The valve mechanism of the 231 cu in V6 engine is slightly unique relative to the other GM engines in the sense that it's an inherently valve lash adjuster. If the grinding is to be done on the valve seat on the cylinder head or the valve face then there will be change happen in the height of the stem of the valve above the head. According to GM, if the valve and seat have been refinished sufficient number of times to make the end of the valve stem about 0.050 in above its usual height, the stem should be ground to the standard height. Starting here involves the process of the removal of the cylinder head which should be placed on a clean surface. Valve spring can be compressed using the right spring compressor, you ought to then remove the valve spring cap key, and then release the tool to allow the removal of the spring and the cap. Remove the valve seals and unscrew the valves and having arranged them in numerical sequences set them with the seat faces downwards on a block of wood or cardboard. Scrub the cylinder head and inspect it for charring, pits, cracks and other signs of wear and tear; the valves may have to be re-sharpened or replaced as may be required. If re-grinding of a valve produces a sharp edge, the valve should be discarded since this causes overheating. Correct angle of the valve face is 45°. If the stem of a valve has more than free running clearance in it's guide it should be replaced with an oversized valve thus making it a job for a dealer or a machine shop. The valve seats should also be trued up to 45°, it is a small operation that will require the services of a dealer or a machine shop. When doing this, the valves are very lightly ground to the seats using course carborundum paste and suction cup grinding tool having to lift the value to provide an even spread of paste. After one has obtained an even surface with a dull matte finish, wipe the paste and do the same with fine carborundum paste to get a smooth ring of the grey matte finish. Remove any debris that may be present from the grinding compound and it is important to note that new valves should not be lap ground as this will compromises the surface plating. Finally thee valve stems and guides should be lubricated with engine oil before the valves are put back into their respective positions. Replace intake valve seals and do not replace exhaust valve guide seals. lightly place the valve seal over the valve stem and squeeze it down to the top of the guide and by using an installation tool you can place the seal on the valve guide until it takes the best fit. Tighten the springs only to a degree that allows fitting the keepers to be fitted without over compressing the valve seal. Last of all, replace the intake and exhaust valve springs which can be fitted in either direction of each other as well as the valve spring, the cap and the cap retainer.
