Oil control is critical on the high-revving Nissan RB26DETT. The factory oil gallery orifice allows a relatively large volume of oil to reach the cylinder head. While this ensures lubrication, the excess flow can contribute to increased blow-by, oil consumption past the valve guides, reduced oil volume in the pan, and potential starvation at the crank journals—especially under sustained high RPM or cornering loads.
The Tomei Oil Gallery Orifice (part number TB2040-NS05A) addresses this by restricting the orifice diameter from the stock 2.0 mm to a carefully chosen 1.5 mm. Developed from Tomei’s experience with N1 endurance and drag racing engines, this simple modification maintains adequate lubrication to the camshafts and valvetrain while keeping more oil in the lower end of the engine. The result is improved oil stability, reduced oil-related issues, and better overall system balance.
Installation involves depressing the stock orifice and fitting the Tomei unit on top of it. At Terra Firma Automotive, we supply this genuine Tomei Oil Gallery Orifice as an inexpensive yet highly effective upgrade for Skyline GT-R R32, R33, and R34 builds. Whether you are refreshing a street engine or preparing a higher-output RB26, this orifice helps optimize oil distribution and protect critical components. A small part with meaningful benefits—available from Terra Firma Automotive.
- Genuine Tomei Oil Gallery Orifice
- Part Number: TB2040-NS05A
- Designed for Nissan RB26DETT
- Restricts oil flow from stock φ2.0 mm to φ1.5 mm
- Helps reduce excessive blow-by gas
- Minimizes oil consumption through valve guides
- Improves oil supply to crankshaft journals
- Helps maintain proper oil level in the pan under high G-forces
- Developed from Tomei N1 and drag racing experience
- Installs in conjunction with the stock orifice
- Simple and cost-effective reliability upgrade
- Suitable for street and performance RB26 builds
- Direct application for Skyline GT-R R32 / R33 / R34
- Precision-engineered oil control solution
- Available from Terra Firma Automotive
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