Do I need new valve seat inserts? Are they worth it?
Question:
l recently bought a 1958 Lincoln Continental that was restored several years ago. The car still looks beautiful, but it runs rough. When I bought it, the previous owner told me it just needed a tune-up. After I bought the car, my mechanic told me it had a burned exhaust valve and he recommended a complete valve job. After the heads were removed, the machine shop recommended that I pay them to install new valve seat inserts for an additional $150. Are the inserts worth the money?
Answer:
Whether it’s worth investing in valve seat inserts depends on the condition of the heads and how you intend to use the car. It’s not uncommon for cars that are almost 40 years old, like your Lincoln, to have had several valve jobs over the years. As part of each valve job, the seat area of the head for each valve was machined slightly to eliminate burned areas and other imperfections. After several valve jobs, the seats get rather low and the valves “sink” into the head casting. If the valves sink too low it will impair the performance of the engine. One way to fix this is to machine the seat areas of the heads and install valve seat inserts, which return the seats to their original height. Another reason to install valve seat inserts is to make the engine more compatible with today’s unleaded fuels. One of the functions of the lead that used to be added to gasoline was to provide lubrication and cooling for the valve seat area of the heads, particularly the exhaust valve seats. Without lead in the gas, the exhaust valve seats will deteriorate and burn quicker than they would with lead. Your machinist can install valve seat inserts made of a very hard material that does not require leaded gas for lubrication. So if your heads are damaged from several valve jobs and need inserts to restore proper valve height, or if you intend to drive the car a lot and don’t want to worry about possible long-term harmful effects from unleaded gas, the inserts are well worth the additional investment.
