We made good progress on the audio system this week. Power cables for the amplifier are complete and the amp is now installed. The rear speaker enclosure has been assembled and mounted, with speaker wiring routed from the dashboard cubbies back to the rear box. Final securing of the wiring is next. This work brings us closer to a complete audio system for the 240Z.
We began installing the audio system this week, starting with modifications to the original faceplate to accept the new head unit. The original housing required custom work to fit the modern radio components while maintaining the period-correct appearance.
Once the faceplate work was complete, we assembled the radio components and began tracing the existing wiring. The car's audio wiring had been modified at some point in its history, so we're carefully mapping out what's there before making our connections.
We mounted the amplifier and began routing speaker wire through the cabin. We'd initially planned to install a powered mini subwoofer, but after test-fitting it we decided to swap it for a more compact JBL unit that better suits the car's interior space.
We completed the 3D scan of the rear undercarriage this week. The car arrived without its differential, so the scan captured the bare subframe and mounting points. This data will help us plan the exact placement of the cooling lines, high-voltage cables, and the differential mounting once that assembly arrives.
The scan presented some challenges due to surface conditions and required scanning with the car on the ground, but we captured the necessary reference geometry for the next phase of work.
We finalized the routing strategy for the main high-voltage cables and cooling lines this week. Both systems will run through the transmission tunnel from front to rear — two high-voltage cables and two cooling lines positioned at the bottom of the tunnel beneath the motor.
From there, the lines will route under and around the rear cubby area to clear the control arms and axles, then pass through the rear subframe into the battery compartment. We'll cut pass-through holes in the subframe when we notch it for the differential installation, ensuring everything is aligned and properly supported.
We finalized the brake system sizing this week. After calculating the fluid displacement requirements for the front and rear calipers, we confirmed that the 1.125-inch Wilwood master cylinder will provide the correct pedal ratio with the electric brake booster.
We also reviewed the brake line kit and hardware to prepare for installation.
We began modifying the original engine bay harness this week, removing unnecessary circuits and consolidating the remaining wiring. The old fusebox has been replaced with a new unit, and we're sourcing a proper cover for it.
As we stripped down the harness, we integrated the headlight relay upgrade directly into the main loom for a cleaner installation. We're adding a common 12V pass-through point on the firewall to serve as a junction between the original harness and accessory circuits. The engine bay harness will be taped up once we complete the front lighting connections.
We completed the installation of the Magnum evaporator unit this week. After removing old firewall insulation, we drilled and mounted the AC bulkhead fittings and installed the evaporator mounting points. The heater core lines are now routed into the engine bay — we installed them early since they're difficult to access once other components are in place.
With the evaporator mounted, we installed the defrost vents and began assessing the control system layout. The HVAC ducting is now in place and we're planning the final control integration.
We reviewed the existing OEM wiring harness and identified several upgrade components that will improve reliability. Three specific harness upgrades were sourced: a headlight relay upgrade to reduce load on the original switches, a replacement fuse box pigtail, and an upgraded parking light harness.
These components address known weak points in the original 240Z electrical system without requiring extensive custom work. The parts have been ordered and will be integrated into the existing harness in the coming weeks.
We completed the rear differential assembly for the 240Z this week. The pinion and carrier bearings were installed, and the pinion nut was torqued to achieve the correct preload. After installing the differential carrier, we set the ring gear backlash to spec, which required several test fits to dial in.
Once the backlash was set, we checked the gear contact pattern to verify proper meshing between the ring and pinion. The pattern looked good, so we torqued all fasteners to spec and marked each one as completed. The rear cover, main cap support bolts, and jam nuts were all installed with their respective torque values and thread locker where required.
The CV axle adapter flanges were bolted to the differential outputs with blue thread locker, completing the assembly. The rear end is now ready for installation in the chassis.
We disassembled both rear differentials this week to evaluate parts compatibility. After inspecting components from each unit, we confirmed the 2.73 gear set will work for the Z and ordered the remaining parts needed for the rebuild.
All bearings and seals have been removed from the differential housing. The bushings required more effort than anticipated — we ended up cutting them out with an air hammer rather than pressing them. That work is now complete and we're ready for the new parts to arrive.
The new climate control components arrived and we began installation. The condenser was assembled and installed first. We then assembled the evaporator unit and began fitting it into place. During test fitting, we identified a clearance concern with the heating element and blend door motor using the original mounting configuration. We're evaluating whether to modify the brackets or use an alternative heating approach. The evaporator unit remains partially installed while we finalize that decision.
We adjusted the passenger door to improve its fit and operation. The door was sitting too far outboard, which we traced to shims behind the upper hinge. After removing the shims and old masking tape, we made incremental adjustments until the door gap looked correct and the door closed properly. We may make final tweaks once the car is back on its wheels.
We finalized the audio system planning for the 240Z and prepared a tiered package presentation. The proposal builds on the layout we developed previously — front speakers in custom panels, 6x9 speakers in the rear hatch, a compact amplified subwoofer, and a four-channel amplifier.
The presentation includes options for the head unit configuration, either using the touchscreen GUI as the primary interface in the center console or installing a period-correct RetroSound unit with the GUI mounted discreetly. The package options are now ready for review.
We pulled the cover off the solid axle donor to drain the differential and verify the ring and pinion. The fluid came out clean and healthy, and we confirmed a 2.73 gear ratio with teeth in good condition.
The solid axle rear end is in usable shape and has been set aside for the machine shop. Next we'll inspect the independent rear suspension housing that will actually be used in the build.
We completed the brake system inspection and ordered the hydraulic components this week. The 240Z already has Wilwood four-piston calipers front and rear, along with stainless steel brake lines that need final installation.
We're adding a Gen 2 Bosch iBooster with a Wilwood master cylinder and the necessary adapter plate for the firewall. The fitting kit includes banjo adapters and brake hoses to connect the booster to the existing calipers. The parking brake strategy is still being determined.
We finalized the parts list for the 240Z's climate control system this week. The car will receive a Vintage Air Gen 5 evaporator kit and matching condenser with drier. These kits include the major hard parts needed for a complete air conditioning installation.
Additional components include reproduction heater control panels and decals to maintain the period-correct dashboard appearance. Parts are now on order.
We completed the parts research and ordering for the 240Z's rear differential this week. The car will receive a Ford 8.8 independent rear suspension unit with a 2.73 ring and pinion gear set. We're sourcing two 8.8 assemblies — one complete unit for the car, and a second donor to extract the 2.73 gears.
The parts list includes a limited-slip differential, polyurethane front bushings for the IRS cradle, and a complete rebuild kit with bearings and seals. All components are now on order, which will allow us to rebuild the rear end to spec once everything arrives.
The steering setup was inspected this week and looks good overall. The existing rack and linkage are properly configured and require no major modifications. We'll verify all fasteners are properly torqued and perform an alignment once the car is rolling.
During the inspection, we noticed the sway bars were missing and have ordered replacements.
We completed the A-plate harnesses for the battery boxes this week and documented all connections in the as-built folder. The harnesses are now installed along with the bus-bars for final testing.
We also installed the satellite module harnesses, bringing the battery box electrical system closer to completion.
We finished terminating all the host-side connectors for the battery boxes this week. The CAN communication lines received proper shielding, heat shrink, and identifying markers to keep everything organized for final installation.
