Audi 100/A6

1990-1997 of release

Repair and car operation

14.8.7. Valves

THE GENERAL DATA

It is possible to reanimate any "tired" car. But technical difficulties are thus great. Without the spare parts, any станочного park, welding and other technological support here not to manage. The main thing – factory instructions on repair (they are accessible now) speak nothing about possible alternative decisions, especially about problems of a choice among details, materials and tools which are in the today's domestic market. Such is a circle of questions which both the enthusiast-single, and mechanics of "small service" lack the information. We also want in process of possibilities to fill it.

Sooner or later any engine becomes a source of troubles: глохнет in a way, it does not wish to be started in the mornings, pulls is worse, "eats" superfluous fuel and oil. It is quite probable that the reason of its whimsical behaviour is plain: to clean the carburettor enough, to adjust ignition and to replace маслосъемные caps that all has entered into norm. But happens that traditional approaches do not help it, and at compression gaugings is found out that in one or several cylinders it below admissible, – and the question becomes serious.

Then first of all specify character of malfunction: deterioration of tsilindro-piston group, подгорание facets of valves or deterioration of cores and directing plugs. The technics of diagnosing is simple enough and described in all grants on repair of engines.

Are then defined with repair. Here only it is necessary to take to itself for a rule: from any miracle liquids to be far away. The effect basically is possible, but the usual result – superfluous expenses and efforts is reached seldom. It is better to be guided by high-grade repair procedure at once.

To find a workshop where treat engines, today it is not so difficult, and not only in big cities. But here is how there work, what its quality is organised? The life shows that at all importance of experience and qualification of employees good results without the special equipment and equipment are unattainable, and in this plan disorder of technical armament of our stations and mechanics, alas, is great. And if told above concerned basically the motorist-ekspluatatsionnika the further statement is addressed not so much to it, how many to the mechanic, after all it will be a question of technology.

In cases when results of diagnostic check specify in malfunction клапанного the mechanism, the block head should be removed. The first action after dismantle, dismantling and the general survey – an estimation of backlashes between cores of valves and their directing plugs. If they above maximum permissible values, replace valves with the new. But when this vague measure is insufficient, it is necessary to replace and plugs too.

For a small workshop such operation presents known difficulties: pig-iron plugs запрессовывают in the aluminium case with a tightness. Thus to avoid microcracks and смятий, plugs should be cooled preliminary in liquid nitrogen (temperature – 196 °), and the case to warm up to 160–170 ° With (above there can be harmful consequences). All it is difficult enough, is labour-consuming and is frequently simply non-reproducible in semihandicraft conditions. Therefore in rare workshops do not deviate the ordered conditions that directly pours out in loss of quality of landing and distortion of geometry of knot. It then correct, processing "in a place" saddles of valves a vertical drill or шарошкой, and valves long and tiresomely grind in.

But today there is also other technique, extremely profitable both on labour input, and on an investment of means which thus guarantees high-quality results. It is reached by application of the original and almost unknown tool in our practice of American company "Ньюэй" (Neway).

With its help restoration of the worn out directing plugs is made on a place, without выпрессовки! Special knifes-rollers cause plastic deformation of metal, compensating deterioration of an internal surface of the plug, simultaneously forming in it a spiral fillet which improves conditions of greasing of a core of the valve, and also serves original лабиринтным as consolidation, облегачающим a problem маслосъемным to caps.

The complete set includes five knifes and a set of development for finishing processing of the plug. It is characteristic that all operations with tool "Ньюэй" are conducted manually and not connected with an electrical supply or other energy from the outside.

Now about saddles of valves. At traditional methods of their processing directing шарошки or a vertical drill freely rotates in the valve plug. Mills of "Njuej" have a motionless axis which is densely fixed already in the restored plug self-established broad цанговым "pilot". The mill is put on an axis with a precision backlash 0,5 microns that provides the minimum admission of processing. Mills of "Njuej" at the expense of unique sharpening and the form of cutting edges form on a surface of a saddle of the valve a special microrelief of type "comb": valve and saddle extra earnings occurs quickly and effectively, and need for grinding in disappears. Their productivity is high: any facet on a valve saddle turns out for 3–4 turns of the tool.

Last stage – restoration of working facets of valves. For this operation firm "Ньюэй" offers special tool "Гизматик-2". The valve motionlessly fix in the special adaptation which, in turn, establish in a metalwork vice. Enough several rotations of a mill (axial giving обеспечивется the microlift) to receive an ideal concentric surface of the valve. We will notice that on its working surface, as well as at saddle processing, the special microrelief also is formed.

Here, actually, and all. It is necessary to wash out and grease only all details, and it is possible to collect a head.

And grinding in? We will remind once again: at work as tool "Ньюэй" in this tiresome, long and tiresome operation there is no necessity. After processing of pair "valve-saddle" interface of both details occurs on very narrow corbel, practically on a line.

It is reached small (to one degree) by a divergence of corners of processing of working surfaces of a saddle and the valve (between them it is formed so-called интерференционный a corner). In the first seconds of work of the engine the interface area increases for the account смятия superficial ledges of the created microrelief on facets, and then there is a necessary 100 percent consolidation.

At cost of a set of equipment about 400 dollars (depending on a complete set) "Njuej" can pay off in the first month of work, and at repair of engines of foreign cars to bring in the appreciable income.