The Build Log at Original Z Works

Welcome to the Project Hannya build log — your front-row seat to a complete S30 transformation at Original Z Works.

This is a six-figure, no-shortcuts commission, expected to exceed $100,000 by completion, with fabrication beginning this fall. We're opening the doors from day one so you can watch a tired early Z become a modern-driving machine, one weld and one milestone at a time.

Our philosophy is simple: honest craftsmanship paired with tasteful, functional upgrades. We're starting with a solid 1972 Datsun 240Z chassis, while keeping an eye out for a clean 1970–1971 "Series 1" shell to use instead if we source one before fabrication begins. Whichever early chassis goes on the rotisserie, the goal never changes — preserve the classic silhouette and vintage soul of the car while thoroughly modernizing the structure and mechanicals underneath.

What follows is the full technical breakdown of how Hannya comes together. Bookmark this page and follow along as the work progresses.

🛠 Phase 1: Structural Fortification & Chassis Work

The unibody on these cars is famously thin and flexes under modern cornering loads, so we tackle the factory's weak points first — long before anyone thinks about paint or power.

Full-Length Reinforced Frame Rails: We cut away the compromised factory rails and weld in laser-cut, 11-gauge steel full-length replacements, tying the front and rear subframes into one rigid, stable backbone.

Stamped Floor Pan Replacement: The chassis is stripped to bare metal and fitted with new precision-stamped floor pans — fully plug-welded and seam-sealed — for a clean slate free of hidden fatigue or past corrosion.

Tubular Subframe Architecture: We replace the flimsy factory stamped-steel crossmembers with high-strength tubular front and rear subframes, modernizing the suspension pickup points and sharpening handling predictability.

Cadmium Hardware Refinishing: Every reusable factory nut, bolt, and bracket is acid-dipped and re-plated in authentic Yellow Zinc/Cadmium, for proper corrosion resistance and a clean, uniform finish underneath.

🏎 Phase 2: Powertrain & Engine Machining

Under the hood, the mission is to keep the period-correct look of a 1970s Nissan inline-six while building in high-quality internals and valvetrain geometry sourced from Japan.

The Engine Block: A 2.8L Nissan L28 F54 block — stress-relieved, deck-squared, and fully balanced for dependable performance at higher RPM.

The Cylinder Head: An early-production, high-compression High-Quench E88 head, whose tight combustion chambers promote the air/fuel turbulence needed for an efficient, clean burn.

The Kameari Valvetrain: To keep the valvetrain stable to a 7,500 RPM target, the head runs a Kameari 73A Street Spec camshaft (12.6mm lift), single beehive race springs, lightweight oversized stainless valves, and chromoly retainers.

Induction & Exhaust: Fuel and air come through a tuned set of triple side-draft carburetors on open velocity stacks, while an equal-length long-tube header scavenges spent gases into a classic twin-tip vertical muffler.

 Phase 3: Drivetrain, Suspension & Brakes

A high-revving engine requires a matching, lightweight drivetrain that can handle the power smoothly and distribute it predictably to the pavement without adding unnecessary unsprung mass.

5-Speed Gearbox Conversion: We are replacing the original 4-speed with a rebuilt close-ratio 5-speed manual transmission, paired with a Kameari Lightweight Chromoly Flywheel for sharper, more immediate throttle response.

Modernized Limited-Slip Differential: Rather than utilizing a heavy, bulky 1970s R200 unit, we are executing a lightweight Subaru WRX STI R180 Limited-Slip Differential conversion. Sourcing a highly sought-after 2004–2005 carrier gives us a robust, modern clutch-type mechanical LSD with a 3.90 gear ratio—perfectly matched to keep the Kameari 73A cam dead center in its powerband while shedding roughly 30 lbs of unsprung weight from the rear axle.

Bespoke Axle Integration: The modern Subaru carrier is adapted cleanly using 27-spline chromoly conversion stub shafts, allowing us to run upgraded, heavy-duty CV half-shafts while preserving the factory rear crossmember geometry.

Adjustable Suspension: Fully adjustable coilovers featuring Swift racing springs and Koni adjustable dampening are paired with bespoke tubular control arms, allowing us to dial in exact, predictable alignment and ride characteristics.

Disc Brake Upgrade: To bring stopping power up to modern standards, we are installing a 4-piston forged aluminum Wilwood brake kit up front, alongside a complete rear disc conversion and a larger 15/16-inch brake master cylinder.

🛋 Phase 4: The Interior & Cabin Environment

Inside, the approach is "OEM+": it should look factory-fresh to the eye while hiding subtle upgrades that make the car genuinely livable.

Reproduction Dashboard: A brand-new, uncracked OEM-reproduction dashboard assembly goes in — no plastic caps, no vinyl covers.

Sound & Heat Insulation: The cabin floor, doors, and rear hatch are lined with Dynamat Extreme to tame noise, vibration, and drivetrain heat before fresh black loop carpeting is laid down.

Integrated Climate Control: A Vintage Air HVAC system is concealed entirely behind the dash and operated through the factory mechanical sliders — modern air conditioning with a period-correct face.

🎥 Follow Along with the Progress

We build in the open. Expect weekly high-resolution photo galleries, fabrication updates, and engine assembly milestones posted right here as Hannya takes shape.

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