Better Than Butter: 1970 Datsun 240Z (S1) restoration
Better Than Butter S1
Photo: Better Than Butter S1A 1970 Datsun 240Z (S1) revived with its original documentation
The builder bought a one-owner, well-documented 1970 Datsun 240Z found through a Facebook post and set about refurbishing its suspension, brakes, fuel system, wiring, interior and drivetrain. Along the way the stock R200 diff was swapped for a Subaru R180, and the engine was rebuilt and detailed with period-correct parts and upgraded ignition.
Specs
As stated in the original write-up.
- Engine
- L24 2.4L bored 1mm over, Nissan comp 9mm rods, flat top pistons, blueprinted and balanced, Rebello Racing E-31 head
- Camshaft
- Custom ground cam by ISKY
- Valvetrain
- Nissan comp valves and springs
- Exhaust
- MSA 6-1 headers, 2.5 inch exhaust with turbo muffler
- Transmission
- ZX 5-speed
- Carburetors
- Custom bored carbs with custom jets and needles
- Rear axle
- 3.9 R180 from a Subaru WRX STI, with John Williams companion flanges
- Suspension
- NOS Tokico Illumina 5-way shocks and springs, Energy Suspension poly bushings, Bad Dog sway bar braces
- Wheels
- Authentic SSR SpeedStar Watanabe RS-Eight wheels, refinished and powder coated, 5mm rear spacer
- Fuel tank
- S30World.com european-spec reproduction fuel tank
- Roll cage
- Bolt-in roll cage from AGI, Australia
- Wiring harness
- Fully re-connectored harness using a kit from Vintage Connections
- Paint
- Mercedes off-white, applied in the late 1980s by the original owner; not yet repainted
Parts used
Parts named as used in the original write-up, grouped the way the Parts page groups them. Where one of the shops we index lists the same thing for this car, it is shown underneath with a link to the shop.
Engine 2
- Rebello Racing E-31 cylinder headRebello Racing
Fitted to the L24 engine build
In the shops
VP Racing Cool Down Coolant Additive (16oz) ↗
MazSpec MX-5 Spares & Accessories· £14.40 GBP
VP Racing Power Boost Fuel Additive (473ml) ↗MazSpec MX-5 Spares & Accessories· £15.00 GBP
VP Racing Stay Frosty Race Ready Coolant - 3.78L ↗MazSpec MX-5 Spares & Accessories· £27.95 GBP - ISKY custom ground camshaftISKY
Fitted as part of engine rebuild
In the shops
Isky High Performance Racing Camshaft ↗
Z Car Depot· $659.00 USD
Isky Stage 3 Racing Camshaft for Nissan L28 Engine ↗
JDM Car Parts· $663.99 USD
Isky Performance Camshaft (Datsun L16/L18/L20B) ↗Z Car Depot· $449.00 USD
Fuel & Ignition 3
- Mallory Unilite distributor moduleMallory
Installed after the Petronix ignitor signal proved too weak for the MSD box
In the shops
Distributor Rotor (Mallory 308) ↗
Belcher's American Auto Parts (UK)· $28.00 USDDistributor Rotor, Mallory Unilite Distributor ↗Motorsport Auto (The Z Store)· $28.14
Mallory Unilite Distributor, 70-74 240Z-260Z, *75-83 ↗ - Reproduction fuel tankS30World.com
European-spec copy fitted to eliminate rust-prone original tank
- Aluminum fuel lines
Replaced all supply and return lines
Gearbox & Drivetrain 3
- Subaru R180 differential (3.9)Subaru
Swapped in from a Subaru WRX STI to replace the welded R200
In the shops
