ARP recommends the use of main studs over bolts whenever possible for several key reasons. First is the ability to obtain more accurate torque readings because studs don’t “twist” into the block. All clamping forces are on one axis. By the same token, there is less force exerted on the block threads, which contributes to improved block life (very critical on aluminum blocks). Finally, there are factors of easier engine assembly and proper alignment of caps every time.
There are many important reasons to use ARP main stud kits, including the elimination of main cap walk and fretting, as well as protecting the threads in your engine block. All kits come complete with hardened parallel-ground washers and high quality nuts. Some applications have provisions for mounting windage trays and have specially designed standoff studs with serrated lock nuts to position the windage tray and lock it securely in place. The studs are manufactured from 8740 chrome molysteel, heat-treated in-house to 200,000 psi tensile strength, and precision J-form threads rolled after heat-treat to create a fastener that has threads 1000% stronger than others
TECH TIPS: MAIN STUD INSTALLATION
1. Clean and chase appropriate threads in block to ensure proper thread engagement and accurate torque readings.
2. All hardware (and caps) should be cleaned and inspected prior to installation,looking for any shipping damage or defects
3. Screw studs into block, finger tight ONLY. For permanent installation, apply Loc-tite (or similar adhesive) sparingly to threads. Be sure and install the caps promptly before the cement sets to prevent misalignment of studs in block.
4. Install main caps, checking for binding and misalignment. Lubricate threads, nuts and washers with oil or ARP moly assembly lubricant before installation. Note that torque specs will vary by lubricant. Moly lube is most consistent. Have block align honed.
5. Using the instructions provided with the studs, tighten the nuts to proper torque values three times. NOTE: If using Loc-Tite or similar cement, proper preload must be achieved prior to it setting up
