Coatings Get Technical

Coatings are an exciting materials technology that is reshaping the way engineers think about some of the basic engineering. If you look around, coatings are everywhere. Coatings can be found everywhere from drill bits to NASA.

Swain Tech Coatings has developed coatings with special properties to protect internal engine parts from damage. In addition to damage protection, coated parts can provide improved throttle response, lower coolant and oil temperatures, and most important, make more power.

Coatings Get Technical Bearings
Swain Tech coated bearings reduce rotational friction and improve wear life of both the bearings and journals.

 

Coatings Get Technical Coated Header
White Lightning™ is the only performance exhaust coating available. Scavenging is improved and under hood temperatures are reduced with White Lightning™.

 

Coatings Get Technical Internal Parts
Coatings on pistons, combustion chambers, valves, bearings, manifolds, valve springs, cranks, rods and other parts all will improve the power and/or durability of any motor.

To understand just why these coatings work, you have to look at an engine from a thermodynamic point of view. The cams, valves, pistons, rods, crank and all the other parts of an engine are simply there to convert the heat energy of combustion into rotational force, to move the car forward. The job of an engine’s cooling systems, be they air, oil, water, or a combination, is to remove enough heat so that the engine parts do not self destruct. On one hand we are creating heat to use it for energy, and on the other hand we are working hard to remove that heat. If that doesn’t sound too efficient, you’re right!

The typical internal combustion engine manages to convert a mere 25% of the fuel’s energy into useful work at the crankshaft. Where does the rest of the energy go? A large portion, about 35% goes right out the tail pipe. Another big chunk of energy goes out the cooling fluids in a car, such as coolant and oil. The approximately 20% of power lost in cooling is nearly equal to the net power produced. Part of this is simply heat from combustion, and a smaller part is frictional heat from the engine’s rotating parts. The remaining 20% of power is lost to radiated heat, from the exhaust system, crankcase and coolant jacket and pipes.

Though an investment that only paid twenty five cents on the dollar would be disappointing, 25% is actually a good return on an automobile engine. How can some of this lost energy be recuperated to improve the thermal efficiency of the motor?

Swain Tech Coatings take a significant step toward improving the efficiency of the motor. These coatings are developed to make better use of the energy by directing heat energy, reducing friction and improving cooling efficiency.

Swain Tech Coatings is the leader in performance coatings. Swain Tech’s founder Dan Swain used both his racing and ceramic engineering background to develop the first successful piston coating in the early 1970’s. Swain’s ceramic thermal barrier is now in its fifth generation of development and the bond strength and durability of these materials is unmatched.

The engineers at Swain have as many people calling about coatings to improve durability as call to get more power. Most of the things done to increase performance also increase the stress on an engine. If we raise the compression to increase the power, we get higher output at the expense of increased thermal loading. The same holds true if we increase airflow to better fill the cylinders. To get more horsepower by turning the engine at a higher rpm, the mechanical loading on components increases tremendously. Coatings will increase durability by reducing the thermal and frictional loads on the engine.

How do coatings work to increase horsepower? There are a great number of ways that coatings function. To simplify, we’ll deal with the four basic ways that coatings help the racer:

1. direct heat to where it is needed
2.  reduce friction
3. block heat from where you don’t want it
4. improve heat radiation.

If that sounds like a tall order for a single coating, you’re exactly right. No one coating can do all of the above, so Swain Tech has formulated specific coatings for each problem and environment.
If you can control the heat energy, you simply make more power. Coatings help keep the heat in the combustion chamber and out of the piston, pin, rods and oil. Experts using coatings in their race engines tell us that the typical results one can expect from an engine with thermal barrier coatings include some increase in fuel mileage, better throttle response due to a hotter combustion chamber, an immediate difference in oil temperature, with the rod and wrist pin running cooler. Oil burn on the back of a piston becomes nonexistent. Anti-friction coatings on piston skirts, valve springs and valve stems reduce scuff and frictional losses.

Here are where the highest power gains are made. Swain typically coats the top of the piston, the combustion chamber and exhaust ports with a ceramic thermal barrier coating. By insulating the combustion process, higher output with less stress on components is achieved.

Over the years, coatings have received a bad rap for lack of adhesion. Swain Tech is the original engine coating company. Many people have tried to imitate these coatings and some will even look similar to the Swain Tech Coatings, but Swain Tech is the only company developing advanced coatings for high performance applications and they use their exclusive Smart Coat technology which allows the coating to become part of the base metal and will expand at the same rate as the piston. When an intake component failed and was ingested on a race 944 Turbo motor with a Swain coating package, the teardown revealed the intake debris had scratched the cylinder wall. In spite of a foreign object banging around in the chamber, the coatings on the piston dome and combustion chamber were untouched. These coatings are extremely tough and durable.

PISTONS
Domes of normally aspirated and mild boost motors are protected with Swain Tech’s TBC ceramic thermal barrier. In its fifth generation, TBC uses Swain’s exclusive “Smart Coat” technology which tenaciously bonds the coating to the base metal and will expand at the same rate as the piston. Motors running nitrous oxide, high boost turbo’s, super charged, and nitro motors run Gold Coat, a unique ceramic thermal barrier specifically designed to deal with the high temperature heat spikes and high temperature oxidation associated with these motors.

Poly Moly is the standard skirt coating which has an extremely low coefficient of friction and reduces scuffing caused by piston movement. High revving, short skirt, and heavy side load piston skirts are coated with Swain’s latest development in skirt coatings, PC-9. PC-9 can also be used to take up excessive piston to wall clearance.

CYLINDER HEADS
TBC is applied to the combustion chamber to improve combustion temperatures while reducing overall head temperature. When the combustion chamber is coated, the valve faces are set in place and coated at the same time. Often, the exhaust ports and even the back side of the exhaust valves will be coated to further manage the heat of combustion. All heads benefit from TBC, but these gains are heightened with aluminum heads.

EXHAUST
The purpose of Swain Tech’s exhaust coating should not be confused with the lower tech cosmetic coatings (shiny or colored) that are available. Those coatings form an attractive finish, but do very little to insulate the exhaust or increase power. Swain’s external thermal barrier holds the heat energy in the header, which serves two purposes. It makes engine compartments cooler, and it keeps exhaust gas velocity high, improving scavenging. The latter is especially important in turbocharged engines, where a coated exhaust manifold can improve turbo response.

VALVE SPRINGS
Swain Tech has worked with top engine builders to solve valve spring failure by developing a coating to reduce fatigue and heat. Cooling and longevity are two of the advantages of this valve spring coating. Highly stressed race engines can now run valve springs for an entire season without wearing them out.

BEARINGS
Swain coated bearings do not appreciably change the shell dimensionally, but does a great job of improving both bearing and journal life. These oil attracting low friction coatings allow parts to move more freely and provides back up lubrication if oil starvation occurs.

In addition to their automotive coatings, Swain Tech also has an extensive industrial division. Here, they manufacture and coat components, apply unique materials such as Hastalloy, Ceramics, Stellite, Tungsten Carbide, Stainless Steel, Silver, and many other materials to solve the problems of wear, corrosion, friction and heat transfer. The continued technology transfer within Swain Tech is continuously leading to unique coating solutions.

Thanks to James Sly for his technical input.