GM 14095451 Valve Assembly, Exhaust

Look at the heads of the valves for pitting and burning even though placing lot of emphasis in this case on the exhaust valves, examine the valve seat. If there is any indication of pitting or burning in the face of the valve or of the seat, they should be refaced by the dealer while the seat recut. In the event that the refacing of the valve head will diminish it to being less than the specified width, then the entire valve has to be replaced. All carbon deposits from the surface of the valve head and stem should be removed, the valves and valve seats should be cleaned with solvent-soaked cloth and then wiped out with a clean cloth and if possible an air line should be used to blow out the valves, their guides and the valve ports.

Generally inspect the heads of the valves for pitting and burning especially the exhaust valves In addition inspect the valve seating. Certainly if pitting is minimal it should be possible to rectify this by grinding the seats and valves together with coarse and fine valve grinding paste. To grind the valves, smear a little coarser carborundum paste on seat face and suction grinder tool on the valve head, in a semi-rotary motion and now and then lifting the valve to spread the paste evenly. After a matte finish is acquired on both surfaces, remove the paste and go back to using extra fine carborundum paste; as the valve is turned and lifted as necessary. This may be eased with the use of a light spring put under the valve head. When there is a continuous ring of light grey matte finish on both faces the grinding is done. If pitting or burning is more than light, the valve should be refaced by the dealer with the seat recut; if the head edge rubs are low after skimming, then you have no option, but to change the valve. Last, all carbon must be wiped off the valve head and stem, no grind compound should stay in the ports or in the valves guide and valves and seats should be cleaned to perfection with solvent soaked rags, clean rags and lastly, if available blow with an air line.