The Other Guys — We Talk To Cometic About Non-Head Gasket Tech

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The Other Guys — We Talk To Cometic About Non-Head Gasket Tech


Usually, when it comes to writing tech articles about gaskets, the focus is on head gaskets. Probably because they play such a critical role in the search for horsepower. However, the other gaskets in the engine play a critical role as well, receiving their own R&D and subsequent technological advancements.

While Cometic Gaskets has become synonymous with multi-layer steel head gaskets, which can withstand the most severe cylinder pressures generated, the engineering team has also realized the need for advancing the less critical gaskets, both for increased performance as well as additional longevity.

Gone are the days of buying a roll of gasket material and grabbing a ball-peen hammer to create intake and exhaust gaskets. Sure that is still an option, just like it’s an option to drill holes with a hand-cranked drill, but far more advanced options exist today. Whether you have a super common combination or a rare, one-off application, Cometic can combine both design and technology to ensure you have the best gasket possible for your application.

The OEM and performance aftermarket are constantly looking for ways to increase the engine’s efficiency, thereby increasing its output. Gasket technology is very much the same, as power increases, so does the need to seal it. – Micky Hale, Cometic Gaskets

The First Stop: Intake Gaskets

While intake gaskets might seem like a simple application, in reality, they not only respond well to advancements in technology, but have gotten so specialized, that different applications will prefer different materials and construction. “A blower or turbo engine, will need a reinforced material most times,” explains Micky Hale, of Cometic’s technical sales department. “If the manifold is coming on and off a lot, like a PRO Mod Nitrous engine, we have a different material we would use there.”

It’s not just the use that can alter the ideal composition of the gasket, either. “Some of the small-block Ford and Chevy engines have a very thin line between intake runners so we would look at that as well for a different direction,” says Hale. “We will most often use our “KF” Kevlar Fiber materials for most options and it works very well. But if it’s a specialty application, we also have the means to cover those as well.”

Cometic, largely known for its MLS head gaskets also makes every other type of engine gasket you can imagine, in a variety of materials, for the proper sealing in any scenario.

On the intake side, there has been a move to some integral-to-the-manifold O-ring type seals on the OEM side, leading some to wonder if the traditional intake gasket is bound for the fate of the Dodo bird. Not likely, Hale says. “Both the LS and the Gen-III Hemi utilize that type of pressed in place (PIP) seal. The elastomer molded part gets pressed into a receiving groove of a specific depth. By design, it’s not able to under or over-compress the seal, they work well and can be made from varying elastomer, durometer, and cross-sections to perform in a host of applications.”

However, Hale explains, the P-I-P seals aren’t the end-all, be-all of the intake gasket world. “A traditional style gasket can be used [in place of a P-I-P seal] for different reasons,” says Hale. “Maybe the customer needs to change the manifold placement so the ports line up better or maybe the port is too large, not leaving enough room for the receiving groove. Our traditional-style gaskets can be made with any port shape, and in multiple thicknesses.”

P-I-P intake gaskets are extremely popular right now and have a lot of benefits. However, Hale does point out that they aren’t the end-all-be-all of gasket technology.

Running It Out The Back: Exhaust Gaskets

At the other end of the combustion process, header gaskets have an arguably more difficult job to accomplish. While an intake gasket might need to withstand pressurization of the intake tract at least they do so at relatively normal temperatures. Exhaust gaskets, on the other hand, operate in four-digit temperatures and can be asked to seal pressures in excess of the ones an intake manifold sees in boosted applications.

To that end, it’s really not surprising that exhaust gaskets more closely resemble head gaskets than intake gaskets. “Even today OEMs utilize MLS technology for this interface,” says Hale. It’s the best choice for high temperatures and long service life. We offer a few different exhaust sealing solutions that all perform very well under an array of conditions. With today’s cars and trucks being in service much longer than ever before its paramount the exhaust gasket can go the distance.”

One of the features considered in the decision-making process of selecting the correct gasket is conformability. Ideally, you want the gasket to conform to any irregularities in the cylinder head and header flange surfaces, without giving up strength or heat tolerance.

Speaking of longevity, how many times have you seen a header gasket come off in pieces when you remove the manifold? In addition to sealing well, extended durability is now a critical feature demanded by the market. The first, most durable material should be familiar to you if you have ever seen an MLS head gasket. It’s composed of multiple layers of stainless steel, with embossing to act as a spring, ensuring consistent sealing.

However, while an amazing performer, MLS gaskets aren’t always the right call. “We utilize two other materials [for exhaust gaskets] called Armor and HTS Fiber. They are a sheet type material with slightly different performance attributes,” Hale says. “The Armor material is constructed from a high-temperature Vermiculite and fiber core with laminated carbon steel faces. It features a high-heat capability with little compressibility, and is typically used on turbo flanges, exhaust manifolds, heat shields, and header gaskets.”

