What Should I Expect from Coating My Engine?

Internal engine and exhaust coatings are so widely depended on now that the questions “Do coatings work?” or “Will it flake off?” are obsolete. Now people just want to know, “What should I realistically expect from coating my parts?” Swain Tech Coatings has always been the leader in engine and exhaust coatings. By developing specific coatings to improve internal engine and parts and professionally applying the coatings in a controlled environment, Swain Tech has earned a reputation for quality coatings with durability that is unmatched. Through the years, we have seen small coating shops start up with inferior materials and inflated claims. Some of the inferior materials are so basic they are sold as “do it yourself” coatings. The inferior materials tend to fail in service and the inflated claims cannot be delivered on. Both leave the customer feeling like they have been bitten by the old snake oil. Swain Tech’s professionally developed and applied coatings have been on the track and in the field-tested for over 30 years. The following is an independent, unbiased test that was conducted in cooperation with Circle Track magazine. The purpose of the test was to give engine builders and performance enthusiast a realistic presentation of power gains that should be expected with quality coatings on a high performance motor.

Coated Headers

What Should I Expect Header and Turbo
Swain Tech’s White Lightning™ exhaust coating is the best insulating and most durable exhaust coating available. If you have a heat problem, White Lightning™ is for you.


Coated 4 Cylinder Parts

What Should I Expect Head & Pistons & Springs
Four cylinder motors are a great fit for coatings. With turbo’s, high compression ratios and high rpms, these motors really benefit from thermal barrier and friction reducing coatings.


Coated V8 Parts

What Should I Expect V8 Heads and Pistons
Coatings on pistons, combustion chambers and valves are the internal engine parts that will provide the greatest power gains.

Circle Track sought out a shop that has an ongoing race program. Wayne’s Mail Order Engine Parts has an ongoing test program for small-block two-barrel Chevy Late Model Sportsman engines making them a good fit for this test. Ross pistons, Crower rods, Cam Dynamics camshaft and lifters and other reputable parts were used. To be sure this was an apple to apples comparison all initial clearances were carefully measured and noted on the assembly of the uncoated parts. After assembly, the engine went through normal break in procedures on a test stand. After break in was completed, the motor was bolted to the dyno for 6,500 rpm pulls. The motor was tuned to achieve its best power and the results were recorded. Maximum power was 318 horsepower at 6,000 rpm and peak torque was 305 at 3,500 rpm. All involved were happy with the initial uncoated results and felt the motor would perform well in the real world where the car needs to pull hard out of corners and reach maximum power at the end of straight away.
After the dyno pulls, the motor was torn down and components were sent to Swain Tech to be coated. Thermal barrier coatings on pistons and heads are where the biggest power gains are achieved so those were coated first. We coated the combustion chambers; exhaust ports and piston domes with our TBC ceramic thermal barrier. Piston skirts were coated with our Poly Moly low friction coating to reduce wear, attract lubrication, and provide a solid film of lubrication if the oil film goes away. We also coated the rod and main bearings to improve the wear life of the bearings and journals. The bearing coating provides a back-up form of lubrication to prevent catastrophic failure if you loose oil pressure or oil film. Though the coatings will add a slight film thickness, it would be unusual to need to make a clearance provision for any of the coatings.

Typically, oil-shedding coatings will not make a measurable power difference unless the motor is turning over 6,500 rpm. Despite the fact this motor was expected to make peak power near 6,500 rpm where the oil shedding coatings were not likely to make a measurable power difference, we coated the rods, crank counterweights, oil pan and timing cover with oil shedding coatings to illustrate that the coatings are permanent coatings and that they will survive in a race motor.

After coating, all parts were measured again and the motor was reassembled placing all parts in their original positions to eliminate the possibility of performance differences due to new or different parts. Reassembly confirmed that the coating thickness was thin enough that clearance provisions did not need to be made. After reassembly, the motor bolted to the same dyno in the same shop the initial pulls were recorded on. The results were exactly what you would expect based on years of Swain Tech’s independent dyno test on every type of motor from a basic 5 horse Briggs & Stratton Motor to motors that are found at the top levels of circle track, drag and road racing. With over 30 years of testing, we can confidently state you should realistically expect a 2-5% horsepower and torque gain on a motor with coated pistons and heads.

With no modifications other than the coatings, the dyno pulls clearly showed the torque and horsepower curves were much better. Both curves were fatter in the lower rpm ranges where it will improve the drive off corners, and both curves were flatter as well. Peak horsepower was up 2% from 318 to 324 horsepower and peak torque was up 5% from 320 lb/ft to 335 lb/ft. In the heart of the curves, these numbers were even more impressive. At 4,500 rpm, torque was up 7% from 298 lb/ft to 319 lb/ft. At 5,500 rpm, horsepower was up 6% from 302 to 320 horsepower. Most engine builders will take full advantage of the coating by making jetting (or computer), timing, and lighter weight oil for maximum power gains. However for this test, we wanted to document and publish the gains that are achieved if the only modification was coating the engine. If the proper tuning adjustments were made to take full advantage of the coatings, these results would have been even more impressive.
This unbiased and independent test confirms exactly what a Swain Tech engineers would tell you to expect from a motor coated with Swain Tech’s coatings. It is important to remember that power gains are just part of the purpose of coating pistons and heads. In addition to making more power, parts are protected against burning, run cooler with more tensile strength and are protected from scuffing, seizing, galling and sticking. Rings, pins, rods and the entire bottom end will run cooler with coated pistons. Head and coolant temperatures are lowered with cylinder head coatings.

No other modification will offer more value for the investment. Is there any modification other than Swain Tech Coatings that will improve both power and durability at any price? For about $750 a typical V-8 can have pistons, heads and headers coated (the coatings that add the most power). A typical 6 cylinder would be about $550 to have pistons, heads and headers coated and a typical 4 cylinder would cost about $450. This is value that is hard to beat.
If you are involved in high performance motors, you owe it to yourself and/or your customers to have your parts coated with Swain’s thermal barrier and friction reducing coatings. The technology is proven and the benefits are unmatched by any other performance enhancement. Twenty years ago, coatings were new enough where a wait and see attitude may have been warranted. Now, a wait and see attitude will put you behind what the competition is doing.

Performance Improvements with Coatings Chart