4.2. Check of compression pressure in cylinders
Results of check of compression 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 to qualitatively estimate degree of their wear. What is especially important, the analysis of information obtained as a result of check allows to narrow a range of the possible reasons of falling of a compression in cylinders, having rather precisely tied refusal to violations of functioning of quite concrete components, whether it be piston rings, valves, their saddles or laying of a head.
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The engine has to be heated-up up to the normal working temperature, and the rechargeable battery is completely charged. |
PERFORMANCE ORDER |
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If addition of oil leads to increase in pressure, it speaks about wear of piston rings. If the compression does not increase, leakages of valves or violation of tightness of laying of a head are the reason of its decrease. 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, then 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 motive oil will confirm this assumption.
If pressure in one of cylinders is about 20% lower, than in other and it is followed by violation of stability of turns of idling, it is necessary to estimate degree of wear of a cam of the drive of the corresponding final valve on the camshaft.
Unusual overestimate of compression pressure usually is a consequence of an excessive nagaroobrazovaniye in combustion chambers. In this case the head of cylinders has to be removed for the purpose of carrying out decarbonization.
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 workshop of car service. Such check will allow to define precisely a source of leak and to estimate degree of its gravity.
Check of the block on leaks
During this check are defined exit speed from cylinders of the compressed air pumped in them and directly the place of leaks. This check is an alternative to check of a compression. Moreover, from many points of view, it is much more effective as visually it is simpler to reveal a leak source, 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.