Invert the cylinder head and clean the carbon from the valve faces and combustion chambers. Use a permanent felt-tip marker and mark the valves for location.
Use a valve spring compressor and compress the valve springs. Lift out the keepers, release the valve spring compressor and remove the valve, spring and spring retainer. Place all parts removed in order so that they can be reinstalled on the same cylinder.
Remove the valves from the cylinder head. Chip away any remaining carbon from the valve heads, combustion chambers and ports. Use a rotary wire brush on an electric drill. Be sure that the deposits are actually removed, rather than burned. Clean the valve faces with a wire wheel taking care not to remove the location numbering. Clean the cylinder head and component parts in an engine cleaning solvent.
Remove the pushrods, and, if hollow, clean out the oil passages using fine wire. Roll each pushrod over a piece of clean glass. If a distinct clicking sound is heard as the pushrod rolls, the rod is bent, and must be replaced.
Remove lifters from their bores, and remove gum and varnish, using solvent. Clean walls of lifter bores. Check lifters for concave wear as illustrated. If face is worn concave, replace lifter, and carefully inspect the camshaft. Lightly lubricate lifter and insert it into its bore. If play is excessive, an oversize lifter must be installed (where possible). Consult a machinist concerning feasibility. If play is satisfactory, remove, lubricate, and reinstall the lifter.