Troubleshooting and repair of cylinder head and its parts

If the cylinder head is disassembled, it is necessary to decide whether it is appropriate repairs. To do this, hold Troubleshooting head. Especially characteristic feature of burn cylinder head gasket is, for example, the deformation of the surface. Also, cracks may be formed between the valve seats or the threads of spark plugs. Typically, the head of the block should not be replaced, if the size of the cracks is not more than 0.5 mm or if the crack is only in the first thread.

Valve springs

Troubleshooting for valve springs, use the recommended instructions tester springs. If not, then we must do the following:

- Used to compare with the new spring. To do this, hold both spring and slowly clamping vise. If both of the spring will be equally compressed, that is a sure sign that they have approximately the same elasticity;

- If it turns out that the old spring in compression becomes significantly shorter than the new, this is evidence of fatigue, so the spring should be replaced in the kit;

- Spring set in a row on a smooth surface (glass) so that the coil was closed on the underside. Put next to a spring steel square. Measure the clearance between the spring and square at the upper side (Fig. 36) - it should not exceed 2.0 mm. Otherwise, the spring is deformed and must be replaced.

Sleeve valves

Control valve guides should be carried out as follows:

- Clean the valve guides, it is necessary to passing the sleeves back and forth in the gasoline-soaked rags. In need of thorough cleaning and valve stems, and then lubricated valves are installed alternately in their holes;

- Set on the upper side of the cylinder head with the corresponding dial gauge holder (Fig. 37) and squeeze the valve from the channel until the end of the valve stem is flush with valve guide on the other side of the cylinder head;

- To move the valve plate on the upper side in different directions, and readout of a dial indicator. If they comprise more than 1.0 mm for the intake valves and 1.3 mm - at the outlet, the valve sleeve must be replaced;

- As already mentioned, the general condition of the cylinder head check before replacing the valve plugs.

Defects are allowed, as specified above in the form of small cracks between the valve seats (Fig. 38) or between the valve seat and the first coil in the spark plug hole threaded part provided that the width of the cracks is not more than 0.5 mm. With additional polishing of the cylinder head and the size indicated in Fig. 39, must not be less than 135.6 mm;

- Pulling out the valve sleeve before it must first check. If the sleeve 5 (see. Fig. 35) is a protrusion, the spew is carried by the combustion chamber when this projection is not formed, it is extruded from the die by the camshaft. Old sleeve is extruded appropriate mandrel. In order to facilitate the work of the cylinder head can be heated to 100 ?� C. It is used for removing the mandrel must be screwed finger suitable diameter for mounting inside the sleeve;

- When replacing the valve guides are treated and the valves themselves (see. Div recommendations. "Saddle valves"). In this case, must be carried out rounding the valve seats;

- Lubricate the new valve guides and drive them into the cold cylinder head from the camshaft. Thereafter, the pressure compacts longer increase, since otherwise it will shear rib;

- After pressing in valve guides should be treated with a special Scan 3120 (Fig. 40). In her absence, you can use an adjustable scan. Bushings intake and exhaust valves to deploy up to 7.0 mm. The required operating clearance of bushings valve is installed automatically.

Valve seats

If the camshaft bearings are worn, replace the cylinder head. In this case, no work on the valve seats of the new head does not need to spend.

It should be visually check all seat valves for wear or corrosion. Slight wear can be eliminated corner cutter (45 ?�). The angles depend on the engine. For engine AEV (1,0 l) angles are shown in Fig. 41 and 42.

The other engines, including engines, production of which began in 1996, the angles of the intake and exhaust valves are the same. Kind of seats in section shown in Fig. 43. The diameter of the valve seat and has different values depending on the engine model. If the seat shall be subjected to additional processing, it is necessary to adhere to the table of sizes. Keep in mind that the sample of metal in the cylinder head for the seats should not be too deep.

To determine the amount of additional processing valve seats necessary to carry out the following measurements:

- Install the valve into the sleeve and press it tightly against the valve seat;

- Measure the distance a (Fig. 44) between the top of the valve and the upper edge of the cylinder head;

- Define the maximum size of additional milling of the measured and minimum allowable value; for intake valves it is 35.8 mm for the exhaust valves - 36.1 mm. These dimensions are set for all engines. Subtracting the minimum value of the measured distance, we obtain the maximum size of b (see. Fig. 41-43).

Sequence of operations in milling should be as follows.

Engine displacement of 1.0 liters (AEV):

- Milling angle of 30 ?� from the intake valves 45 or exhaust valves have ?� and then treated slightly from the upper edge of the intake valves corner cutter 45 ?� or 60 ?� - the bottom edge of the seat to reduce the width of the saddle to 2.0 mm. In the exhaust valves corner cutter 30 ?� processed only the upper side of the valve seat. Milling ends as soon as the size of the seat corresponds to the specified width.

