ARP Main Stud Kit – Nissan SR20DET | 8740 Chrome Moly | 190,000 PSI | 202-5402

The ARP 202-5402 replaces the factory SR20DET main bearing cap bolts with precision-engineered 8740 chrome moly studs heat-treated to 190,000 PSI tensile strength — delivering superior clamping force, more consistent torque, and improved main bearing cap alignment for any high-performance or high-boost SR20DET build. A foundational component for any serious SR20DET engine rebuild.

Why Studs Over Factory Bolts

When a bolt is torqued, it simultaneously stretches and rotates — the rotational friction consumes a portion of the applied torque, making precise, consistent clamping force difficult to achieve. A stud is installed into the block without rotation and stays stationary while the nut is torqued, so all of the applied torque goes directly into stretching the stud and clamping the bearing cap. The result is more accurate, more consistent clamping force at every main cap position. Studs also guide the main bearing caps into precise alignment as they slide over the fixed studs before the nuts are torqued — critical for maintaining correct main bearing clearances and ensuring the crankshaft runs true.

Key Features

• 8740 Chrome Moly Steel – 190,000 PSI: Significantly stronger than factory fastener material — allows the stud to be torqued to a higher clamping load without yielding, providing greater main bearing cap clamping force than factory bolts can achieve. Essential for high-boost SR20DET builds where cylinder pressure loads the main caps well beyond the stock design envelope
• Thread Rolled After Heat Treatment: ARP rolls the threads after heat treatment, not before — inducing compressive residual stresses at the thread roots that must be overcome before fatigue damage can begin. This vastly improves fatigue life compared to conventionally manufactured fasteners, critical in a high-boost engine where the main studs experience repeated high-amplitude loading
• Precision Parallel Ground Washers Included: Ensures consistent load distribution under the nuts across all main cap positions
• Exact Tolerances for Bearing Cap Alignment: Guides main bearing caps into correct position before torquing — maintains proper bearing clearances and crankshaft alignment

Fitment

• Nissan SR20DET — All variants (S13, S14, S15, 180SX RS13/RPS13, FWD)
• Nissan 240SX S13 / S14 — SR20DET swap applications

Specifications

• Brand: ARP
• Part Number: 202-5402
• Material: 8740 Chrome Moly Steel
• Tensile Strength: 190,000 PSI
• Thread Process: Rolled after heat treatment
• Includes: Studs, ARP nuts, parallel ground washers
• Application: Nissan SR20DET

Installation Notes: Engine disassembly is required to access the main bearing caps — professional installation by an experienced engine builder is strongly recommended. Clean all stud holes in the block thoroughly before installation; debris in blind holes causes inaccurate torque readings. Install studs finger-tight into the block only — do not use an impact wrench. Use ARP Ultra-Torque assembly lubricant on stud threads and under nut faces — ARP’s torque specifications are developed and validated using Ultra-Torque, and using a different lubricant (engine oil, anti-seize, or dry) will result in incorrect actual clamping force for the specified torque value. Ultra-Torque is sold separately and should be ordered alongside this kit. Verify main bearing clearances after installation.