If you want to see a customer really blow a gasket, try blowing a gasket job. A flaw in a paint job brings complaints. But a flawed engine or intake manifold job will result in a big-time loss of credibility with customers, not to mention a time-consuming make-good.

Gaskets are used anywhere a positive seal is needed between parts of a system. In today's market, however, there are a number of newer materials and gasket formulations that make the job both easier to do and more reliable for the driver.

Many concerns with traditional gasketing materials are eliminated with the newer chemical gaskets. One such material is The Right Stuff from Permatex/Loctite Corp., Rocky Hill, Conn. An elastomeric material, it is applied from a pressurized can (much as one would dispense whipped cream for a sundae). The material, which is a proprietary formula, forms a bead around the surface.

"It can be used essentially anywhere on the auto except where gasoline would come in contact with it," says Bob Harmacek, manager of fleet testing and product reliability for Loctite. That includes valve covers, oil pans, thermostat housings and rear seals. It is sensor-safe and remains effective at 550º F continuous and 600º F intermittent temperatures.

Harmacek talks about install-and-go handling: "Just put the car back together and take off," he says. With over 1.5 million miles of testing, mainly in police cars and taxis, he has yet to have a failure. He notes that the most difficult area is the thermostat housing, mainly due to the combination of temperature and pressure.

There are also other gasket applications where temperature plays a role.

Aluminum Engines
Don't be in a hurry to take aluminum engines apart. It is important to allow any aluminum engine or heads to cool completely before disassembling them. The risk of warping the metal is greatly increased if the head is removed or the block is taken apart while it is still hot.

Sometimes a technician may notice an indentation around the head of an aluminum engine, generally following the location of a gasket that was just removed. According to Tim Lis, gasket product manager for Mr. Gasket, Cleveland, Ohio, this may be due to the old gasket having a wire frame around it. "The wiring on the gasket is harder than the aluminum head or block and it wears away the aluminum," he explains. As a result, this condition may require further milling of the heads to assure the new gasket can give a proper seal.

Loctite's Harmacek says that a squeeze-on material like The Right Stuff will fill in imperfections in the metal, typically a problem on cast aluminum engines. "When heated, engine fluids are reduced in viscosity so they flow to the point of least resistance," he said. "Chemical gaskets fill in surface imperfections better." He notes it is a problem many technicians report with the 2.5 liter Chevy 6-cylinder engine.

Mr. Gasket produces its Ultra-Seal head gasket with Grafoil core, designed to provide maximum sealing on both cast iron and aluminum engines used under tough conditions such as racing. Grafoil is a flexible, non-asbestos material that remains stable at temperatures over 1,000º F. It offers excellent resilience, compressibility and high-temperature endurance. It will not creep, cold-flow, become brittle or brinell (indent engine blocks).

Actually, it is the lighter engines that gave rise to another technology making its way to shops --- multi-layered steel head gaskets. According to Mike O'Brien, product engineer with Fel-Pro Inc., Skokie, Ill., the move to multi-layered steel is being driven by OEMs who are using the materials in their new cars. The Dodge Viper is a good example. The gaskets have almost no mass to them. That made it difficult to get a good seal with ordinary composition gaskets, O'Brien notes. Instead, they went to multi-layered steel. He predicts a lot more molded rubber on both plastic and steel carriers will turn up in shops across the country.

"You can't design old gasket technology for new engines," he says. "You have to use the new materials. But we are finding the new technology can do wonders on old problems." One example would be taking care of the valve cover problems on some older GM models. The new multi-layered gaskets work wonders for those applications. Whether dealing with a high-performance engine or a street car, proper head gasket installation is important.

In addition to chemical-free sealing, Fel-Pro's PermaDryPlus line offers another advantage --- it is all but impossible to over-torque them on installation. Built-in torque limiters encircle the bolt holes ensuring that the sealing head will not split. The company says the gaskets last up to five times longer than other gaskets.

Head Gaskets
Re-tap and thoroughly clean all head bolt/stud threaded holes. If existing bolts or studs are being reused, clean the threads and lightly lubricate them to ensure accurate torque readings. Lis notes that torque specifications can vary with the type of lubrication used.

Specific models often require specific solutions. Honda Civics built between 1975 and 1987 often develop hot spots between the No. 2 and No. 3 cylinder. This can lead to head gasket deterioration and failure, which shows up in compression loss, coolant leakage, and eventually combustion transfer into the coolant passages.

"Curing this problem is not simply a matter of refacing the heads and bolting the engine back together with another head gasket --- a special gasket is required to counteract the hot spots," according to Tim Golema, service engineer for Victor Reinz, Toledo, Ohio. They have developed a new design graphite-faced head gasket to handle the problem. The P/N 3782 incorporates increased flange width and thickness. This provides greater flange load and distributes the load over a greater area, minimizing the effects of hot spots.

The company also offers a new Nitroseal gasket for the Ford 4.6 liter V-8. The gaskets feature graphite facing combined onto a perforated steel core. "These gaskets bolt right up with the same bolt load as the metal gaskets, and the lubricity of the graphite facing allows the engine mating surface to be in the 20 to 50 micro/inch Ra range, instead of the 9 to 13 micro/inch Ra range for the all-metal gaskets," Golema says.

Attaching the proper clamp load is one of the most important steps to assure a complete, successful seal. After installing the head gasket and cylinder head, be sure to tighten all bolts following the manufacturer's recommended torque sequence. It is surprising how many technicians will tighten the corners and then the middles, or will follow the same torquing sequence on every job, since not all manufacturers follow the same recommendations.

