What - Engine Builder Magazine


That’s why you have to choose the gaskets you install very carefully. Gaskets have to fit correctly and have the durability to maintain a long lasting seal. Applications that are unusually demanding often require specially engineered gaskets that can handle higher pressures and temperatures without failing.

Advancements are constantly being made in gasket materials and designs, so to find out what some of the latest applications are we contacted various gasket manufacturers and suppliers. We also asked them for tips and suggestions on how to install their gaskets. Here’s what they had to say:

American Gasket

American Gasket is a supplier of gasket sets for mostly stock applications. “We’ve been in business for 32 years and specialize in rebuild kits and head sets for domestic, European and Asian engines,” says AG’s Eric McPherson. “We have over 1,000 different rebuilder kit numbers in stock, with availability and price being our primary focus.”

McPherson says he uses the same style of gaskets as the vehicle manufacturer for heads, manifolds and pan gaskets. “We have multi-layer steel (MLS) head gaskets for engines that came originally equipped with MLS, and composite gaskets for those that did not. We also have cork, composite and molded rubber manifold and pan gaskets.”

MacPherson’s advice for engine builders is to “know what you are working on.” Different engines often have different sealing requirements, so it is important to choose gaskets that have the correct materials and design for the application.

Cometic Gaskets

Kevyn Kistner of Cometic Gaskets says his company has revamped the embossing technique used to manufacture some of its MLS head gaskets for high performance applications.  The company has a variety of different MLS style head gaskets including standard 3-layer MLS gaskets, 3-layer Load Control Embossment (LCE) MLS gaskets, and 3-layer and 4-layer Multi Layer Stopper (MLX) MLS gaskets, which incorporate an integrated stopper layer for improved combustion chamber sealing.

The StreetPro product line includes various styles of MLS gaskets depending on the engine application, which Kistner says are superior to conventional composite fiber faced head gaskets that may require retorquing. The MLS head gaskets maintain their seal with less clamping load and produce less cylinder bore distortion, which reduces blowby and improves power.

One of the keys to installing MLS head gaskets, says Kistner, is to make sure the surface on the heads and block have a high quality finish, 50 Ra or less for Cometic MLS gaskets. The gaskets must also be installed dry with no sealer.  Also, if the engine has torque-to-yield (TTY) bolts, replace the original bolts with new ones. Reusing TTY bolts is not recommended because of the risk of breakage.

Kistner says Cometic has also recently introduced a new line of molded rubber valve cover gaskets that use nitrile rubber bonded over a steel spline. Applications include popular engines such as SB/BB Chevy, Ford and Hemi. Kistner says the advantage of this design is that the gasket won’t delaminate over time, and the steel spine prevents overtightening the gasket when it is installed. These gaskets must be installed dry and they are reusable.

Fel-Pro Gaskets

Federal Mogul’s Fel-Pro “PermaTorque” MLS head gaskets are now available for the popular LSX block from GM Performance.  The gaskets feature Fel-Pro’s exclusive “LaserWeld” stopper layer technology that has proved itself in NASCAR, NHRA and IHRA competition. The LaserWeld stopper layer is a steel ring .004? thick that is laser welded in the center layer of the MLS gasket.

Ron Rotunno, product manager for Fel-Pro Performance Gaskets says the LaserWeld stopper layer helps ensure maximum combustion sealing by precisely controlling the compression of each layer in the MLS gasket. This reduces head lift, prevents gasket damage and helps ensure a long lasting combustion seal under the most severe conditions. Rotunno says the new MLS gaskets can handle LSX engines that are producing up to 2,000 horsepower including naturally aspirated, turbocharged, supercharged and nitrous boosted engines.

“The trick to designing a performance MLS gasket is to know where the head is lifting and where bolt loading needs to be increased by the embossing to seal the cylinder.

“LaserWeld MLS gaskets are the new standard in Sprint Cup racing,” says Rotunno. He says the full hard stainless steel layers in the PermaTorque MLS head gaskets combined with precisely engineered sealing beads and advanced polymer coatings maintain contact pressure between the head and block in spite of the loads and motions that are taking place. Their PermaTorque MLS gasket technology helps engine builders address the challenges associated with rising combustion pressures, temperatures and increased casting motion in each new generation of high-output engines.

Rotunno said the blue coating Fel-Pro uses on their aftermarket MLS gaskets is capable of accommodating surface finishes in the 65 to 70 Ra range. On their MLS racing gaskets, a higher temperature FKM (Viton) coating is used, and requires a somewhat smoother surface finish of 45 to 50 Ra or less.

Another change that’s taking place is greater use of “press and place” floppy rubber oil pan, valve cover and some intake manifold gaskets. These are gaskets that fit into a recess machined into the sealing surface for the pan, cover or intake manifold gasket. Though such gaskets may appear to be reusable, reusing high mileage gaskets is not recommended because of changes that occur in the gasket materials over time.

For leak-prone carrier style OEM intake manifold gaskets, Fel-Pro has a line of “PermaDryPlus” intake gaskets that utilize an aluminized steel carrier.  The sealing surfaces also incorporate multiple beads or ridges to compensate for corrosion that may have taken place around coolant ports. The gaskets are use Viton sealing beads for maximum durability, and incorporate load stops to prevent overtightening the gaskets.

Rotunno cautions engine builders to never use RTV on molded rubber gaskets. The sealer can act like a lubricant and cause a pan or cover gasket to slip out of place. The only place where RTV should be applied is in corner areas if required to seal a joint.

