Attention! Wait until the engine has completely cooled down before starting work.
Removing
1. Remove timing chains with sprockets (see Section Removing, checking the condition and installing the timing chain and sprockets).
Attention! Try not to remove the crankshaft from the TDC position at the end of the compression stroke of the first cylinder.
2. Moving in the reverse order shown in the illustration, remove the bolts securing the rear timing cover.
3. Remove the rear timing cover from the engine.
Note. If cover "got used to" to any of the heads or to the block, tap it with a hammer through a wooden block. In extreme cases, cut through the layer of cured sealant with a putty knife. In order to avoid a violation of the tightness of the fit of the components, in no case do not try to pry the cover with a lever under the mating surface.
4. Remove the lower section of the inlet pipeline (see Section Removal and installation of the inlet pipeline).
5. Remove the camshafts and valve lifters from the cylinder head (see Section Removal and installation of camshafts and valve lifters).
6. Label and remove remaining components from the head, such as cooling path hose fittings, tubes, cables, communication lines, etc.
7. Using a bar wrench of the appropriate size in several steps (1/4 turn per approach) Gradually loosen the head mounting bolts until they can be turned out by hand. To avoid deformation of the head, loosening the fasteners should be done in the reverse order of tightening them.
8. Remove the head from the cylinder block. If necessary, carefully pry the non-separable head with a pry bar under the projection of the casting at the level of the mating surface.
9. After removing the external components from the head, prepare it for cleaning and checking the condition.
Note. A description of the procedure for checking the condition of the cylinder head is given in Part General engine overhaul of this chapter.
Installation
1. The mating surfaces of the head and block must be absolutely clean and dry.
2. After scraping off the rest of the gasket material and carbon deposits, wipe the surfaces with a rag soaked in acetone. The presence of traces of oil on the mating surfaces at the time of installation of the head can lead to a violation of the tightness of the gasket fit and, as a result, the development of leaks. When processing the block, plug the cylinder bores with rags to prevent small debris and various foreign objects from getting into them (as a last resort, vacuum the cylinders thoroughly).
3. Check the mating surfaces of the head and block for deep scratches, nicks and other damage. Light defects can be removed with fine-grained sandpaper. In more severe cases, the only alternative is to remake the components or replace them.
4. With a tap of the appropriate size, drive the threaded holes for the head mounting bolts. When finished, blow out the holes with compressed air.
Note. Remember to wear protective goggles when working with compressed air!
5. Estimate extent of an extension of fixing bolts. If the difference in the diameters measured at the indicated points exceeds 0.11 mm, the corresponding bolt must be replaced. Alternately clamping the bolts suitable for further use in a vice by the head, go through their threads with a lerka - the presence of old sealant, dirt and corrosion products in the threads leads to a discrepancy between the actual tightening force of the fasteners and the indications of the torque wrench indicator.
6. Evaluate the degree of flatness of the head (see part General engine overhaul this chapter). Check up also interfaced with the inlet pipeline and a final collector of a surface.
7. Install the removed external components on the head.
8. Clean the rear timing cover and its fastening bolts from traces of old sealant
9. Apply fresh RTV Sealant to the cap mating surface according to the diagram shown. Insert new o-rings into the corresponding mounting sockets on the front side of the block. Putting on the guide pins, press the rear timing cover against the surfaces of the block and cylinder heads, then, moving in a strictly defined order, screw in and tighten the mounting bolts with the required force.
10. Insert camshafts and valve lifters into the head (see Section Removal and installation of camshafts and valve lifters). Install timing chains (see Section Removing, checking the condition and installing the timing chain and sprockets). Further assembly is carried out in the reverse order to the dismantling of the components.
11. If during the maintenance of the head the components of the valve mechanism were replaced, adjust the valve clearances (see Section Checking and adjusting valve clearances).
12. Don't forget to fill the cooling system and change the engine oil and oil filter (see chapter Settings and ongoing maintenance).
13. Start the engine and check for signs of oil and coolant leaks. Evaluate the correct setting of the ignition timing (see chapter Settings and ongoing maintenance).