check.
  6. If after oil addition extent of compression increased, piston rings are definitely worn-out. If extent of compression considerably did not increase, in valves or through laying of a head of cylinders there is a leak. Leak in valves can be caused by an obgoraniye of saddles of valves and/or facets, and also a curvature of valves and existence of cracks and dents.
  7. If two next cylinders have equally low extent of compression, it is quite probable that laying of a head of cylinders between them burned through. Cooler existence in chambers of combustion or a case will confirm this offer.
  8. If extent of compression in one of cylinders for 20 % is lower, than in the others, and the engine idling works slightly roughly; that the final cam of a camshaft is probably worn-out.
  9. If extent of compression is unusually high, combustion chambers, possibly, are covered with a deposit.
  10. In this case it is necessary to remove a head of cylinders and to remove a deposit.
  11. If extent of compression is lower than norm or strongly differs between cylinders, it is useful to carry out diagnostics of leaks in a repair truck. This check will precisely indicate the reason of leaks and its degree.


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2.2.2. General information about major maintenance of the engine
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2.2.4. Ways of removal of the engine and precautionary measure