Many one-piece rear crankshaft oil seals are made of PTFE (Teflon) for added durability. When replacing this type of crank seal, the seal should NOT be prelubed and must be installed dry.  This is because the seal is designed to transfer some material to the surface of the crank.  If this doesn’t happen, the seal may never mate properly with the crank and leak.

Another tip for engine builders offered by Rotunno is to brush off the black oxide coating on new cylinder heads bolts before installing the bolts.  The oxide coating increases drag on the bolt threads, and may thus reduce loading on the head gasket when the bolts are torqued to specifications.  Also, be sure to oil the threads and the underside of the bolt heads (or washers) when the bolts are installed.

Magnum Gaskets

Never heard of Magnum Gaskets?  For almost twenty years, Magnum’s parent company, Modern Silicone Technologies Inc. (MSI), has been a major supplier of hi-tech molded rubber, plastic and metal gaskets to aftermarket brands and OE service. The MSI triangle logo on their gaskets has been a familiar symbol of quality to their customers.The company is now going direct to the aftermarket with their Magnum brand name gaskets which are 90% American made, and cover most manifold, valve cover and oil pan gasket applications for domestic and import cars and light trucks.

Arnie Fox says the invisible difference between premium quality gaskets and those of lesser quality is the compression set of the synthetic rubber. “Compression set is how much a rubber seal loses its ability to push back against the sealing surfaces over a period of time. The smaller the number, the better.”

According to Fox, Magnum’s gaskets use high quality materials that resist taking a compression set. Matt Algate, Manager of Magnum’s Florida gasket molding facility explains, “Carefully selected and processed rubber compounds almost never exhibit more than 20% compression set in our tests, which are conducted according to ASTM standards. When we evaluate some competitors’ gaskets that have been sourced overseas, test results show a 40%-60% compression set are common with some results spiking much higher. We feel there is no way that those gaskets can maintain a tight seal for the same number of miles as premium quality gaskets.”

Magnum recently introduced valve cover gaskets for Ford-Navistar Power Stroke Diesel engines. These gaskets seal the valve covers and also provide a connection between the engine’s management system and the fuel injectors.  These gaskets feature nylon composite carriers with multiple locating tabs, precision molded silicone rubber sealing beads, and molded-in-place electrical connectors for the fuel injection wiring harness.

Magnum valve cover gaskets found in set VS25013 have two electrical connectors and fit most 1994-1997 Ford Power Stroke production. Magnum set VS25004 contains gaskets with one electrical connector and is designed for 1998-2003 Ford Power Stroke models. Magnum molded rubber gaskets should always be installed dry (no sealer).

MAHLE Clevite

“While we’ve been selling a perfectly adequate, stock replacement, head gasket for the 6.0L Ford, MAHLE Clevite has just introduced an enhanced head gasket for the 6.0L Ford Power Stroke engine for customers who have opted to increase the power output on their 6.0L,” says MAHLE’s Bill McKnight.

“Because of the additional demands on the head gasket when power is increased, we’ve stepped up with a gasket to handle that power. It compares perfectly in every aspect to the OEM piece except that it can handle aftermarket surface finishes that typically vary more that OE finishes. The new head gasket has a full face coating of the polymer needed to give a great fluid seal.”

McKnight says that Victor Reinz used a technology called “Wave-Stopper” to seal the Bugatti Veyron’s 1,000 hp engine, the world’s most powerful production car.  “The very same technology was used in our premium 1.05mm head gasket for the GM Duramax diesel engine. The concentric rings around the combustion chamber provide for more adaptable and more forgiving seal than a plain stopper used in most MLS gaskets.”

Mr. Gasket

A long familiar brand in the aftermarket, Mr. Gasket is now offering MLS cylinder head gaskets made of high-grade stainless steel. Each gasket layer/spacer is individually cut using a state-of-the-art laser cutting process to achieve precision tolerances.

Dave Muzic says Mr. Gasket uses a unique soft radius head gasket embossment formation process to optimize the embossment radius in critical areas. This reduces stress points, enhances gasket conformability, provides uniform clamp load distribution across the engine block deck, resulting in superior wet-out (embossment surface contact area) between engine block and cylinder head.

Muzic says all head gasket layers/spacers go through an additional stress relieving process to significantly reduce forming induced stress. The advantages of doing this are reduced brittleness in the material, increased flexibility and deformation retention. It also relaxes critical stress points in the head gasket sealing embossments. This stabilizes the gasket for reduced cylinder bore distortion and improved combustion seal in extreme pressure applications such as supercharged and turbocharged engines.

Mr. Gasket’s proprietary polymer coating is applied after the stress relieving process and ensures uniform coverage of the outer gasket layers providing no break in the coating. A typical MLS head gasket requires a smoother (30 Ra) surface finish than composite head gaskets. But the coating on Mr. Gasket’s MLS gaskets can seal a surface finish that is twice as rough (60 Ra).  The head gaskets also come with a lifetime warranty.

Pro Seal Gaskets

Better known for their pistons, JE Pistons has launched a new line of Pro Seal MLS head gaskets. Sean Crawford says customers have been asking for head gaskets, so the company decided to launch a line of head gaskets to complement their pistons.

“Any time you are pulling an engine apart, you are going to need a head gasket.  So we are now offering 3-layer and 4-layer MLS head gaskets for popular engine applications including SB/BB Chevy, Ford, Chevy LS, sport compacts and powersports,” says Crawford.

The Pro Seal MLS gaskets are stainless steel and are fully embossed before they are tempered and coated with a proprietary 4-step coating process.  One of the coating layers is Viton, and the top layer is silicone to prevent oil and coolant leaks.Cometic has revamped embossing techniques for MLS gaskets such as this Subaru application."Today</p

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