Sanderson Limefire - Header Tech
The Sanderson Limefire header offers a lakes-style nostalgic look for outside chassis header needs, but is it the best header choice? Lakes-style headers replicate the header style used on '50s and '60s salt-flat racers, and the design is ridiculously simple. Each tube connects to a tapered horn, exiting just past the last cylinder and away from the body of the vehicle. It easily fit the applications of the time, wasn't too heavy, and provided considerably more flow than factory exhaust manifolds. If we consider the era in which this header was designed and used, the power output of the Flathead Ford and other engines that used this design was much lower than what we see today. Here lies part of the problem with this design and its use in modern engine applications.
The look of the Sanderson Limefire is great, but it might not be the best for many applications. It is here that the customer must determine their need and requirements for the vehicle.
We can clearly see in the images below that this beautiful yellow roadster is using the Sanderson Limefire, lakes-style header, and that there is substantial discoloration of the ceramic coating on the tubes in a seemingly odd location. Why? Typically, when we see this type of discoloration, the first thing to consider is engine tuning. However, regarding a Lakes Style header, there is more to the problem than just tuning. Improper tuning can surely contribute to the discoloration and breakdown of the thermal ceramic coating when exhaust gas temperatures (EGTs) exceed 1400°F.
The discoloration areas include the horn where the 2nd and 3rd tubes merge, extending to about the intersection of the 4th tube, and virtually the full length of tubes 2, 3, and 4. Then, the discoloration ends. What we're seeing here is two problems. The first problem is where the 2nd and 3rd tubes merge with the horn. At this intersection, there are more exhaust gases than the header design can accommodate, which is disrupting airflow from the 1st tube. The 4th tube is adding to the problems (even though the horn taper increases), effectively trapping the exhaust gas pulses in the middle of the horn. In simple terms, we have a sort of exhaust gas gridlock that is increasing heat in this region, and it is this increased heat (thermal restriction) and associated increase in exhaust gas temperatures (EGTs) that are partially contributing to a breakdown of the ceramic coating.
The second issue relates to component selection. Many builders appreciate the sound and shake provided by certain camshaft designs that are often too big for the application. Low-lift camshaft designs with a considerable amount of duration (valve opening time), narrow lobe centerlines, and considerable valve overlap (both intake and exhaust valves open at the same time) offer the rumble that many enthusiasts demand. However, these oversized camshafts can contribute to the tuning struggles and the premature degradation and failure of thermal ceramic header coatings. The more unburned fuel that enters the exhaust, the higher the EGTs.
The third issue on this specific vehicle is related to tuning. While the horn discoloration occurs more frequently on larger, more powerful, heavily cammed (valve opening overlap), and more highway-driven applications using this header design, the discoloration up the 2nd, 3rd, and 4th tubes is less common. Specifically, the 'spotting' that appears as yellowish freckles on the 2nd and 3rd tubes is due to tuning issues. It is possible that this application was running too rich or too lean for an extended period of time, which accelerated the breakdown of the header coating.
The first step in determining proper tuning is to verify and correct the engine's ignition timing, ensure there are no vacuum leaks, and then diagnose the fuel system for proper jetting and other factors. The use of a 4- or 5-gas analyzer can assist in this process. Measuring the carbon monoxide percentage (CO%), or unburned fuel value, in the exhaust helps determine proper tuning. The proper CO% range for a gasoline-powered classic (pre-1990s) engine is 1.2% to 2.2%. As the reading nears either of these values, the engine will begin to run poorly. As it nears 1.2%, the engine will start to 'hiss' somewhat (heard in the air intake/carburetor), and as it exceeds 2.2%, the smell of raw fuel (in an application without catalytic converters) will begin to reach our nostrils, and our eyes may start to burn.
Newer, modern engine designs operate more efficiently and produce considerably lower CO% values because the designs and fuel metering have substantially improved.
The fourth issue, more of a recommendation, concerns the under-chassis exhaust system. We often recommend the Sanderson PowerCap inserts for Lakes Style headers that use an under-chassis exhaust system. Directing the exhaust gases into the under-chassis piping can help reduce some of the problems we're seeing on this vehicle. Although the same problems can occur without an under-chassis system, where some baffle inserts can contribute to excessive restriction and increased heat in the horn, it is important to address EGT concerns as soon as they appear.
In addition, though not officially part of this specific article, the person who installed the headers in these images did not follow the installation instructions. We know this because we see gaskets installed between the cylinder heads and header flanges. Please follow the installation instructions to prevent sealing issues! Sanderson Headers' patented raised flange design uses a 1/8" wide 'smear' of high-temperature silicone around each port. If properly installed, Sanderson Headers provide many years of leak-free service.
The discoloration and breakdown of the thermal ceramic coating that occurs on the Limefire headers is directly related to one or more of these items:
- Engine power output
- Camshaft selection (overlap)
- Tuning (timing, fuel delivery)
- Header style
In conclusion, how do we prevent discoloration of our lakes-style headers? Unfortunately, if it comes to this style header (and Sanderson is not the only company that builds these nostalgic designs), component selection, tuning, and understanding the limitations of this design can reduce or prevent issues. We know that many customers want this style header on their vehicles, and why not, as shown in this example, they look great! The more horsepower the engine makes, the number and distance of long highway trips the vehicle experiences, and the more restrictive the baffle or under-chassis exhaust system, the more likely coating discoloration or potential damage to the header in these locations will occur.
One recommended option is to use a 4-into-1, lakes-style design, such as the Sanderson Jayster or Jayster Full-Fender header. Having a 4-into-1 collector on the Jayster eliminates the problems discussed here with the Limefire, horn-style lakes headers. The Jayster headers are available for most popular V8 engine applications, so if you don't see your engine listed on the Century Performance Center website, please contact us.
Please note: This article discusses the discoloration and breakdown of the ceramic coating on this style header. The problem is related to both the header design and the engine's power output and component selection. Even if the header isn't coated, damage may occur in the locations mentioned in this article. If the header were painted, these areas would be the first to peel. If it were a lower-quality header, the 2 and 3 intersection with the horn would be the first locations to crack or show signs of base material damage. The purpose here is to simply highlight why things occur. We're still fans of using lakes-style headers on many applications because of the 'look' they provide. It is the customer's / builder's / crafter's choice to decide what they want for their ride.
If you have additional questions about your application, installation, or other concerns, please contact us
Related Articles
Sanderson Header Warranty
Limited 5 Year General Warranty Sanderson Street Rod Headers strives to supply our customers with the highest quality parts and service available in the street rod industry. In keeping with this, we warrant and will repair or replace, at our option ...Headers and Starter Clearance
Starter clearance can pose a unique challenge for many header installations, especially when installing headers on a classic vehicle application. Just imagine how many times the starter may have been replaced on a 30+-year-old vehicle. Was the ...Basic Header Installation Procedure
Besides a few common tools, patience is the most important tool for installing a set of headers. Sanderson Headers are built by hand in the USA with the finest materials. When properly installed, Sanderson Headers will provide many years of ...Direct-Fit Headers
The Confusion of Header Terminology The questions "Are Sanderson headers direct-fit?" or "Do I need to modify my down pipes to connect to Sanderson headers?" are asked regularly, and the answers are simple. NO, Sanderson does not manufacture ...Exhaust Header Cleaning and Upkeep
Maintaining the Header Finish and Ensuring Longevity Exhaust headers are an investment in our vehicles. The installation of headers offers performance and efficiency gains, for a cost that is often substantial. In addition to making sure we select ...