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.
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.
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.”
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.
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.”
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.
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.
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.”
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.
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.