SUPER NUTS & BOLTS
A look at ARP head studs and what makes them better than stock
The first step to creating a successful business is to identify a public need. Then, you’ve got to fill it.
That’s exactly what racing enthusiast Gary Holzapfel did back in 1968 when he noticed friends and fellow racers succumbing to bolt-induced engine failure: He put his background in fastener manufacturing to use and developed a solution. Soon, Holzapfel began making race-quality fasteners with aerospace technology, and ARP was born.
All of ARP fastener manufacturing is done in-house at a Southern California facility. The process starts with wire coils and ends with fasteners, nuts and bolts that are superior to what is widely considered aircraft quality. ARP’S fasteners are built to withstand serious racing, have higher tensile strengths and can survive higher stresses than most aircraft fasteners will ever see.
ALL OF ARP FASTENER MANUFACTURING IS DONE IN-HOUSE AT A SOUTHERN CALIFORNIA FACILITY. THE PROCESS STARTS WITH WIRE COILS AND ENDS WITH FASTENERS, NUTS AND BOLTS THAT ARE SUPERIOR TO WHAT IS WIDELY CONSIDERED AIRCRAFT QUALITY.
The process is simple, but more precise than those used for the bolts you’d find at the hardware or aircraft surplus store. First, ARP works with their steel suppliers to get the best grades of steel. While steel essentially comes in four grades, ARP uses only the top two (aircraft grade steel is generally only a tier-two material—not up to ARP’S standards). The original line, still produced, is the ARP2000 line, and it exhibits a whopping 220,000psi tensile strength. But that isn’t even the peak strength of ARP products. The newest addition to the lineup, ARP’S Custom Age 625+ hardware, boasts an even-higher tensile strength of 260,000 psi—when your boost numbers are climbing, these head studs are a must!
When the steel arrives, it’s a coil of raw steel wire and looks like a round bar. This steel wire then undergoes one of two processes: cold or hot heading. Contrary to the name’s implication, cold heading is done at room temperature; meanwhile, hot heading is a tad more literal. (It’s not some angry guy yelling at the parts as they wiz down the line!) Instead, the steel is heated to a glowing state to facilitate the forming of complex shapes and/ or tougher-than-average (for ARP) alloys. This is just one of the many steps it takes to produce the studs, nuts and bolts that will keep your race engine alive—even under the most extreme conditions.
After forming the basic bolt, stud or nut, with threads, heads and body diameters to
suit the application, the stock is sent to ARP’S in-house heat-treat facility and then to shot peening. Heat-treating gives the bolts strength without brittleness, while shot peening further improves the strength and durability.
All ARP products are then random batch tested for quality. Once they’ve passed the grade, they’re packaged up and shipped out to motorsport enthusiasts around the world.
Yes, the race goes on—often because ARP helped keep the heads on and the rods spinning. UDBG
Each batch of ARP bolts is put through rigorous testing before being packaged for shipping. This Instron unit pulls the bolts apart and then registers the force needed to make them yield and break. Bolt stretch and other factors are checked here to ensure your bolts are perfect for your high-power needs.
Here you can see a coil feeding into a cold header machine. No additional heat is used in this process.
The cold heading process takes coil wire (L) and forms it into a basic bolt head (R). Four stations are needed to get the coil wire into the necessary form for the bolt making process.
Bolts are sent to the heat-treat ovens to get the correct hardness— not too soft and not too brittle. This Beavermatic is a hottie and turns soft steel into hard nuts and bolts.
Hot heading involves heating the steel blanks to a precise, red-hot temperature and then applying tons of pressure to form the heads. This process is used for more complicated bolt head designs.
ARP recently introduced their 625+ line of fasteners. Here you see a comparison of their ARP2000 and 625+ head stud kits for the Ford 6.0L. The 625+ studs are the shiny ones. However, the difference goes deeper than just the look: The ARP2000 parts are made from chrome-moly steel and have an impressive tensile strength of 220,000 psi. The Custom Age 625+ parts take it to the next level. They are made from a heat-treatable stainless steel and are rated at a minimum tensile strength of 260,00 psi, with higher numbers often seen in testing. If you’re going for Max Race power, the added clamping load the 625+ can provide is perfect. For more mild builds, the ARP2000 line is better than stock and more cost effective.
Here you see an ARP head stud kit being installed on a Ford 7.3L diesel.
ARP is constantly developing new products. We found this Cat I6 engine in their R&D shop being used to engineer another line of diesel engine upgrade assembly hardware.