Due to a violation of the integrity of the cone of a candle orThe O-ring is not able to seal the cylinder tightly. The restoration of the thread can be carried out in several ways, including without removing the cylinder head from the engine.
Maintenance of the machine inMost cases are carried out with unscrewing and tightening the threaded fasteners. If parts such as a stud, nut and bolt are damaged, they are replaced with new ones. But repair becomes more appropriate when the thread in the body element is damaged.
The details of fixing the spark plugs are not, but they have a connecting thread, which is damaged in the following cases:
- In case of dust and dirt.To prevent this, in engines with a well it will be useful to turn the spark plug a few turns before removing and remove dirt with a brush or air purge.
- Work with a candlestick that does not provide proper fixation and then leads to a skew.
- Tightening in excess of the allowable force, the exact value of which can be found in the instruction manual.
The restoration of the thread by variousmethods that have their own nuances. For each case, the most optimal one is chosen depending on the price, labor, technological equipment and design. Each type of repair implies compliance with the size tolerance and the provision of the ratio of the holes.
In order to restore the threadin the block, the rational installation of the insert of a self-tapping or spiral type, with the presence of a fixing belt, and also the opening of the hole. The insert should not touch the combustion chamber. At the end of the installation, it is calibrated with a tap to get rid of damage caused during installation.
What is cold welding
It is a way of building andUnification of metallic elements, without the influence of high temperatures. In this case, the surfaces are not welded, but are glued together. The cold welding mass begins to deform, then penetrates into the parts used for work. There is no mutual penetration of substances into each other, the appearance of interatomic bonds, but a dense bond arises. In this case, this method helps to restore the spark plug thread, recreate the lost elements and repair damage.
Work
Today can be found in stores a large list.goods of foreign and Russian production. It is worth noting two main types: plastic and liquid. The latter are composed of two components, representing the bulk used in bonding, and a hardener. Plasticine tools consist of a bar with one or more layers, which must be mixed before use. In order to carry out the restoration of internal thread cold-welding, it is desirable to purchase a two-component tool, sold in two bottles.
Requires prior degreasing of allsurfaces and anti-adhesive treatment both outside and inside, as the presence of plaque and small particles can worsen the result. Further components from two bottles on a plastic or wooden surface are mixed. The resulting mass is applied to the thread, which is screwed inward and left to dry completely. If the temperature regime is observed, thread restoration will be completed after the time specified in the instruction.
Repair with conventional welding
With the engine removed the cylinder head andthe help of welding the damaged site of a candle melts. On a milling or boring machine, the recess under the candle is machined, and the attachment surfaces are restored. A new hole is drilled at a fixed angle and a thread is cut. Crimping the head is the final stage, it is a test of tightness in a high-pressure water bath.
It is worth noting that in the field of welding toolarge heat can promote cracking. Therefore, metal fusion is used in extreme cases when it is impossible to use other methods.
Thread restoration with support flange
On a milling or boring machine is installedblock head. The torn thread is drilled and a new one is cut to use the repair insert. It is made on a lathe, most often of bronze. Inside there must be a thread with the required dimension. To perform the function of heat dissipation, the insert must be in close contact with the walls; for this, the external thread diameter is made larger than the nominal one. It is wrapped in the head after applying bakelite lacquer. The part is fixed by flaring the edge of the insert.
Manual restoration
Recovering a torn thread manually, notremoving the block head from the engine is unable to properly match the old and the new hole, which can spoil the part. It is also difficult to prevent chips from entering and firmly fasten the insert, avoiding loosening with the candle.
Spiral insert
This method is used mainly on the removedblock, but with a suitable depth of the well, the location and size, you can avoid parsing the engine. Before starting to restore the internal thread, you need to check the location of the valves and the piston to provide a place for screwing in the tool.
A candle hole is being prepared.taps of the combined type, giving the opportunity to work without a metal cutting machine. When the head is located on the engine, a plastic lubricant is placed in the recesses in order to hold the chips.
Tap during twisting in brokenthe hole for the candle is centered and cuts the thread without distortion. The support flange of the insert contributes to the non-standard arrangement of the spark plug, while this method is not suitable for heads having a conical seal due to the small diameter of the wells.
Fastened gusset insert
After the formation of the parts of the outer and innerthe thread is cut in such a way that no combination of depressions and protrusions of the profile occurs, which allows to achieve the required strength of the element. With the help of the installation device, the insert is wrapped in candle wells with great depth and is easily removed from the outside. Heat-resistant glue will help in ensuring tightness. On the two outer turns of the insert, knurling must be present for tight fixation after expansion using a special profile.
