Top End Performance ARP Hardware ARP Main Cap Studs and Bolts (NOT Head Studs) for BMW X3 25 24 23 22 21 ARP AM Main Stud M10 1.5 M10 1.25, 4.600" Pegasus Auto Racing Supplies ARP 201 5000 main stud kit BMW E36, E46 M50, M52, S50US, S52US (8740 ARP Main Cap Studs M50 M52 S50 S52 Ireland Engineering Racing. This ARP Main Stud Kit is specifically engineered for use with BMW M10 B18 and M10 B20 engines. Upgrading from factory main bolts to ARP Main Studs is a simple, yet greatly beneficial upgrade. ARP Main Studs offer the following benefits: Uniform Clamping Force: ARP Main Studs provide a uniform clamping force that OEM bolts cannot. With the improved distribution of pressure across main bearing caps comes better, more precise crank alignment for stability and longevity. Improved Block Stability and Rigidity: ARP Main Studs improve block rigidity and therefore stability. This ensures maximum power transfer from the crank to the drivetrain, which in turn ensures: Improved Throttle Response Greater Horsepower Higher Torque Output Prevent Main Cap Walk: This occurs as main caps shift and move out of position, which can cause crank and engine damage Reduced Risk of Fastener Stretching: Under high RPM applications and high loads, factory main bolts are prone to stretching and deforming. ARP uses advanced manufacturing techniques and high quality materials for hardware that is much less prone to deformation under load. Safeguard Engine Block Threads: Because ARP Main Studs have unmatched tensile strength, they are much less likely to deform or strip block threads under high loads. Additionally, ARPs precision machining and manufacturing ensures that stud threads are both highly accurate and consistent. 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 BMW M10B18 Applications: BMW 02 Series 1971 1975 1802 BMW 3 Series 1975 1983 E21 316 318 1982 1987 E30 316 318i BMW 5 Series 1972 1977 E12 518 BMW M10B20 Applications: BMW New Class Series 1966 1972 2000 2000Tii 1973 1974 2000 Turbo BMW 3 Series 1975 1983 E21 320 320i