Owing to the sensitive operations of the job and the special tools and equipment involved, the work that involves resurfacing of the valves, valve seats, and the valve guides which is normally called the valve job should be conducted by an expert mechanic. It also enables a home mechanic perform a basic 'tear down' of the head, carry out initial preparation of cleaning and inspection before reassembling for transport to a dealer service department or an auto machine shop where the actual service is done. The inspection enables the understanding of the status of head and valve train parts; the work needed and new components when dealing with an automotive machine shop. Dealer service department or automotive machine shop can perform the following on valves: valve and springs are removed, valves and valve seats are recondition or replaced, valve guides are reconditioned, valve springs, spring retainers and keepers checked and replaced as required, new valve seals are installed, valve components are reassembled, installed spring height is checked and corrected if necessary. Also, depending on the condition, the surface of the cylinder head gasket will be restored if warped. After the valve job has been done by a professional, head will be as good as new. On its return it should be cleaned again before being bolted onto the engine to remove any loose metal particles and fine abrasive grit that may be left after the service of valves or a resurfacing of the head; and if possible, use compressed air to blow out all the oilways and passages.
