In a garage setting, you can disassemble, clean, inspect, reassemble the cylinder head, and deliver it to the dealer's service center or to specialized workshops for valve repair.
The following types of work are performed in a service center or specialized workshop: removal of springs and valves, grinding or replacement of valves and guide bushings, checking and replacing springs, retaining rings and crackers (as needed), replacing valve stem seals, replacing valve parts, checking the free height of the spring. If the deviation from flatness exceeds the norm, the cylinder head must be ground.
After inspection and repair of the valves and their components by experienced personnel, the cylinder head is completely restored. Before installing the cylinder head, rinse it again to remove any remaining abrasive material from grinding the head or lapping the valves. If possible, blow out all passages and openings with compressed air.
Valve grinding
If the valve chamfers and seats have minor wear or new valves are installed on unworn seats, the valves must be ground to the seats. The lapping operation is performed as follows.
Apply a small amount of coarse abrasive paste to the seat chamfer. Insert the valve into the guide bushing and, by turning and pressing the valve, grind it against the seat. To perform this work, you will need a device in the form of a tube with a piece of rubber hose inserted inside. Lapping can also be done with an electric drill by inserting this device into the chuck. During the grinding process, periodically lift the valve to check the result and redistribute the grinding material.
When a smooth, continuous band has formed on the valve head or seat chamfer, remove any remaining coarse abrasive paste and continue lapping with a fine paste.
After grinding all the valves to the seats, thoroughly wash the grinding areas with kerosene to remove any remaining abrasive, wipe with a rag and, if possible, blow with compressed air. Abrasive residue in the cylinder head can cause increased wear of components.
It should be noted that if old valves are ground in excessively, the position of the belt may be disrupted and become unacceptable. When lapping new valves onto old seats, excessive lapping can cause pockets to form.