Coating your engine parts...
Coating your engine parts can result in longer life and better performance.
Research has proven that coating parts, especially those in the engine, can yield better performance and enhance the life of a component. Different coatings are designed to and are capable of reducing friction by making a part slicker (lubricity), insulating or reflecting heat, shedding oil, or attracting a coat of oil. Most coatings have a combination of these qualities.
For years, the idea of advanced coatings couldn't break into mainstream acceptance as racers and engine builders scoffed at the stuff as ineffective or unnecessary. Today, as racers are continuing to push the mechanical boundaries in the ongoing search for more performance, coatings of various types are catching on, and fast.
In order to understand the importance of coatings, we need to provide a foundation for what's out there and the strategy behind how to use it. Tech Line Coatings produces and sells coatings that can be applied by the normal engine builder or racer with a minimum of equipment. This allows the "do-it-yourself" racer to get the full benefit of the experience. Now, if you decide you don't want to do it yourself, we'll give you a few alternatives to consider.
A piston can require more...
A piston can require more than one type of coating. A dry-film lubricant can work on the skirts while the thermal barrier coating does the job on the top.
Performance coatings fall into general categories: dry-film lubricants, thermal barrier, thermal dispersant, and corrosion/ chemical resistant. The primary purpose of a dry-film lubricant is to reduce friction. The goal of using a dry film is to protect a part's life and eliminate the horsepower loss brought about by parts rubbing. The loss of friction also leads to reduction of heat, which is critical in a part's life. Dry-film lubricants utilize lubricating ingredients, but need an element to provide bonding to the part. Various combinations of binding and lubricating ingredients allow a wide variation in load carrying ability.
Thermal barrier coatings deal directly with heat. They are designed to protect the part from the intense engine heat or, in the case of exhaust parts where heat is acceptable, keep the heat inside. There are many materials used in the development of a thermal barrier coating, which is also a popular coating with widespread use outside the engine compartment. Ceramics and metallic ceramics are common choices.
Thermal dispersants serve a completely different role. While a thermal barrier protects a part from heat, a thermal dispersant will redirect the heat. The thermal dispersant serves as a guard against excessive heat buildup, which will combat metal fatigue, boiling fluid, metal expansion/distortion, and more. The thermal dispersants can work in conjunction with other coatings to protect parts and the overall engine.
Coatings that inhibit chemicals and corrosion serve as engine protection. Rust can threaten metals and make expensive parts become junk. Maintaining parts is a key to longer engine life and a chemical/corrosion inhibiting coating can serve as a first line of defense. Calico Coatings offers a CT-5 corrosion-resistant coating with oil-shedding ability.
With the formulation of coatings, it's clear that no one coating is designed to do every job. When considering the part, it must be matched with the coating that will serve the need, based on the part's role in the engine's performance.
You may need to mask off areas...
You may need to mask off areas that do not need coating. Simple masking tape will work.
spray 'n' bake Applying the coatings to engine parts can yield the best results if the directions are followed correctly in the proper sequence. It's best to follow manufacturers' guidelines and recommendations for specific applications. These are the general steps to be followed:
1. Clean all parts completely. You must make sure to leave no residue on the parts. In many cases, solvents like lacquer thinner, acetone, or alcohol may do the job. In some cases, brake cleaner in an aerosol can will suffice. Use common sense. Make sure you do your cleaning in an area with plenty of ventilation and wear proper protection. Used parts will require some pre-baking (at about 150 degrees for 30 minutes) before proceeding.
2. Keep the newly cleaned parts in a clean environment or you will have to start over. Wear clean cotton gloves to handle and move the parts. Never touch them with your bare hands because your fingertips contain oils that will diminish the coating application.
3. Sandblast the clean parts. A gravity-feed spot blaster will allow you to gently apply the process. The idea is to etch the surface to create area for coating adhesion. In many cases, a pressure of 45 psi is recommended, using 80- to 120-grit blasting sand. Keep the sand dry to allow better application.
4. Some parts (pistons, valves, head work) will require masking. Regular masking tape will do, but higher-quality tape that leaves little residue will work better. Make sure the area is taped off completely and doesn't allow the coating to leak into areas where it shouldn't go.
You'll need some tools to...
You'll need some tools to do the job. An airbrush (such as a Badger 250 with a 1.00mm-or-finer nozzle) to provide a thin spray will apply the coating. Cleaning solvent and sandblasting will need to be applied before reaching this step.
5. Apply a thin coat of the material. You can use a small airbrush, which is more precise than a standard spray gun. You will not need to measure the coating thickness. Carefully watch the area being coated. When it changes color, you have applied enough.
6. After the coating is sprayed on, the part will need to be heat treated (baked). In general, coatings require a temperature of 350 degrees for about an hour to effectively adhere to the component. Small parts can be placed in a toaster oven. Larger parts require a larger cooking area like a kitchen oven. A used kitchen oven from a secondhand appliance store can handle the task.
7. Parts coated with dry-film lubricants will require a gentle burnishing. The best tool for removing excess is 0000 steel wool. Rub it gently on the surface until the coating seems to disappear (the coating is actually in the surface material).