The Sanderson Limefire header offers a lakes style nostalgic look for outside chassis header needs, but it is the best header choice? Lakes style headers duplicate the header style used on '50's and 60's 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 this header was designed and used, the power output of the Flathead Ford and other engines that utilized this design wasn't very much compared to what we see today. Here lies part of the problem with this design and use on modern applications. The look is great, but it might not be best for many applications---aside from the look. It is here the customer must determine their need and requirements for the vehicle.
As we can clearly see in the images below, this beautiful roadster is using the Sanderson Limefire, Lakes Style header, and there is substantial discoloration of the ceramic coating on the tubes, and in a seemingly odd location. Why? Typically, when we see this type of discoloration, the first item to consider is the tuning of the engine. However, with regards to a Lakes Style header, there is more to the problem than tuning. Improper tuning can surely contribute to the discoloration.
The discoloration areas include the horn where the 2nd and 3rd tubes merge to about the intersection of the 4th tube, but also on 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 meet the horn. At this intersection, there is more exhaust gases than the header design can accommodate and is actually disrupting the 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 is causing the ceramic coating to break down.
The second issue on this specific vehicle "is" related to tuning. While the horn discoloration occurs more frequently on larger, more powerful, and more highway-driven applications using this header design, the discoloration up the 2nd, 3rd, and 4th tubes is not as common. Specifically, the "spotting" that looks like yellowish freckles on the 2nd and 3rd tubes is related to tuning issues. It is very possible that this application is running too rich or too lean, amplifying the breakdown of the header coating. The first step to determining proper tuning is to very correct ignition timing for the engine, ensure no vacuum leaks exist, 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, where measurement of the carbon monoxide percentage (CO%) will help determine proper tuning. Proper CO% exists between 1.2% and 2.5%. As the reading nears either of these values it 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 (on an application without catalytic converters) will begin to find our nostrils.
The third issue, more like a recommendation, relates to the under chassis exhaust system. We often recommend the Sanderson PowerCap inserts on Lakes Style and other outside chassis headers that will utilize an under chassis exhaust system. Helping to direct 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 utilization of an under chassis system, where some baffle inserts can contribute to excess restriction and increased heat in the horn, it is important to quickly address concerns regarding EGTs 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 flange design uses an 1/8" wide "smear" of silicone around each port---nothing more (except for some very specific applications). If properly installed, Sanderson Headers provide many years of leak-free service.
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 who builds these nostalgic designs), there isn't really much we can do. 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 is making, the more long highway trips the vehicle experiences, the more restrictive of a baffle or under chassis exhaust system, the more likely coating discoloration or potential damage to the header in these locations will occur. One option is to utilize a 4-into-1 lakes style design like the Sanderson Jayster or Jayster Full-Fender header designs. Having a 4-into-1 collector on the Jayster eliminates the problems discussed here with the 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 more directly related to the header design, and even if the header isn't coated damages will occur in the locations mentioned in this article. If the header was painted, these areas would be the first to peel. If it was 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 through our Helpdesk.
