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Affordable High-Temp Coatings for Exhaust-Systems

Story & Photos: Jim Clark (The Hot Rod MD)

ZyBar is a new product in a full line of underhood and under car thermal insulating coatings for the automotive aftermarket. It’s an economical alternative that outperforms conventional tapes, wraps, and ceramic or powder coatings.

It improves scavenging to increase horsepower and fuel economy (performance validated by 3rd-party dyno-testing). It is corrosion resistant, reduces radiant heat by over 90% and performs in 2000°+F temperatures.

ZyBar is extremely lightweight (.001-inch thickness) with an ultra-smooth finish and available in three colors: Bronze Satin, Midnight Black and Metallic Silver (cast).

Applying ZyBar is an easy four-step process. Begin by media blasting the part surfaces and wipe clean. Thoroughly stir/mix the coatings. Air-spray, wipe or dip a single, even coat. Then convection oven cure at 450°F for two hours, or air cure for a full 120-hours.

Application can be done by professionals or DIYers for about half the cost of other forms of temperature-resistant coatings. I still own a Ford project-van from the days when I was publishing Vans & Trucks Magazine. It now has an Edelbrock-Performer equipped high-performance 460-V8 in the engine bay. Vans can produce more heat in the interior due to the location of the engine that protrudes into the passenger compartment.

To reduce this heat transfer, I coated the exhaust manifolds and exhaust pipe with ZyBar thermal insulating coating. I was removing the engine to make some upgrades so the process was simplified. I performed most of the preparation but left the application to a professional because they have the paint booth and equipment needed to spray the parts. A professional can do this at a very reasonable price if you have everything ready beforehand.

However, it can be applied by the DIYer because there is no thinning (it’s sprayed right from the can after pouring through a filter into the gun). A cheap low-pressure spray gun and clean air supply is all that is needed.

I sandblasted the manifolds and exhaust pipe with garnet sand that is designed to metal etch (100-120 grit) in an inexpensive portable gravity-feed abrasive blaster.

Sources like Harbor Freight offer inexpensive blasters like this. If you do not have a compressor or place to do the blasting, a local automotive paint shop or powder coater should be able to blast a set of headers for you at about $30 to $50.

The outside of the manifolds is cleaned of all oil, grease or dirt before blasting to remove any mil scale, rust and surface contaminants. If the coating is to be applied to the inside of the system, blasting inside of each tube should be done for a minimum of at least 60 seconds while rotating the tube or opening, allowing the inside to be etched completely.

While cleaning the manifolds, I discovered that the right-side manifold had a crack all the way through to the inside. Forty years of service had taken its toll and it was not practical to try repairing it.

In today’s world of internet access, I was able to find a suitable replacement on e-bay that was originally on a ’75 Ford F-100 pickup. Many components are used on a variety of vehicles in a manufacturers lineup.

After the parts were cleaned of all contaminants, I masked off all surfaces that I did not want to be coated. Access to the inside of the passages must be left open if coating is to be applied there. Any areas that you do not want coated can be cleaned off with acetone before the coating has cured.

For the two manifolds and the exhaust pipe connecting the manifolds to the muffler, two 8-ounce cans of ZyBar (uncut, directly out of the can) was more than enough material to complete the job.

Parts were hung up to provide access to the parts from all angles. We enlisted the talents of Klaye Slack at Auto Matrixx Collision Services in St George, UT to apply the ZyBar coatings to our exhaust parts.

Use low pressure 30psi conventional spray paint equipment set to achieve a coating thickness of 1.5 – 1.75 mils. A fine nozzle tip size with the air pressure setting at approximately 28-30psi is recommended.

Keep the gun nozzle 3” to 6” from the surface of the part. Allow the coating to flash off and be dry to the touch.

The coating dries to the touch quite fast but needs to be handled carefully until the coating has cured. Air curing takes 5 days (120 hours), while convection oven curing (not your home oven) is done at 450°F for 120 minutes.

The finish is a bit fragile until it is cured, when it becomes very durable. Once it is placed into service, the heating of the part will likely cause the coating to smoke for a short period of time, a normal part of the final curing process.

The finished coating appears to be thin when compared to other coatings of this type but offers superior performance at about half the cost. If it is nicked or scraped inadvertently, the coating can be touched up because ZyBar is formulated to bond to itself.

The Midnight Black color used on the exhaust system works well on my Ford-Blue Edelbrock Performer-equipped 460-V8 that powers my ‘80s van. It enhances the appearance of the powerplant but is serving a more practical purpose by reducing the heat generated within the tight confines of the engine bay.

In summary, High-Temp coatings are very effective at controlling heat transfer in all types of vehicles but can be a bit expensive. ZyBar offers an alternative that performs as well or better at about half the cost.

ZyBar is DIY friendly and can be used to coat both the inside and outside of exhaust systems. This makes it more effective in the process of sending that heat out the tailpipe. It does require that the DIYer have some more advanced equipment and skills to successfully complete the application process themselves. I found that splitting the application process into separate steps allowed me to do the prep that I was comfortable with and inexpensively delegate other tasks to the pros.

ZyBar now offers an alternative product named ZyCor that is applied to the exterior only. It is much more user-friendly because it is supplied in spray-cans. Preparation is the same for both products but the application is simplified.

For those who wish to have the whole process done for them, ZyBar now has a service where you send your items to be coated to them in Olathe, KS (Kansas City) and they do it all. It is returned to you ready for installation.

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