Adjuster - 5/16 Dia. Cup - 3/8-24 Thread

The Adjuster - 5/16 Dia. Cup - 3/8-24 Thread by T AND D MACHINE is a precision valve train component engineered for high-performance engine builders and serious automotive enthusiasts who demand exact control over valve lash and rocker arm geometry. This small but critical adjuster cup serves as the contact point between rocker arm tips and valve stems, allowing fine-tuning of valve clearance in systems that require micro-adjustments for optimal engine performance and longevity. Whether you're assembling a street engine, race motor, or restoring a classic with modern specifications, proper valve adjustment is non-negotiable for consistent power delivery and reliability.

The 5/16-inch diameter cup design provides a stable, wide contact surface that distributes load evenly across the valve stem tip, reducing stress concentration and wear. The 3/8-24 thread specification ensures precise fitment into rocker arm assemblies designed to accept this standard metric thread pitch, allowing repeatable adjustments without slippage or cross-threading. T AND D MACHINE's manufacturing tolerances ensure dimensional consistency across production runs, critical when building multiple engines or replacing worn components in a rebuild. The compact 2.85 x 0.65 x 5.3-inch profile minimizes valve cover intrusion while maintaining adequate material thickness for durability under high RPM and high-load conditions.

This adjuster cup is essential for builders working with aftermarket rocker arm systems, roller cam conversions, and any engine modification where valve lash must be set to specification rather than pre-set at the factory. Small-block and big-block enthusiasts, vintage car restorers, and performance engine shops rely on quality adjuster cups to achieve the exact clearance—typically 0.010–0.015 inches for hydraulic lifters—necessary for proper valve sealing and rocker arm longevity. Installation requires only a wrench and feeler gauge during final engine assembly or valvetrain service. For optimal results, always pair with compatible rocker arms and ensure threads are clean and dry before installation.