Engine capacity of 1.3; 1.4 and 1.6 liters:

- Milled angle of 45 ?� at the inlet and outlet valves, and then a little treat at the seats of both valves corner cutter 45 ?� upper edge or the corner cutter 60 ?� bottom edge to reduce the width of the saddle and bringing it to 2.0 mm.Posle milling must be checked and (or) the following:

- If the result of the measurement (see. Fig. 44) found that the size of at the intake valve is 36.5 mm (as compared with a minimum distance of 35.8 mm), this means that there is still margin depth equal to 0, 7 mm in order to recover the corresponding valve seat;

- If the valve seat "clean up" is not possible, consult the SRT. You can order the installation of rings for the valve seats, in this case, will also be installed and new valves;

- Additional processing to grind past the valve seats. For this purpose, the valve seat surface grease a small amount of lapping paste and the valve to the corresponding saddle. Install the suction cup on the valve and turn it in one direction and then the other (Fig. 45);

- Thoroughly cleaned after grinding all parts of dirt and lapping compound. Check the valve seat for the plate and the ring. Both items should be visible solid frosted ring that indicates the width of the valve seat;

- Put a pencil on the circumference of the saddle a few strokes at 1 mm apart. Then gently lower the valve on the seat and turn it 90 ?�, it must perform when you click on the valve;

- Again to remove the valve and check for any remaining pencil strokes applied. If the width of the valve seat is within these values, the head can be set again. Otherwise, additional processing or valve seats (worst case) to replace the head.

Valves

Minor damage to the surface of the valve plates can be removed by lapping valve for installation in a bore of the cylinder head as described above. Additional grinding valves on the machine is prohibited.

Remove the valve sizes as shown in Fig. 46 and replace all the valves that do not match these sizes. It is necessary to take into account differences between the intake and exhaust valves. The width of the valve seat as well (Fig. 47) and the thickness of the edge b of the valve must conform to the specified values. None of the valve size should not be less than 0.5 mm.

If the ends of the valve stems are worn, the surface of the rod can be abraded on the machine, removing the metal layer is not more than 0.50 mm.

Cylinder Head

It should thoroughly clean the gasket surfaces of the cylinder head and cylinder block and check the surface of the cylinder head on the deformation. Set this measuring line on it, as shown in Fig. 48 and determine the probe via the gap in the longitudinal, transversal and diagonal directions between the cylinder block and cylinder head. If the gap passes the plate gauge thickness greater than 0.10 mm, the head should be abraded. If the gap in some place more significantly, the head should be replaced.

Surface grinding head can be carried out as long as it is maintained Minimum height of 135.60 mm. The height of the line measured, as shown in Fig. 39. If the height of the cylinder head is less than this value, the head needs to be replaced.

Camshaft

The camshaft of each type of engine has a corresponding designation. When replacing the camshaft should definitely take into account the type of engine.

For identification of the camshaft between the cam and the intake valve cam of the exhaust valve of the first cylinder in the place indicated by the arrow in Fig. 49, embossed marking. In addition, to respond adequately to the marking belt, which may have one of the forms specified in Figure 1-4.

ADX Engine

In the place of the arrow, embossed symbol 030 030 AS or AN. Girdle has a view corresponding to 1 and 2 or 1 and 4.

Engine AEA

In place of the arrow, embossed symbol 032 N or 032 P. girdle has a view corresponding to 1 or 1 and 3.

Engine AEV

In the place of the arrow, embossed symbol 030 VA. No girdle.

Engine Aex

In the place of the arrow, embossed symbol 030 AM. No girdle.

Install the camshaft with two tails end bearings in a prism clamp lathe centers, as shown in Fig. 50, and set the dial gauge on the neck of the average bearing. Slowly rotate the camshaft and read indicator. If the reading exceeds 0.01 mm, the shaft is deformed and must be replaced.

Check neck bearings for defects.

For checking the clearance in the bearings of the camshaft is necessary to use strips of polymeric material Plastigage. Verification carried out without pushers. Control is carried out as follows:

- Thoroughly clean the bearing hole in the cylinder head and the bearing caps and insert them into the shaft. Several times to crank it;

- Put a small strip of polymeric material Plastigage transversely on the upper side of each crankshaft bearing and install the bearing cap in accordance with their numbering and the location (see. Fig. 32);

- Tighten the nuts evenly covers, ranging from the center to the moment of 6 Nm (use for this torque wrench with small scale division), and after reaching the limit tighten each nut yet another 1/4 turn (90 ?�) . After that, the shaft is no longer rotate;

- Again turn the cover and disconnect using is in complete Plastigage gauge to measure the width of the flattened strip. If it is determined that the width exceeds 0.10 mm, it means that the limit value of wear of the bearing and the shaft (in most cases and cylinder head) must be replaced. To measure the endplay camshaft install it in the cylinder head (without pushers) and fixed with the lid of the central bearing. Put the cylinder head on a smooth surface. Set at the end of the camshaft dial gauge (Fig. 51) and move the shaft in one direction and then the other side. The backlash should not exceed 0.15 mm. Otherwise the surface of the bearing cap is worn.