Cleaning and checking the status of a head of cylinders

1. Thoroughly clean the head (s) of the cylinder and valve train components, and then make a check of its (their) state that will determine the volume of necessary restoration work on the valve mechanism in the course of engine overhaul.

It should be borne in mind that if in the course of operation of the vehicle have been overheated engine, the cylinder head will probably deformed (broken its mating surface flatness).

2. Scrape off all traces of old gasket material and sealant to the mating surfaces of the head, intake manifold and the exhaust manifold. Avoid damaging the head. Available in special solvents, the use of which allows to soften the gasket material - ask in shops of automobile accessories.
3. Remove from the cooling channels all traces of scale.
4. Small holes clean with a special stiff brush - their brush.
5. All screw holes Run tap the appropriate size, removing corrosion and sealant to restore damaged coils. If you have access to a source of compressed air blow holes, removing the bottom of the chips and debris.

When using compressed air, always wear safety goggles!

6. Stiff brush, clean the threads of bolts supporting rocker.
7. Rinse the head solvent and carefully dry it. The use of compressed air will significantly reduce the drying process of the head and will ensure quality cleaning of all channels, holes and inaccessible cavities.

Useful for cleaning heads and valve train components will use dekarboniziruyuschih compositions. Remember that these formulations are usually very aggressive, and they should be used with extreme caution. Try to adhere strictly to the manufacturer's instructions included with the package.

8. Wash rocker, their support bolts or spherical bearings, mounting nuts or bolts and pushrods in the solvent, then thoroughly dry them (remember to install all components when the assembly is on the former places - be careful not to confuse parts during cleaning). The use of compressed air helps reduce drying of components and ensure thorough purge holes and channels.
9. Wash in solvent all valve springs, their saddles, crackers, plates (or rotary support), then thoroughly dry them. Clean the components of each of the valves alternately in order to guarantee the possibility of setting them when building on the former places.
10. Scrape the thickest sediment layers from the surface of the valve plates, then completely strip the flaps (and plates and rods) with a wire attachment to a power drill. Again, be careful not to mix the components.

1. Carefully check the head for cracks, signs of leaks or other damage to the cooler. In case of detection of cracks a head should be replaced (in case of impossibility of its restoration - consult workshop service centers).
2. With the flatness meter (edge of a steel ruler) and the blade-type probe account the degree of deformation of the mating surface of the head. If the flatness exceeds the allowable for Specifications importance should be given to the head in the groove in the studio Car.

If performed machining the cylinder head of the engine V8, it should also be treated and flanges of the inlet pipeline.

Check the mating surface of the cylinder head of a violation of flatness, tucking blade for that probe the desired thickness in the ribs attached to the surface of a steel ruler (flatness meter) (thickness of the probe corresponding to the maximum permissible value can be determined by flatness Specifications).

4. Inspect the valve seats in each of the combustion chambers. In case of revealing to them the cavities, cracks or burnouts, head valve requires maintenance, the fulfillment of which is outside the qualification of the average mechanic-fan.
5. Determine the clearance between the valve stems and the walls of the guides, for measuring the value of the cross-play of the valve stem using the head mounted on the dial gauge plunger type. The valve should be in the guide sleeve and at a distance of approximately 1.6 mm from its seat. The measured value for determining the magnitude of the backlash clearance should be divided by two. If the measurement are any doubts about the assessment of valve guides, they have to be delivered to more accurately test the workshop service centers (the cost of such testing should be negligible). If the clearance is excessive, guides must be replaced.

To determine the size of the gap between the valve stem and the wall of the guide sleeve can be used by the dial gauge plunger-type (defined by the amount of movement of the rod in the direction of the arrow).

1. Carefully check the working surface of each plate valve for signs of uneven wear, deformation, cracks, cavities and burnouts. Check valve stems for scoring, burrs and pureed sites cervical rods check for cracks. Rotate the valve, make sure that there are no signs of bending the rod. Check the end of the rod in the presence of cavities and signs of excessive wear. Have any of the defects suggests the need for maintenance of the valve mechanism in the workshop of car-care center.

Check each of the valves for signs of wear and damage at these points

1 - The end of the rod 2 - The groove for the installation of crackers of the cutting lock 3 - Pin (less subject to wear part) 4 - Rod (the most part subject to wear) 5 - The working surface of the valve disc 6 - The cylindrical part (shoulder) forming the surface of the valve disc

2. Measure the width (height) of the cylindrical part (belt) forming the surface of the valve disc. If the width of the collar of any of the valves lies below permissible for Specifications limit, the valve must be replaced without fail.

The width of the cylindrical portion (girdle) plates of each of the valves must satisfy the requirements of the Specifications (if the belt is not available, the valve further use of the subject can not).

1. Check the ends of the valve spring on presence of cavities and signs of wear. Measure the free length of the springs and compare the results of measurements to requirements of Specifications in this chapter. If any of the springs is shorter than the allowable value, it is considered a "sagging" and not subject to further use. In order to recognize the spring fit for installation on rebuilt engine needs to check the efforts of compression (in the studio Car with special equipment).

Measure the free length of each of the valve springs using a vernier caliper or a dial.

3. Set each of the springs on a flat surface and check the quality of its trimming. All deformed or "sagging" of the spring must be replaced without fail. Installation springs impaired trimming leads to accelerated wear guides.

Check out all the trim valve springs.

5. Check the plate springs (or rotary support), and breadcrumbs for cracks and wear. All components are in a precarious state must be replaced to avoid the development of defects during reduced operation of the engine.

1. Check countertops rockers (the area of contact with the ends of the bars of pushers and valve stem) in the presence of cavities, scuffs, burrs, roughness and wear. Also, inspect the contact surfaces of the rocker arm and spherical bearings. Check each of the rocker arm with bolt and nut securing it for cracks.
2. Check the ends of the bars of pushers on presence of traces of rubbed and excessive wear. Roll the pushers on a flat surface (large fragments of window glass) to identify their bending.
3. Check bolt holes for mounting the rocker arms in the cylinder heads for damage of the threads.
4. All damaged or excessively worn parts must be replaced.
5. If during the inspection revealed poor overall condition of the valve mechanism and the wear of the components in excess of permissible limits, which is a normal phenomenon in need of major repairs of the engine, set the valve train components back into the head and read the guidelines for the maintenance of valves (Section service valves).