Boundary LS9-OPG-SUMPROTOR-M Billet Sump Rotor Oil Pump Gear for LS9 with MartenWear Treatment

The Boundary LS9-OPG-SUMPROTOR-M is a billet Chromoly sump rotor oil pump gear engineered as a high-performance replacement for the OEM sintered gear in the LS9 dry sump oiling system. This variant includes Boundary's proprietary MartenWear heat treatment — a second-stage, in-house surface hardening process that delivers ultra-long wear and debris-resistant surfaces for the most demanding race and high-horsepower applications.

Manufactured 100% in Boundary's Dallas, Texas facility, each gear begins as a quenched-and-tempered Chromoly billet that is then precision CNC-machined and finished using Boundary's ColdFlow mirror-finishing process. The result is a surface-hardened, mirror-finished gear with an indestructible core — purpose-built to outlast and outperform OEM powdered-metal components under extreme boost and sustained high-RPM conditions.

Key Features:

• Billet Chromoly construction — eliminates OEM sintered/powdered-metal gear failure
• MartenWear Treatment — second-stage heat treatment for maximum wear and debris resistance
• ColdFlow surface hardening and mirror finish for reduced friction and superior fitment
• Surface ground gears machined in matched sets (inner and outer)
• Race-inspired gerotor design for optimized oil flow and structural strength
• Proven stable beyond 9,000 RPM and validated in applications exceeding 2,000 whp
• Each set hand-inspected, machine-inspected, and hardness-tested with a Blueprinting Report included
• 100% manufactured in the USA (Dallas, Texas)

The LS9-OPG-SUMPROTOR-M is the sump rotor component of Boundary's LS9 billet oil pump gear system. GM OEM cross-reference part number: 12578147. For a complete upgrade, pair with the Boundary LS9-OPG-PRESSUREROTOR.