GM 91177344 Cylinder Head Assembly (On Esn)

Regardless of whether or not the head was sent to an automotive repair shop for valve servicing, make sure it's clean before beginning reassembly. If the head was sent out for valve servicing, the valves and related components will already be in place. Install new seals on each of the valve guides. Using a hammer and a deep socket or seal installation tool, gently tap each seal into place until it's completely seated on the guide. Don't twist or cock the seals during installation or they won't seal properly on the valve stems. Beginning at one end of the head, lubricate and install the first valve. Apply moly-base grease or clean engine oil to the valve stem. Drop the spring seat or shim(s) (if used) over the valve guide and set the valve spring(s) and retainer in place. On DOHC engines, make sure that the inner and outer springs are installed with the large-pitch end at the top of the spring and the small-pitch end at the bottom. Compress the springs with a valve spring compressor and carefully install the keepers in the groove, then slowly release the compressor and make sure the keepers seat properly. Apply a small dab of grease to each keeper to hold it in place if necessary. Repeat the procedure for the remaining valves. Be sure to return the components to their original locations-don't mix 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 don't automatically assume that it is). The measurement is taken from the top of each spring seat or shim(s) to the bottom of the retainer. If the height is greater than specified, shims can be added under the springs to correct it. Caution: Don't, under any circumstances, 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 camshaft, then install the camshaft, rocker arms, springs and shafts. On 16-valve engines, tighten the bearing caps to the torque. Reinstall the distributor case, using a new O-ring.

Old gasket material and sealant can be removed from the cylinder head gasket and other surfaces using specialized gasket removal solvents.

Clean and inspect all threaded fasteners and ensure that the threaded holes in the block are clean and dry.

New and rebuilt cylinder heads are usually available at dealerships and auto parts stores.

Reconnect the negative battery cable, start the engine, readjust the ignition timing if necessary, and check for leaks and proper operation.