ARP GM/ Duramax 2001-2005 6.6L LB7/LLY (main stud kit)
ARP is the undisputed world leader in automotive fasteners. They manufacture every fastener, bolt and nut that the world's top engine and chassis builders rely on in house. ARP engineers ensure that every piece will outperform any other fastener on the market today. That's why so many top engine builders rely on ARP racing products to hold their engines together. To overcome head gasket failures that can occur in diesel engines employed in truck and RV applications, industry leader ARP has introduced extra heavy-duty head studs for the popular Ford, Dodge and GM power plants. These ARP studs are rated at 220,000 psi tensile strength, and provide the clamping force required to keep cylinder heads from lifting due to higher combustion pressures. The studs are manufactured in ARP's Santa Paula, CA plant from proprietary ARP 2000 material, with threads rolled after heat-treat to provide optimum fatigue strength. They are centerless ground to assure perfect concentricity. The ends of the studs are broached to facilitate easy installation. This feature also enables the cylinder head to be removed in tight quarters. Also included in each kit are heat-treated, chrome-moly steel 12-point nuts and parallel-ground washers. They are black oxide finished for extra durability. You should know that ARP® uses a premium grade 8740 alloy that is rated far superior to "aircraft" quality. Then, each stud is precisely heat-treated to 200,000 psi. Following heat treat, each stud is centerless ground to make it as close to perfectly concentric as possible. This procedure involves about ten very slight cuts and results in an exceptionally straight part. It's important to note that lesser quality studs are not even centerless ground, the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine). Because ARP® studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads literally glide into position and are perfectly aligned, something that won't happen with inferior quality head studs. ARP® studs are thread rolled after heat-treat, which gives them about 1000% (that's ten times) better fatigue strength than those studs that are threaded prior to heat-treat. You will also note that ARP® offers specially undercut studs for several engines. This procedure (done only to the shorter studs) more equalizes the "stretch" of both studs, which makes for a more consistent clamping force, one that compensates for head gasket compression when the head is installed. This helps prevent blown head gaskets, and assures optimum sealing! Premium parallel ground washers are also included with each kit.
TECH TIPS: HEAD STUD INSTALLATIONS Clean and chase all bolt threads in block to ensure proper thread engagement and accurate torque readings. All hardware should be cleaned and inspected for possible shipping damage prior to installation. Since most studs extend into the water jacket, coat threads with ARP thread sealer and screw in hand tight ONLY. Install gasket and head, then lubricate washers and nuts with oil or ARP moly assembly lubricant prior to their installation. Following the engine manufacturer's torque pattern, torque each stud nut three times to recommended values found in the general fastener chart below. NOTE: To ensure positive sealing of "wet" head studs, a hardening or semi-hardening sealant, such as Loc-Tite or Permatex, etc. should be used. Some engine builders employ a sealer in the coolant, such as Aluma-Seal, Silver Seal or K&W sealer, etc. You may also use high temperature RTV silicone. Whatever product is used, it is imperative that the cylinder head is installed and torqued to proper levels BEFORE THE SEALANT HAS CURED! Torque w/30-Wt Oil Torque w/ARP Moly-Lube 1/4in. stud 12-15 10-12 5/16in. stud 25-32 20-25 3/8in. stud 45-56 35-44 7/16in. stud 71-89 56-70 1/2in. stud 108-135 84-105 9/16in. stud 156-195 122-152 5/8in. stud 214-268 167-208 6mm stud 10 9 8mm stud 25-32 20-25 10mm stud 54-68 42-53 11mm stud 80-100 63-79 12mm stud 97-122 77-96