Until the 1980s, the vast majority of automobile manufactures painted their engine blocks. Each company used a different color, and sometimes those colors changed over time. Although the paint was extremely durable, it was not immune to the passage of time, and the paint commonly began to lose its color and chip away. Repainting an engine block is quite simple and the engine does not have to be removed, although painting the engine while still in the engine bay does require careful attention to detail to avoid painting an unintended component.
Disconnect the negative battery terminal from the battery to avoid the risk of fire, as engine paint is highly flammable. The negative battery cable can be identified by locating the "---" symbol that is stamped into the battery case next to the cable. The negative battery cable attaches to the battery with a clamp, which features a single bolt and a single nut. Loosen the bolt with a wrench until the cable is loose, then pull the cable off of the battery.
Remove the air-cleaner assembly. Most air-cleaner assemblies attach to the top of the carburetor with a single wing nut located at the top of the assembly. Twist the wing nut in a counterclockwise direction to remove it, then lift the assembly off of the carburetor. Some air-cleaner assemblies use a number of metal clasps to hold the upper and lower portions of the assembly together. Pry the clasps off of the assembly with a screwdriver, then lift the assembly off of the carburetor.
Wrap plastic bags around the carburetor, distributor, alternator and ignition coil. Before the engine can be painted, it must be cleaned with an engine degreaser and water. If either enters the carburetor, the engine may have difficulty starting later. Water can also destroy the electrical components within the distributor, alternator and the ignition coil. To avoid these risks, wrap each component with a plastic bag. The bags will also prevent these components from being inadvertently sprayed with paint when the block is painted, so they should not be removed until the new paint has dried.
Clean the engine with engine degreaser. Engine degreasers are commonly available at most automotive parts stores in an aerosol can. Liberally spray the degreaser onto the engine and allow it to sit for at least 15 minutes, then spray the degreaser off the engine with a garden hose.
Cover the engine's accessories and hoses with butcher's paper and masking tape. The accessories include the power steering pump and the air conditioning compressor. Also be sure to wrap the engine's hoses with paper and tape, as these should not be painted.
Apply a single coat of high-temperature engine paint to the engine block, then allow at least two hours to pass for the paint to dry. It is important to only apply paint specifically designed for engines, as general-purpose paint will quickly burn off due to the heat of the engine.
Apply a second coat of paint to increase the durability of the paint job, then allow at least two hours to pass for the paint to dry.
Remove the butcher's paper, tape and the plastic bags from the engine's components, then reattach the negative battery cable and air-cleaner assembly to complete the job.
