On Lock Down With Stage 8 Locking Fasteners

Gasket technology has come a long way since the days of the old paper units. The multi-layer steel (MLS) exhaust gaskets, like those used on the LS engine, seal much better due to their design. Some people even reuse them with success, though it’s not recommended. However, even though these gaskets are fantastic and far superior to their predecessors, they can still have issues, which is not the gasket’s fault, but rather, due to the hardware and vibration. 

It’s not uncommon for a bolt to back off with vibration, causing an annoying exhaust leak. If you’ve never suffered from one of these leaks, believe us when we say it will undoubtedly get your attention with an annoying tick that can sound like valvetrain issues. While people have tried things like lock washers, thread sealant, and even overtightening the hardware to keep exhaust manifolds secure, it will eventually fail. Fortunately, Stage 8 Locking Fasteners has developed a unique hardware system that makes it impossible for a bolt to loosen up. 

Since we are not interested in fighting exhaust leaks on our turbocharged LS, we ordered a set of bolts for the exhaust manifolds (PN 8900), wastegate (PN 3901), and nuts for the turbocharger (PN 3951).

Lock It Down

We talked to Bruce Bennett, Owner of Stage 8 Locking Fasteners, to get an inside look at their design, which originated from an unusual situation. Bennett owned a motorcycle, and after having a problem, he came up with the idea for his fasteners. Bennett said, “Stage 8 Locking Fasteners started 35 years ago after I installed a new pipe on my Harley, which fell off the same day. At that point, I started thinking. There’s got to be a better way.”

How It Works

Stage 8’s product takes a simplistic approach to a difficult problem with a unique three-piece design. Its patented products ensure security and include a custom aircraft-quality grade 8 – 4130-alloy steel bolt with a nickel finish, 5052-H32 polished aluminum or stainless steel retainer, and a spring steel C-clip that’s plated with Duplex nickel finish. With the bolt tight and the retainer in place, it’s impossible for the bolt to move.

You’re going to get a gasket leak anytime a bolt backs off a 1/4-turn, and I don’t care what type of gasket it is. If it backs out, it’s only going to get worse from there. The secret is never to allow the bolt to start backing off. If it can’t move, it’s going to keep the clamp load.

In the above image, you can see the bolt, retainer, and C-clip. You will also notice the Allen slot in the top of the bolt which allows access in tight spaces that you might not be able to get a wrench in.

Stage 8 vs. Thread Locking Compound

You may be thinking, “Why can’t you use a thread locking compound?” And that’s a valid question, because it holds up pretty well in most conditions. However, Bennett said, “A thread locker glues the threads on the bolt to the threads in the hole. While they have a purpose, they don’t work well in high heat, motion, and vibration. When you get all three of these elements working together, the bolt can only go one way; it will loosen. With the Stage 8 locking design, this is never a problem because the bolt can’t move. After you get the bolt tight, you will then place the retainer on the bolt. This retainer is like leaving a wrench on there all of the time.”

Under Pressure

Stage 8 offers hardware kits for all types of applications. And while headers and exhaust manifold hardware is a critical piece of the puzzle, a blown exhaust gasket on a turbo header or manifold is not only annoying; it can cost you power. As you may know, turbos are fueled by the energy of spent exhaust gasses coming out of the combustion chamber. If a turbo, wastegate, or turbo manifold has an exhaust leak, energy escapes and decreases the turbo performance. With Stage 8, you will never have to worry about the fasteners coming loose, ever.

Stage 8 uses aluminum retainers for headers because they don’t get that hot, only 400-500 degrees. Stainless steel is utilized for turbo applications because it can hit 1,200 to 1,400 degrees, which would melt aluminum.

Since we are not interested in fighting exhaust leaks on our turbocharged LS, we ordered a set of bolts for the exhaust manifolds (PN 8900), wastegate (PN 3901), and nuts for the turbocharger (PN 3951). 

Stage 8 Hardware Installation

The installation of this product is straightforward, but there are some things you need to know. “We recommend using anti-seize on the manifold bolts and then torque them down to the manufacturer’s advised torque specifications,” Bennett explains. “Also, there’s no need to overtighten for additional clamping force; the bolt can’t go anywhere.”

Make sure and use anti-seize and the factory torque specs when installing the new hardware.

First, we applied Anti-Seize to the bolts and then threaded them into our LS heads by hand before torquing them to 18 ft-lb. After the bolts were torqued to spec, we installed the retainers. These pieces have teeth that will lock down the bolt, keeping it eternally tight. We then snapped the C-clip in the groove on the bolt’s head with the retainer in place to secure the assembly. 

Stage 8 does include four extra retainers that have a bend in them. These are used when there’s no primary tube available and are used to clamp on the exhaust manifold or header flange.

The Stage 8 locking nuts were just as easy to install as the exhaust manifold hardware. We removed the standard nuts, replaced them with Stage 8’s, and popped on the retainer and the C-clip. 

Here’s a look at the turbo secured to the flange with the Stage 8 nut kit. This is an excellent option for those that don’t have room for a bolt.

Up to this point, the installation had gone smoothly with only the wastegate left. We removed the bolts from the wastegate to find that they were already loose from vibration. With the hardware removed, we quickly realized we had another problem. There was not enough clearance between the retainer and the body of the wastegate. So we asked Mr. Bennett about our little dilemma. He said, “Since all of our turbo hardware is made out of stainless steel, you can cut it or grind it down to make it work. We even recommend cutting the bar in some cases, so it’s shaped like a flare nut wrench for a really tight spot.”

Since the tab was too long to fit on our wastegate, we simply cut it down so it would fit.

With the stainless steel retainer in a vice, we cut the end of the tab off with a cutoff wheel. We then massaged it down on a belt sander until we were happy with the fitment on the wastegate. From there, we dropped the retainers on the bolts and once again snapped on the C-clip.

Even though our wastegate bolts were initially loose, there’s no way for them to back off now with the Stage 8 fasteners in place.

Conclusion

Today you can find Stage 8’s hardware all across the globe and even beyond. “Our products are used in all kinds of industries, including NASCAR, earth-moving equipment, railroad locomotives, trucking industry, off-road vehicles, and military vehicles…and that’s not all,” Bennett said, “Our claim to fame is the use of our fasteners on the robotic arm on the Space Station. They came to us because the bolts came loose on a $4,000,000 camera, which was lost.” We figure if the Stage 8 bolts and hardware are good enough for NASA, they are good enough for our junkyard LS engine. And fortunately, we didn’t even have to deal with all of that government paperwork to get them to our doorstep.

 

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About the author

Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
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