Some gaskets, like the PermaDryPlus, require no chemical adhesives. The silicone sealing bead constantly presses against the sealing surface, forming a tight barrier that keeps
oil from seeping across the gasket surface.

It should take at least three rounds of tightening with the torque wrench before the job is considered finished. Harmacek says torquing with chemical gaskets should be done in exactly the same order, and to the same degree of tightness, as with ordinary gaskets.

Mr. Gasket recommends the use of a product like Ultra-Seal hardened washers to further reduce friction and increase torque accuracy. Keep in mind, too, that several auto manufacturers recommend head bolts be retightened after a certain amount of operation.

The multi-layered steel head gaskets, originally developed for the Japanese motorcycle industry's lightweight applications, usually have some layers that are embossed, others that are not. Mazda, Mitsubishi and the 2.2 liter Honda Accord use this material. "The castings themselves are lighter and bend and twist more easily. A stiff composition gasket can actually bend the metal castings," O'Brien says.

He warns technicians to hold close to machining tolerances. Most OEMs look for a 30 Ra (0.030 inch) tolerance. This is especially important on aluminum engines or with aluminum heads on a cast iron block. Cast on cast usually has sufficient rigidity that a composition gasket can do the job.

Intake Gaskets
Before assembling intake gaskets --- especially on performance engines --- be certain that the head and manifold mounting surfaces are parallel. Line up the head ports to match exactly the intake ports.

Cover the open areas inside the engine --- places like the lifter galley and the ports --- so dirt or litter does not get into the engine and damage the components.

If the engine is equipped with a valley pan type gasket, do not discard it. On most engines, this pan may need to be used to ensure proper oil drainage back to the crank case.

Lis notes that, on large port applications, the gasket wall between ports is quite narrow. Be sure the adhesive has cured before installing the intake manifold to avoid gasket shifting. To get optimum long-term sealing, he also warns against using any type of copper gasket sealer on intake gaskets.

On intake manifolds, the tightening sequence is unique to each engine. On GM's 1993 V-6 4.3 liter engine, the primary tightening sequence runs, from front left,
8-1-9-10-11-12; and from front right, 2-3-4-5-6-7. However, the final tightening goes in strict 1-6 order down the right side and 7-12 down the left. By the same token, the same year's V-8 PFI, found on Camaros, Caprices and Firebirds, runs 12-11-4-1-5-6 on the left side and 10-9-3-2-7-8 on the right. The bottom line is to check your Chilton or Mitchell guide before fixing each head gasket.

Valve Covers
If existing valve covers or the old oil pan are being reused, be sure to clean and de-gunk them before reinstalling them on the car. It is quite important to check for warped or bent flanges if the job is to be a success.

Oil residue should be cleaned off the valve covers or oil pan gasket flange surfaces. A thin coat of adhesive should be applied to hold the gaskets in place during install.

Should time permit, it is not a bad idea to put the cover or pan on a flat surface, gasket side down, and use a heavy weight on the top to apply pressure on the gasket, allowing the adhesive to dry overnight. This will also allow the gasket to be removed with the covers or pan, eliminating having to scrape the cylinder head or engine block if disassembly is required.

Do not over-tighten the mounting bolts as this can bend the flanges. Tighten evenly, using a criss-cross pattern.

The next generation of gaskets coming from Loctite Corp. will be an anaerobic gasket --- gaskets that cure in the absence of oxygen. According to Harmacek, these materials will dispense in a plastic tube for easy application.

Anaerobic gaskets will find use where machine flanges meet machine flanges and other internal uses.

Transmission Gaskets
Getting transmission gaskets to seat properly can be every bit as tricky as with other gaskets. Some dealers, for example AMC's Jeep-Eagle, recommend that no sealer be used on many of their models.

Others, like GM's 200C transmission, popular on late 1980s models, may have a self-aligning pan gasket. These gaskets have three or four smaller bolt holes in the corner of the gaskets to help align the gasket to the oil pan and hold the bolts in place while the pan is being installed.

When seating gaskets on automatic transmissions, which do not require any adhesive, try using a dab of petroleum jelly to hold the gasket in place over the oil pan screen.

Gasket Basics
No matter what the application, there are certain general procedures a technician should follow any time a gasket is being replaced. The specifics change depending on the different areas of the automobile a technician is working on.

First, the basics. One of the key requirements when rebuilding an engine is to keep everything as clean as possible --- this means both the gaskets themselves and the gasket mating surface on the engine parts. All surfaces must be free of dirt, water, oil or grease. Note that water can be just as much a problem as old adhesive material. Be sure to remove all of the old gasket material that may be sticking to the oil pan, cylinder heads or intake manifold. The traditional 3M wheel generally works well. For tougher jobs, many manufacturers, including Loctite, offer gasket-removal compounds that usually work in about 15 minutes.

The area should be free of burrs. Next, be sure the gasket mating surface is flat. There should not be any warpage in excess of 0.0025 inches to 0.003 inches in any direction. To check the cylinder block for warp, run a straight-edge across the gasket surface of the deck. Measure across the width and length at several points to get a good reading.

It is important to keep the gaskets themselves clean throughout the installation process. Gaskets should not be taken out of their packaging until they are ready to be installed. Of course, no gasket should ever be reused.

Curt Harler is a freelance writer based in Strongsville, Ohio.

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