Q: How should the Cylinder Head be prepared for reassembly after valve servicing on 1993 Pontiac Grand Prix?
A: Regardless of whether the head was sent to an automotive repair shop for valve servicing, ensure it is clean before beginning reassembly. If the head was sent out for valve servicing, the valves and related components will already be in place, so start the reassembly procedure with the installation of the spring seats or valve rotators (if equipped) before the valve seals. Install new seals on each of the valve guides by gently tapping each seal into place with a hammer and a deep socket or seal installation tool until it is completely seated on the guide, taking care not to twist or cock the seals during installation to ensure proper sealing on the valve stems. Beginning at one end of the head, lubricate and install the first valve, applying moly-base grease or clean engine oil to the valve stem. Position the valve springs (and shims, if used) over the valves, compress the springs with a valve spring compressor, and carefully install the keepers in the groove, then slowly release the compressor to ensure the keepers seat properly; a small dab of grease can be applied to each keeper to hold it in place if necessary. Repeat this procedure for the remaining valves, ensuring that all components are returned to their original locations without mixing them up. Check the installed valve spring height with a ruler graduated in 1/32-inch increments or a dial caliper; if the head was sent out for service work, the installed height should be correct, but it is important to verify this measurement from the top of each spring seat, rotator, or top shim to the bottom of the retainer. If the height exceeds specified limits, shims can be added under the springs to correct it, but do not shim the springs to the point where the installed height is less than specified. Apply moly-base grease to the rocker arm faces and the pivot balls, then install the rocker arms and pivots on the cylinder head studs, except for specific engine types. For those working on a Quad-4 engine or 3.4L V6, install the camshafts, lifters, and housings on the head as directed.