Dry Film Lubricants - These are the friction reducers, sometimes called "solid film lubricants." Far surpassing the benefits of bygone molybdenum disulfide suspended in lubrication oil, dry film lubricants are highly effective in reducing friction, heat, and surface galling. Since the lubricity portions of these materials are what provide the benefits, it's important that a good binder be utilized to keep the lubricants in place. Aside from gains made in friction reduction (particularly friction horsepower), the companion benefit is in heat reduction at the working surfaces.

Chemical or Corrosion Resistant Coatings - Materials in this category serve two fundamental purposes; (1) extended product durability or use life and (2) maintenance of appearance. We'll touch on specific areas where these coatings are of value a bit later.

In the same order they were previously presented, let's examine some specific uses for the coatings categories discussed.

Thermal Barriers - Here, the obvious areas are the combustion space and exhaust gas path. As mentioned earlier, my first and disappointing experience coating piston crowns showed power gains but damaged parts. Fortunately, with today's coatings technology, such problems are passe. So as you might expect, coating piston tops (and bottoms), combustion chambers (in certain applications), the faces of intake and exhaust valves, and complete header systems with these type of heat-retention coatings can be of particular benefit. Keep in mind that power equates with heat in a controlled environment. Therefore, combustion heat lost to cooling systems, combustion surfaces (all of them), and along the exhaust path can combine to reduce net power. Your best bet is to either consult with your choice of parts manufacturer already providing coated parts, or identify a good supplier of coatings materials if you elect to do the job yourself. And don't rule out the latter. Given the current state of some "kits" that are user-friendly to the engine builder, you can also get good results by these methods.

Thermal Dispersants - Wherever you find that heat buildup is a concern, these are the materials to consider. Such components as brake parts, oil pans, radiators and intake manifolds all can fall into the need for rapid heat transfer or control. In areas where continual and/or repeated temperature spikes occur and you need to move heat more quickly away from these locations, consider these coatings to be of value.

Dry Film Lubricants - Remember, simply stated, friction horsepower is the arithmetic difference between indicated horsepower and brake horsepower. Therefore, the lower the friction horsepower, the higher the brake horsepower. So, by the use of dry film lubricants in areas that will net a reduction in friction horsepower, you can expect net power gained at the flywheel. Also expect a reduction in both surface and component operating temperatures. Applicable parts include valve springs, engine bearings, camshafts, and piston skirts and pins. Once again, you have the options of either selecting precoated parts or consulting with one of the coatings providers. Should you decide on the first option, it's wise to spend time talking with the manufacturer about the material (and its benefits) on any precoated component.

In this section, it may be helpful to discuss the benefits from coating certain major engine components. We'll include a few reasons and their basis, too. Our intention here is to stimulate some thoughts to the extent you'll begin to identify other parts and how they may benefit from coatings that address specific problems.

Valve Springs - Smokey once contended that valve springs raise the operating temperature of engine oil more than combustion heat. He'd already discovered that with his own version of today's "Spintron" spin fixture. Included in that discussion was his belief, other than valve float, that heat foreshortens spring life more than anything else.

Essentially, there are two sources of heat in a valve spring. One is derived from the friction of a spring moving against other surfaces (inner springs, harmonic dampers, etc.) and the other from the "flexing" or "working" of spring material during normal operation. Studies have shown that a valve spring is never motionless, even when the valve is seated. Residual energy and harmonics traverse an otherwise "static" spring, while the valve is on its seat. Consequently, heat within spring material is continually being generated. Heat is a principle source of damage to springs and, since valve springs are cooled by oil, you can expect other parts of the engine to correspondingly experience increased oil temperature.