MLS exhaust gaskets, like head gaskets, are very popular choices in both OEM and aftermarket applications, due to its long service life and exceptional sealing capabilities. But like a head gasket, the surfaces really need to be almost pristine for MLS gaskets to do their job.

Sometimes, the decreased compressibility of an MLS or Armor gaskets is a measurable detriment, and in those cases, the HTS Fiber gets the nod. “The HTS material is constructed from a reinforced graphite fiber facing that utilizes a stainless steel core,” Hale says. “The material’s high compressibility works very well on irregular flange surfaces, and the typical uses are similar, but the stainless-steel core makes it ideal for use in the marine industry at the cost of a slightly reduced heat capability.”

New and Exciting Horizons

One thing we wondered, is whether or not any of Cometic’s gaskets have achieved the apex as far as the technology in them. Afterall, we’re just talking about intake and exhaust gaskets here, right? Wrong. “I sure hope we haven’t reached peak performance in engine gaskets,” Hale says, emphatically. “It’s in our nature to always want more. The OEM and performance aftermarket are constantly looking for ways to increase the engine’s efficiency, thereby increasing its output. Gasket technology is very much the same, as power increases, so does the need to seal it.”

The beginning of a customer-requested application usually comes to Cometic in the form of a physical tracing of the required gaskets. Sometimes CAD data is submitted, which makes the next step a little easier.

We asked specifically about oil pan gaskets. After all, it really doesn’t get more “mundane” than an oil pan gasket, except for maybe a water pump gasket. “The materials and technology of oil pan gaskets have changed dramatically over time. Early on the go-to material was cork, as better materials became available they were used as cork substitute, providing improved sealing and better torque retention, to further increase sealing,” Hale explains.

“Encapsulated (rubber-molded) technology was implemented where they encapsulate a steel carrier to produce a one-piece part. That technology eliminates the need for any additional sealants. Then another variant of encapsulated called “edge-molded” was developed, whereby the elastomer seal is only applied to the edge instead of encapsulating the entire seal. The flat portion of the aluminum carrier is only responsible for limiting how much it can compress the edge molded bead.”

Even though you might think of a seal as mundane, doesn’t mean that Cometic isn’t actively working on improving it. “We are continually looking for new gasket technology. After all, that’s the fun part! I wouldn’t say any one gasket has more technology in it than the other,” contends Hale. “However, I would say each gasket has a different technology focus depending on the gasket application and gasket environment.”

Whether submitted as a tracing or as CAD data, Cometic engineers then create a “drawing” which the machines can translate into instructions to drive the various forms of material cutters.

To that end, the Cometic team first has to identify what they are sealing (combustion gasses, extremely thin or thick liquids), the operating environment, and how the gasket will be sealing. “For instance, with our automotive head gaskets, we focus on limiting gasket bore distortion, whereas, with our powersports engine case gaskets, we focus on limiting gasket weeping and crawl out,” reveals Hale.

“Each situation is very technical but very different. When limiting bore distortion, we are continually looking at gasket embossment technology and gasket materials. When limiting gasket weeping and crawl out, our focus is on the gasket material itself. What material is going to be rigid enough to keep its shape and not crawl out, but at the same time be soft enough to seal an imperfect surface without completely sticking to it? Two very technical gaskets, but in two very different ways.”

And then the finished product. While it may seem like a relatively simple process, that’s because the Cometic team has experience on their side, which often makes complicated tasks look easy.

Sometimes the motivation to design a new gasket comes from an external source, as opposed to something identified by the R&D team. “Some come directly from a customer for an application we currently don’t offer,” says Hale. “We receive from a sample and go from there with what material they want to use, intake port sizes, different water flow, etc. It can be anything sent in from a DXF file or a tracing on a piece of paper.”

With such an active R&D department and an immense amount of technology already in its catalog, it leaves one wondering what kind of advancements are on the horizon in the world of gasket technology. “Sometimes you have to look back to go forward. We are working on silicone beading, which is a very old gasket technology. Still, we are looking at using it in applications other than head gaskets, while also looking at improving the silicone’s chemical makeup for performance and production purposes,” says Hale.

As long as the market continues to evolve, so will Cometic’s designs. Whether it’s materials, design, or just applications, the R&D team always has work left to be done.

“Another example of gasket technology revival is in our “Spring Energized Gasket” head gasket line. Many years ago, we had a high-performance line of head gaskets that featured a gas-filled O-ring. As time went on, the gas-filled O-ring head gaskets faded, and we discontinued the line. The line of SEG head gaskets feature a spring-energized O-ring — taking inspiration from the gas-filled O-rings of years ago. We always have our eyes open for improvements in gasket technology, and sometimes, inspiration comes in unexpected places.”



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