KM 12 Valve Billet Tappet Cover (120510-2V2) for 1989-2002 Cummins 5.9L

KM 12 Valve Billet Tappet Cover (120510-2V2) for 1989–2002 Cummins 5.9L

Built for Modern 12-Valve Performance Builds

The Keating Machine KM 12 Valve Billet Tappet Cover (120510-2V2) is a precision-machined upgrade for 1989–2002 Cummins 5.9L 12-valve engines. Keating redesigned this cover in early 2018 to support modern valvetrain setups while improving durability and sealing over the factory stamped-steel design.

Keating machines each cover in-house from a solid 3/4-inch thick billet aluminum blank. As a result, the finished part delivers superior rigidity and eliminates the flex and oil seepage common with OEM tappet covers.

Increased Roller Lifter and Rocker Clearance

This updated design provides additional internal clearance for roller rocker arms and link-bar style roller lifters now used by many engine builders. That extra room supports aggressive valvetrain combinations without compromising oil control or fitment.

Because valvetrain setups vary, Keating recommends verifying clearance during installation, just as with any performance engine component.

Integrated Baffling and High-Flow Ventilation

The tappet cover now includes internal baffling to improve oil control and manage crankcase vapor movement. This becomes especially important in high-RPM or high-boost applications.

The design also features –12AN male O-ring boss breather ports, allowing high-flow crankcase ventilation. This setup works well with catch cans, external breathers, or custom ventilation systems.

Leak-Free O-Ring Sealing and Hardware Included

Instead of relying on a traditional gasket, Keating machines a precision O-ring groove into the cover. This design simplifies installation while delivering a consistent, leak-free seal against the engine block.

Each cover includes stainless steel mounting hardware for corrosion resistance and long-term serviceability.

Fitment Notes

• Fits 1989–2002 Cummins 5.9L 12-valve engines

• Does not fit common rail engines

• Designed for flat tappets and known roller lifter setups

• Clearance verification recommended for custom valvetrain combinations

Whether you’re building a performance street truck, competition engine, or high-quality custom setup, this billet tappet cover delivers strength, clearance, and clean engine-bay appearance in one proven package.