Citroen Xantia

1. Scratch out from interfaced surfaces of a head of cylinders all traces of a material of an old lining. Be cautious, try not to damage components.
2. Scratch out coal adjournment from walls of chambers of combustion, and also inlet and final ports of a head. Carefully wash out a head kerosene or other suitable solvent.
3. Scratch out from surfaces of valves the basic layer of coal adjournment, then manually smooth out plates and cores of valves a wire brush.

1. Attentively check up a head of cylinders on presence of cracks, traces of leaks of a cooling liquid and other damages. The tresnutaja head is subject to replacement without fail. In case of absence of confidence of definition of a condition of a head, it is necessary to address for corresponding consultations in a car-care centre workshop.
2. By means of a planeness measuring instrument (the steel ruler put on an edge) and probeа лезвийного type check up an interfaced surface of a head on presence of signs of deformation. If неплоскостность exceeds admissible value (Specifications see), it is necessary to give a head in проточку to a mechanical workshop, or to replace it (in case мехобработка will lead to reduction of height of a head below an admissible limit).

On diesel engines if at мехобработке from a head acts in film more than 0.1 mm of height, it will be necessary to pierce also chambers of combustion and a saddle of valves for the purpose of preservation of correct dimensional parities at landing of plates of valves and directing plugs.

3. Check up a condition of saddles of valves in each of combustion chambers. In case of revealing of cavities, cracks or traces прогара, it is necessary to subject a head to the special regenerative repair which performance lies out of limits of qualification of the average mechanic-fan and it should be entrusted to experts of car-care centre. If only insignificant defects are revealed, they can be eliminated in the course of performance of grinding in of valves (see more low).
4. In case of deterioration of the directing plugs which characteristic sign is excessive lateral люфт the valves, accompanied by a dense dark blue smoke on an exhaust at work of the engine, the plug are subject to replacement. Measure diameters of cores of the cylinders of valves removed from a head (see more low), and also internal diameters of directing plugs. By subtraction of results of the first measurements from corresponding results of the second the backlash of landing of valves in plugs is defined. Compare results of calculations to requirements of Specifications. If the size of landing backlashes falls outside the limits an admissible range, it is necessary to make replacement of valves / their directing plugs. Performance of replacement of plugs will charge more correctly to experts of car-care centre, at whose order there are all necessary tools.
5. Restoration of saddles of valves is made only after replacement of directing plugs.

6. On diesel engines check up vortical chambers on presence прогаров, cracks and other this sort of damages. Presence of small threadlike cracks in walls of chambers is admissible. Replacement of chambers is made only in cases serious прогаров, deformations or landing easing in a head and should be charged experts of a workshop of car-care centre. With the help циферблатного a measuring instrument плунжерного type measure height выступания vortical chambers. Null a measuring instrument, having rested плунжер in прокладочную a head surface, then translate it on a chamber end face. Compare results of measurements to requirements of Specifications. If the height выступания vortical chambers exceeds admissible value, it is necessary to address for council to experts of the service-centre of company Citroyon.

1. Check up plates of valves on presence of cracks, cavities and traces прогара. Estimate degree of operation of cores of valves. Check up, whether there are no cracks in necks of cores. By rotation check up valves on a bend of cores. Make sure of absence of cavities and signs of excessive deterioration of end faces of cores. Revealing of any of the listed defects demands replacement of valves.

2. If during carrying out described above check the condition of valves is recognised by satisfactory, measure a micrometer diameters of their cores in several points. Any appreciable difference in results made for each of valves of measurements specifies in deterioration of its core and necessity of carrying out of replacement.

3. Recognised suitable for the further use valves should be ground in to the saddles for a guarantee of tightness of closing of chambers of combustion. If defects of a surface of saddles are only insignificant, they can be eliminated in the course of performance of such grinding in. Necessary smoothness of polishing of a surface grew grey after their regenerative проточки can be reached only at use special притирочных pastes. In case of revealing of deep defects or прогаров saddles the condition of a head of cylinders and valves should be checked up the expert who then makes the decision on volume of a recovery work or even replacement of valves or their saddles.
4. For grinding in performance establish a head upside down on a strong workbench.

5. Put a little притирочной pastes of demanded granularity on a surface of a saddle of the valve, then fix a sucker special притирочного adaptations on an external surface of a plate of the valve. Reciprocating rotary motions of the adaptation start to grind in the valve to the saddle, from time to time, raising it for the purpose of paste redistribution. Placing under a plate of the valve of a weak spring will help to facilitate procedure performance essentially.

6. At use coarse-grained притирочной paste try to achieve dim matte colouring of ground in surfaces of the valve and its saddle. Having received satisfactory result, wipe surfaces and repeat procedure with application of more fine-grained paste. It is possible to consider grinding in finished when on working surfaces of a saddle and a valve plate there are smooth equal continuous rings of matte light grey colour. It is not necessary to continue grinding in longer, than it is really necessary in order to avoid excessive understating of a working surface of a saddle.
7. Having finished grinding in of all valves, remove pure rags all traces of paste. Before assemblage wipe surfaces kerosene.

1. Check up клапанные springs on presence of mechanical damages and overheat traces (colouring change). Whenever possible compare free length of the removed springs to length of the new.
2. Establishing each of springs vertically on a flat surface, check up their severity торцовки. Springs with infringement торцовки, it is equal as weakened and given, are subject to replacement. Replacement of springs is usually made in the complete set and, whenever possible, without fail.
3. Replacement маслоотражательных caps of cores of valves is made also without fail, without dependence from their condition.