Cleaning
1. A thorough cleaning of the cylinder head and valve train components, followed by a detailed inspection of their condition, will help determine the approximate amount of restoration work to be done.
Note. Severe overheating of the engine can lead to deformation of the cylinder head and violation of the flatness of its mating surfaces.
2. Scrape off all traces of the old gasket material and sealant from the mating surfaces of the cylinder head, intake manifold and exhaust manifold - try not to damage the surfaces. The use of a special softener, which should be pre-impregnated with adhering deposits, will greatly facilitate the work.
3. Remove all traces of scale from the walls of the water channels.
4. Thoroughly clean all accessible cavities and openings with a stiff wire brush. In case of severe contamination of the channels, head cleaning should be entrusted to specialists.
5. "Drive away" with a suitable tap for each of the bolt holes, removing corrosion products from the thread, traces of old sealant and restoring damaged turns. If you have access to a compressed air source, blow out the holes to remove chips and small debris.
Attention! Remember to wear protective goggles when using compressed air!
6. Use a wire brush to clean the threads of the intake manifold and exhaust manifold studs.
7. Wash the head with solvent and dry thoroughly. The use of compressed air will significantly reduce the drying time and will guarantee the quality of cleaning hard-to-reach cavities and holes.
Note. Various kinds of compositions for removing traces of soot, which greatly facilitate the cleaning procedure, can be purchased at many car accessories stores. Remember that these types of products are usually chemically aggressive and must be used with appropriate precautions - strictly follow the manufacturer's instructions, usually given on the container label.
8. Wash the valve rocker arms with solvent, then dry them thoroughly. The use of compressed air will greatly facilitate the procedure (don't forget to wear safety glasses).
Note. On VTEC-equipped models, be sure to rubber band the intake rocker arms.
9. Wash in solvent and thoroughly dry the valve springs, their plates and crackers of split locks. Try not to mix up the components.
10. Scrape off the bulk of deposits formed on the surfaces of the valves, then with a wire nozzle to an electric drill, finally clean the surfaces of the valve stems and plates - make sure that the valves are not mixed up.
11. Remove and thoroughly clean hydraulic lifters/valve clearance adjusters (VTEC). Place the removed components in an organized manner.
Note. Jet (s) oil sprays at this stage should be removed and thoroughly cleaned. On 4-cylinder engines, the jets are located at the top of the head, on V6 engines, in the cylinder block (under the head).
Status check
Note. Before deciding on the need to machine the cylinder head, carefully check its condition. After carefully studying the material presented in this subsection, make a list of components that need special attention.
Cylinder head
1. Carefully check the cylinder head for signs of coolant leaks, cracks or other damage. A cracked head must be replaced without fail. If there is no certainty in determining the condition of the head, it should be sent for verification to a car service workshop. If repair is not possible, replace the defective head.
2. Using a flatness gauge and a blade-type feeler gauge, check the head mating surface for signs of deformation. If the flatness exceeds the value allowed by the standards (see Specifications), the head must be sent to the groove in the mechanical workshop.
3. Check the condition of the valve seats in each of the combustion chambers. In case of revealing cavities, cracks, traces of burnout, the head should be subjected to a special restorative repair, the implementation of which lies beyond the qualifications of an average amateur mechanic and should be entrusted to car service specialists.
4. Using a DTI gauge, evaluate the backlash of the valve stems in the guide bushings. The valve should be raised from the seat approximately 1.6 mm. The total valve lateral runout should then be divided by two to determine the valve seat clearance in the valve guide. Compare the results of the calculations made with the requirements of the Specifications. If there is any doubt about the correctness of determining the condition of the components, their verification should be entrusted to the specialists of the car service workshop.
Valves
1. Carefully check the valve surfaces for signs of uneven wear, deformations, cracks, cavities and burn marks. Assess the degree of actuation of the valve stems. Check for cracks in the necks of the rods. Rotate the valves to check for bending of the stems. Check for cavities and signs of excessive end wear. Identification of any of the listed defects requires the delivery of valves for refurbishment to a car service workshop.
2. Measure the width of the cylindrical part (girdle) plates of each of the valves). If the belt width is less than the value specified in the Specifications, replace the valve.
Valve components
1. Assess the degree of wear of the end parts of each of the valve springs, check the springs for cavities. Installing each of the springs vertically on a flat surface, check the severity of their facing. Springs with violation of trimming, as well as sagging ones, must be replaced.
2. Measure the free length of the valve springs, compare the results of measurements with the requirements of the Specifications. If the spring is shorter than the lower limit, it is sagging and must be replaced. Also check the forces developed by the springs for compliance with regulatory requirements (it is better to entrust this work to the specialists of the car service workshop). In the absence of confidence in determining the condition of the springs, it would be more correct to replace them.
3. Check the spring plates and crackers of their split locks for cracks and signs of wear. All parts in doubtful condition should be replaced with new ones in order to avoid the development of defects in the future.
4. Replace any defective components found.
5. If the valve components are significantly worn, which is quite likely for an engine in need of overhaul, assemble the valve assemblies, install them in their regular places in the head and proceed to the valve maintenance procedures (see Section Valve maintenance).