Mazworx RB25 Block Stage 2.5

The Mazworx RB25 Block Stage 2.5 is a precision prepped engine block upgrade designed to support high-performance builds of up to 1200 horsepower. Crafted using advanced CNC machining and state-of-the-art equipment, this package is ideal for DIY engine builders looking to enhance their Nissan RB series engines with reliable and professional machining services.

Key Features

• Hot Tank Cleaning: Thorough cleaning process to remove oils and grime, preparing the block for further machining.
• Sand Blasting and Painting: Exterior sand blasting rejuvenates the block’s appearance, followed by a semi-gloss black paint finish for durability and aesthetics.
• 12mm Head Stud Machining: Upgrades the factory 11mm head studs to 12mm, allowing compatibility with RB26 head studs. Necessary machining for non-RB26 heads.
• Threaded and O-ringed Freeze Plugs: CNC machined freeze plug holes for installation of threaded and o-ringed plugs, preventing leaks and plug ejection under high boost conditions.
• Precision Cylinder Boring and Honing: Bores are machined on a 3-axis CNC for perfect centering, then honed with a Sunnen SV-10 diamond tooling system for an optimal cylinder finish.
• Oil Groove Machining: Adds an oil groove in the upper main journals to allow use of 5-hole main bearings, enhancing oil supply to mains and rods. This modification is CNC machined for accuracy.
• Main Stud Installation and Line Honing: ARP main studs are installed, followed by line honing to exact specifications for precise alignment.
• Deck Surfacing: Performed using a coated CBN cutter to ensure a flat and true deck surface.
• Oil Port Plug Removal and Cleaning: All oil port plugs are removed for thorough cleaning of oil galleys, followed by CNC machining to install Mazworx o-ring threaded plugs that ensure a reliable seal and ease of future maintenance.
• Torque Plate Honing: Utilizes a custom torque plate to simulate head bolt load during honing, maintaining cylinder true dimensional accuracy — especially important when installing sleeves. Optional for stock sleeve blocks.

Included Parts

• Mazworx Threaded O-ring Plugs
• Mazworx Threaded O-ring Freeze Plugs
• ARP Main Stud Kit

Note: Customers must send in a high-quality, virgin core block for machining. This upgrade is tailored for Nissan RB engine codes RB20, RB25, RB26, and RB30.