The valve mechanism of the 231 cu in V6 engine is peculiar because it does not have a valve lash adjustment provision like most GM engines. If the valve seat on the
Cylinder Head or the valve face is ground it alter the height of the valve stem from the surface of head. GM says that if valve and seat have been refinished to such an extent that the end of the valve stem will be 0.050 inch higher than in its normal position, the required correction must be made by grinding off the stem end to bring valve stem back to standard height. First, take off the cylinder head and put it aside on a clean flat surface which will be referred to as surface A. Using a good spring compressor like; GM tool J-8062 compress the valve spring to remove the valve spring cap key, and after that ease of the tool to pull out the spring and cap off. Take out and dispose the valve seals stacking the valves in order in a block of wood or a hard cardboard for replacement. Wash and inspect the cylinder head for signs of damage, it is also important that one checks on the valves for pitting, the burnt marks as well as seating; the valves shall be re-condition or replaced, if a valve after re-grinding has sharp edge, it should be chucked away. The increment in the valve lift, as observed on the stick at the valve stem end, causes the clearance in the guide if excessive; to rectify this will require the installation of an oversized valve and should be done at the dealer or machine shop. Because the valve seats should be trued up to 45° in the refining stage, valve lapping should not be done. Coat the stems and guides with engine oil prior to reinstalling the valves, and replace intake valve seals, but do not use new exhaust valve guide seals. Go over the valve stem slowly and let the flattened part of the valve seal come to rest atop the valve stem, then use some installation tool such as the GM tool J-22509 to slide the valve seal over the valve guide in a way that the upper inside surface of the said valve seal reaches the top of the valve guide. Squeeze the springs only to assemble keepers since tightening the valve's seal can be affected when the springs are compressed tightly. Lastly re-attach the intake and exhaust valve springs as they can be placed in upside down manner then re-attach the valve spring, cap, and cap retainer and finally the cylinder head.