B38 Main Stud Kit by ARP

The BMW B38 engine is compact, turbocharged, and capable of impressive performance, but its factory main bolts are a weak point when power levels increase. The ARP Main Stud Kit upgrades your B38 engine with race-proven studs, providing superior clamping force, block stability, and protection under extreme conditions. Key Benefits of ARP Main Studs for the B38: Uniform Clamping Force: Ensures even pressure across main bearing caps for precise crank alignment and long-term reliability Improved Block Stability & Rigidity: Maximizes power transfer, improves throttle response, increases horsepower and torque Prevents Main Cap Walk: Keeps main caps securely in place, protecting crankshaft and engine integrity Reduced Fastener Stretch: High-quality ARP studs resist deformation under high RPM and high-load applications Protects Engine Block Threads: Precision machining and unmatched tensile strength reduce risk of stripped or deformed threads Whether building a BMW i8, 118i, 218i, or MINI Cooper B38, ARP Main Studs provide the reinforcement your engine needs to handle boosted, high-RPM, and high-horsepower builds. This simple upgrade offers peace of mind and long-term durability for any B38 performance project. When opting for main studs instead of factory bolts, it's important to note that the engine builder should mic the bores. Using studs may require a line hone to ensure proper fitment and alignment. A line hone is a machining process that can be used to resize and reshape the main bearing bores, ensuring that they are perfectly round and concentric. This is crucial for ensuring proper oil clearance and preventing premature bearing wear. By mic'ing the bores and performing a line hone if necessary, engine builders can ensure that the main studs are installed correctly and that the engine will perform reliably and at its best. Installation Instructions:  To ensure accurate torque readings and proper thread engagement, thoroughly clean all threads in the engine block. If necessary, use an ARP chaser to chase the threads. Before installing any hardware, carefully inspect and clean it for defects, shipping damage, and proper fit, length, and dimension. Gently screw the main studs into the engine block by hand until they are snug. Install the main caps, checking for any binding or misalignment. Apply ARP Ultra-torque fastener assembly lubricant to the threads of the studs, nuts, and washers. Install the washers and nuts onto the studs and tighten them by hand. It is highly recommended to use the ARP Ultra-torque fastener assembly lubricant provided with the kit, as it provides consistent clamping force and reduces friction on the studs. Do not use motor oil or other low-quality lubricants. PRELOAD (TORQUE) RECOMMENDATIONS 7. Following the manufacturers recommended torque sequence tighten the nuts steps 1-3 Step 1: Tighten to 20 ft-lbs. Step 2: Tighten to 40 ft-lbs. Step 3: Tighten to 60 ft-lbs. with ARP Ultra-Torque fastener assembly lubricant