Infiniti QX4 service since 1996 of release
1. Introduction
2. Maintenance instruction
3. Routine maintenance
4. Engine
4.1. Specifications
4.2. Check of kompressionny pressure in cylinders
4.3. Diagnostics of a condition of the engine with use of the vacuum gage
4.4. Removal and engine installation
4.5. Removal and installation of the inlet pipeline
4.6. Replacement of a belt of a drive of GRM
4.7. Removal, check of a condition and installation of a head of cylinders
4.8. Replacement of a forward epiploon of a cranked shaft
4.9. Removal, check of a condition and installation of components of the klapanny mechanism
4.10. Replacement of epiploons of camshafts
4.11. Replacement of a back epiploon of a cranked shaft
4.12. Removal and installation of the pallet of a case
4.13. Removal, service and installation of the oil pump
4.14. Alternative versions of schemes of regenerative repair of the engine
4.15. An order of dismantling of the engine by its preparation for major maintenance
4.16. Dismantling and check of a condition of a head of cylinders and components of the klapanny mechanism
4.17. Recommendations about service of valves
4.18. Assembly of a head of cylinders
4.19. Removal of shatunno-piston assemblies
4.20. Removal of a cranked shaft
4.21. Cleaning of the block of the engine
4.22. Check of a condition of the block of the engine
4.23. Honingovaniye of mirrors of cylinders
4.24. Check of a condition of components of shatunno-piston group
4.25. Check of a condition of a cranked shaft
4.26. Check of a condition and selection of loose leaves of radical and shatunny bearings of a cranked shaft
4.27. Engine assembly order
4.28. Installation of piston rings
4.29. Installation of a cranked shaft and check of working gaps of radical bearings
4.30. Installation of shatunno-piston assemblies and check of size of working gaps in shatunny bearings of a cranked shaft
4.31. Trial start and an engine running in after major maintenance
5. Cooling and heating systems
6. Power supply systems and managements
7. Start and charge systems
8. Transmission line
9. Brake system
10. Suspension bracket and steering
11. Body
12. Electric equipment
 












4-2-proverka-kompressionnogo-davleniya-v-cilindrakh.html

4.2. Check of kompressionny pressure in cylinders

Results of check of kompressionny pressure in cylinders allow to define the general condition of components of the top part of the engine (pistons, piston rings, valves, laying of a head of cylinders, etc.) and qualitatively to estimate degree of their wear. That is especially important, the analysis of information received as a result of check allows to narrow a range of the possible reasons of falling of a compression in cylinders, rather precisely having adhered refusal to violations of functioning of quite concrete components, whether it be piston rings, valves, their saddles or head laying.

The engine should be heated-up to normal working temperature, and the storage battery is completely charged.


 PERFORMANCE ORDER

  1. Begin with pro-cleaning of candle niches (blow them the compressed air as which source in this case the ordinary bicycle pump perfectly will approach). The main objective is prevention of hit of garbage in cylinders during performance of measurements.
  2. Turn out from the engine all spark plugs (see. Head Routine maintenance).
  3. Fix a butterfly valve in completely open situation.
  1. For pressure dumping in a power supply system switch off ignition and take from the landing nest in salon the assembly block a safety lock of the fuel pump, then start the engine and wait its spontaneous останова — for dumping of residual pressure turn the engine 2-3 more times a starter, then switch off ignition and establish into place a safety lock.
  1. Disconnect the central VV a wire from a cover of the distributor of ignition.
  1. Establish компрессометр in a candle opening of the first cylinder.
  1. When using a nozzle of clamping type track, that diameter of a rubber cone made no more than 20 mm.
  1. Turn the engine at least on seven steps and consider the measuring instrument indication. On the serviceable engine pressure should accrue quickly enough. Low pressure on the first step, being accompanied its gradual increase on the subsequent, speaks about wear of piston rings. If at a further provorachivaniye of a shaft pressure does not rise, it can be regarded as the certificate of leakages of valves or violation of tightness of laying of a head of cylinders (the probability of existence of cracks in a head is not excluded also). The congestion of deposits on working facets of plates of valves also can lead to decrease in kompressionny pressure. Write down the maximum indication компрессометра.
  2. Repeat procedure for the remained cylinders of the engine. Compare results to standard requirements (see. Specifications).
  3. At excessively low results of measurement, fill in in each of cylinders through a candle opening of a little impellent oil (two-three teaspoons) and repeat check.

If addition of oil leads to pressure increase, it speaks about wear of piston rings. If the compression does not increase, the reason of its decrease are leakages of valves or violation of tightness of laying of a head. Leakages of valves can be connected with a burn-out of their saddles, either a deformation / burn-out or mechanical damages of working facets of plates.

If pressure of compression is equally underestimated in two next cylinders, with high degree of probability it is possible to speak about violation of integrity of laying of a head within its crossing point between these cylinders. Presence of cooling liquid at impellent oil will confirm this assumption.

If pressure in one of cylinders approximately for 20 % is lower, than in other and it is accompanied by violation of stability of turns of idling, it is necessary to estimate degree of wear of a cam of a drive of the corresponding final valve on a camshaft.

Unusual overestimate of kompressionny pressure usually is a consequence of an excessive nagaroobrazovaniye in combustion chambers. In this case the head of cylinders should be removed for the purpose of carrying out a dekarbonizatsiya.

At excessively low results of measurements, and also in case of violation of uniformity of distribution of pressure between cylinders it will be useful to hold testing of the engine for leaks in the conditions of a car-care center workshop. Such check will allow to define precisely a source of leak and to estimate degree of its gravity.


Block check on leaks

During this check are defined speed of an exit from cylinders of the compressed air pumped in them and directly a place of leaks. This check is alternative to compression check. Moreover, from many points of view, it is much more effective as visually to reveal a source of leak simpler, than to comprehend results of measurement of a compression.

The equipment necessary for check on leaks, is not among public therefore performance of this check should be entrusted specialists of the service center.


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4.1. Specifications
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4.3. Diagnostics of a condition of the engine with use of the vacuum gage