Repair of the cylinder head

Disassembly of the cylinder head is executed in the following sequence:

- Remove the cylinder head

(see. Sect. 3.1.6);

- Unscrew the intake manifold and the exhaust nuts, remove the collectors;

- Remove the camshaft (camshafts) and hydraulic tappets (see. Sect. 3.1.5);

- Compress the valve spring and special tool remove crackers of the valve (Fig. 3.15);

- Release the spring and remove the top plate 11 (see. Fig. 3.11) valve springs and the springs 12 and 13;

- Remove the valve from the cylinder head from the combustion chamber;

- Remove the other valves in the same way;

- Remove the valve stem seals 14;

- Remove the bottom plate 15, the valve spring;

- Put the sets of details for each valve in separate labeled bags for subsequent installation on the places.

Cleaning and washing details. Before checking the condition of details, do the following:

- Remove the remnants of the old gaskets and sealant cylinder head wooden or plastic scraper;

- Clean the cavity in the cylinder head with a wire brush;

- Clean the combustion chamber of the sludge, wash the cylinder head solvent;

- Rinse and blow compressed air oil channels and channels of the cooling system of the cylinder head.

Troubleshooting cylinder head comprising the steps of:

- Check the cylinder head for the presence of chipping, cracks and other damage. If there are cracks, replace the head;

- Check the mating surfaces for nicks, deep scratches and other damage. If these defects can not be eliminated by grinding plane, replace the cylinder head;

- Check the flatness of the mating surface of the cylinder head using a straight edge and feeler gauge (Fig. 3.16). If the gap between the edge lines and the surface is greater than 0.1 mm, the head must be replaced;

- Visually inspect the valve seats. When the valve seats traces of wear or stick, the seat should be sanded. Profiles valve seat shown in Fig. 3.17 and 3.18. After polishing is necessary to insert the valve seat, press it all the way to the saddle and check the distance A (Fig. 3.19) from the end of the valve stem to the upper surface of the cylinder head. The minimum allowable value of the distance to the intake valves 33.8 mm for the exhaust valves - 34.1 mm. If it is less, the cylinder head needs to be replaced. After any processing of saddles of valves necessary to perform their grinding valves;

- Measured values of the inner diameter of the valve guides. If the values exceed the maximum permissible value, replace the valve guides at the station.

Troubleshooting parts of the valve mechanism.

Inspect the valve plates. In the presence of them pitting, burn-through, cracks and wear, replace the valves.

If the condition of the valve is satisfactory, measure the diameter of the valve stem at several points with a micrometer. With significant discrepancies measurement values, ie, when worn rod, replace the valve.

Before installing the valves need to grind them using lapping paste - a mixture of fine abrasive powder with engine oil. Apply the paste on the surface of the saddle, insert the valve, install it suction cup fittings pritiki and rotate the tool in both directions, periodically pressing the valve seat. After finishing lapping Clean all parts of dirt and residues of paste. Check the fit of the valve to the seat - on the seat and the valve plate must be solid matte belts width of about 2 mm.

Inspect the valve springs. If there is any damage, they must be replaced. Measure the length of the springs in the free state and compare these values with new springs. Install the spring on a flat surface and check the deviation from the axis (Fig. 3.20). If at least one of the valve spring is bent, replace both of its springs.

Look crackers and grooves on the valve stems for the installation of crackers. If there is any damage, replace the parts.

When disassembling the cylinder head valve seals were removed, they must be replaced.

Assembly of the valve mechanism is performed in the following sequence:

- Lubricate the valve stem and guide bushing with clean engine oil, insert the valve;

- Insert the bottom plate of the valve springs;

- Wipe the engine oil from the top of the valve stem;

- Set the plastic sleeve or wrap adhesive tape bore of the valve stem for installation of crackers for protection from damage working edges of the valve stem seal during installation;

- Lubricate with fresh engine oil sealing lip of the valve stem cap 2 (Fig. 3.21) and place it into the mounting frame 1;

- Press them to stop at the end of the valve stem seal valve guide careful hammer blows on a mandrel, having a mandrel strictly along the axis of the guide sleeve;

- Remove the plastic sleeve or tape with the valve stem;

- Install the valve spring and the upper plate;

- Compress the valve spring a special device (see. Fig. 3.15) and establish crackers, propping up the valve from the combustion chamber, then slowly remove the adaptation for compression of springs;

- Gather the valve mechanisms in a similar way;

- Hit the end of the valve copper hammer so that he opened and all the parts of the valve mechanism fell into place.