Friction reduction coatings provide improved lubrication and cooling to extend the life of internal engine components. On bearings and piston skirts, fluoropolymer coatings are designed to help maintain the oil film on the surface. The benefit is reduced friction, improved longevity, and increased horsepower. The coatings are very effective, yet thin enough that they don’t impact bearing or piston-to-wall clearances at all. While the purpose of ceramic coatings on the valve faces is to maintain heat in the combustion chamber, an antifriction coating can also be applied to the valve stem. The resulting friction reduction can help prevent engine damage caused by sticking a valve.
Engine oil not only lubricates parts, but it also carries heat away from internal components. Oil-shedding coatings allow oil to perform its job by carrying that heat away more efficiently. As such, oil-shedding coatings are typically applied to valvesprings, and the inside surfaces of valve covers and oil pans. The more oil these components can shed, the more heat that can be carried away. Other favorable characteristics of these coatings are that they’re highly resistant to chemical acids and bases, and improve oil drain-back and oil management.
Cooler Air Temps
Keeping the temperature of the intake air charge as cool as possible results in a denser air/fuel charge, which increases horsepower. A cooler air intake charge is also more resistant to detonation. While it’s true that header coatings reduce underhood temperature, and therefore the heat that soaks into neighboring components, the intake manifold itself can also be coated. Applying a ceramic coating on the bottom surface of the intake manifold mitigates the amount of heat that will transfer from the hot engine and engine oil into the intake runners. This keeps both the air and fuel cooler. The inside of the intake runners can also be coated, which sometimes improves the laminar flow characteristics of the induction system. In the near future, Jet-Hot plans on conducting extensive dyno testing in-house to measure the performance benefits of our engine coatings.
Coatings and Welding
Since there are often clearance issues with headers, they sometimes need to be cut, welded, or modified for proper fitment. For the sake of simplicity, it is always best to complete these modifications or repairs before sending a set of headers in to get coated. This eliminates the possibility of having a section of tubing where the coating is no longer present. In the event that a section of tubing that has already been coated needs to be welded, the coating must be removed with a grinder. Likewise, the heat of the weld must be increased as well.
Coatings and Dynos
When driving down the road, there is always a steady stream of air that removes heat from the engine compartment. However, this isn’t the case on an engine or chassis dyno. The stagnant air in a dyno cell combined with the heat generated by sustained high-rpm engine operation can exceed the limitations of the aluminum in the coating matrix. This can ultimately cause dulling of the coating surface. To avoid this potential problem, it’s best to use a large fan to help dissipate the heat of the engine and headers during dyno testing. CHP