CUMMINS 6.7L 09+UP 4.312'' TOP END GASKET KIT Cometic

Cometic - The benchmark for cylinder head gaskets

Since its inception, Cometic Gaskets has produced gaskets of the highest quality for the motorsport market. Cometic's attention to detail means that today they have taken over a large part of the market and have now become a well established brand.
To ensure that they supply the best gaskets to the broad market of engines, they use different materials. They always have a gasket to match, from the most advanced MLS(Multi Layer Steel) gaskets to synthetic blends such as Aramid-Fiber.

Cometic combines these advanced materials with the very latest manufacturing technology to produce the requirements set by the customers. Design engineers look at and analyze the various environments in which the gaskets are to be used. These analyzes are then used to determine which material is best suited for the purpose. This process allows them to produce some of the best gaskets on the market.

Made in Ohio

Cometic started in the Powersport category and then branched out in the major markets such as Muscle Cars, Sports Compacts, Marine and also Agriculture. Their state-of-the-art facility in Concord, Ohio which is a whopping 6500 square meters and includes a large R&D department, where new materials are tested daily to take their products to the next level.

Cometic's involvement in motorsports has led to many revolutionary discoveries that they then use on all their gaskets. Their involvement in racing in AMA, ARCA, Busch, IHRA, IRL, NASCAR and NHRA has allowed Cometic to test their gaskets in the most extreme conditions. This with unbeatable results!

Choosing the right gasket

The cylinder head gasket ensures that the surface between the block and the head is kept completely tight. To make the gasket more reliable and to make it hold properly, must the mounting surfaces be completely flat. Therefore, it is always recommended to smooth out unevenness both on the head and on the block.

Head gaskets are available in a variety of thicknesses and sizes. We recommend going for around 1.3mm in thickness to get a gasket that takes the uneveness of the head or block well without affecting the compression too much. However, if you need to flatten the head or the block, you can compensate for this with a thicker gasket.

Regarding Bore, we always recommend that you lay between 0.5-1mm above the bore off the cylinder. This is to avoid the risk of the gasket sticking into the combustion chamber.

MLS - Multi-Layer Steel

MLS is exactly what it sounds like, a multi-layer steel gasket. This type of gasket is by far the most common for engine builders as it effectively distributes the pressure over the entire contact surface. This means that you can seal the surface already at lower tightening torques.

The outer layers are coated with FKM (Viton), a temperature/chemical-resistant polymer and have a surface of PTFE (Teflon) which gives the gasket additional strength against corrosion.
Cometic recommends installing the gasket as is. In other words, no gluing or re-tightening is required for the sake of the gasket. However, we recommend to check the tightening torque of the cylinder head bolts. It's a simple assurance that you haven't missed anything!

MLX - Multi-Layer Extreme

MLX gaskets are built in the same way as MLS. Here, however, something called a Stopper has been integrated. It is a unique ring around the combustion chambers that further seals this surface.
It also moves much of the pressure to be around the combustion chambers instead of evenly distributed over the entire surface. This is to cope with extreme cylinder pressures.

Just like with the MLS gaskets, no gluing or tightening is required. However, we also recommend here that you check the tightening torque as an assurance.