Stub Axle Set for Subaru R180 Differential Conversion ↗JDM Car Parts· $498.00 USD
Subaru R180 LSD Stub Axles Set ↗
DTSN.eu· 399.00
OEM Differential Axle O-Ring R180 ↗Z-Services· €2.30 EUR
- Companion flangesJohn Williams
Sourced for the R180 differential swap
In the shopsCompanion Flange (70-73 240Z) ↗
OEM Companion Flange (R180 Differential) ↗Companion Flange, Refurbished, 70-73 240Z ↗ - ZX 5-speed transmission
Installed as the gearbox
In the shops
Front Transmission Oil Seal (5-Speed) ↗
Flyin' Miata· $7.29 USD
Automatic Transmission Speed Sensor, X300 ↗
Moss Motors – Triumph TR6/TR250· $87.83 USD
Front Transmission Oil Seal (6-Speed, 1999-2005) ↗Flyin' Miata· $20.99 USD
Suspension & Steering 3
- Energy Suspension poly bushingsEnergy Suspension
Fitted throughout during suspension refurbishment
In the shops
Energy Suspension Hyper-Flex Master Bushing Set, Red - 02-05 Civic ↗
JDMuscle — Mazda MX-5· $244.31 USD
Energy Suspension Front Control Arm Bushing Set, Red - 99-00 Civic ↗JDMuscle — Mazda MX-5· $104.16 USD
Energy Suspension Front Control Arm Bushing Set - Red (96-00 Civic) ↗JDMuscle — Mazda MX-5· $90.63 USD - Tokico Illumina 5-way shocks and springsTokico
NOS period-correct shocks and springs fitted
- Rebuilt steering rackRock Auto
A spare rack was rebuilt using parts sourced from Rock Auto and bearing suppliers
In the shops
Steering Rack Stop ↗
TRGB· £4.95 GBPSteering Rack Spacer ↗
bpnorthwest.com· $17.10 USD
Steering Rack Boot Kit ↗bpnorthwest.com· $11.02 USD
Brakes 4
- Stop Tech drilled and slotted rotorsStop Tech
Fitted on all corners with new bearings and extended studs
In the shops
Drilled and Slotted Brake Rotor Set ↗bpnorthwest.com· $125.99 USD
Rear Brake Rotor Set, Drilled and Slotted ↗
Good Parts· $220.00 USD
Brake Rotor Set, Drilled and Slotted (Spitfire) ↗bpnorthwest.com· $119.85 USD - Porterfield rear drum padsPorterfield
Fitted to rear drum brakes
In the shops
Porterfield R4S Brake Pads, Rear (NC/ND) ↗Flyin' Miata· $119.00 USD
Porterfield R4S Brake Pads, Rear (1990-93 size) ↗Flyin' Miata· $105.00 USD
Porterfield R4S Brake Pads, Front (NC) ↗Flyin' Miata· $139.00 USD - EBC Greenstuff front padsEBC
Fitted to front calipers
In the shops
EBC Greenstuff Front Brake Pads (X-Type) ↗Moss Motors – Triumph TR6/TR250· $105.20 USD
Front Brake Pads EBC Greenstuff (Elan +2) ↗
Tony Thompson Racing· £45.00 GBP
EBC Greenstuff Front Brake Pad Set (Mk1 1.6) ↗
MX5 City· $69.86 USD - T3 handbrake cableT3
Used to refurbish the e-brake system
Wheels & Tyres 1
- SSR SpeedStar Watanabe RS-Eight wheelsSSR
Authentic set refurbished, refinished barrels and powder coated faces, new hardware, 5mm rear spacer
Body & Trim 2
- Bad Dog sway bar bracesBad Dog
Welded into the engine bay
In the shops
Front Sway Bar ↗Flyin' Miata· $219.00 USD
Front Sway Bar ↗Flyin' Miata· $259.00 USD
Sway Bar End Link ↗Moss Motors – Triumph TR6/TR250· $16.99 USD - AGI bolt-in roll cageAGI
Custom-measured bolt-in cage fitted with minimal modification
In the shops
Roll Cage Padding 1m x 3" ↗
C Bradley Motorsport· £14.00 GBPDifferential Cage Roll Pin ↗bpnorthwest.com· $1.74 USD
OMP Roll Cage Padding 490mm ↗C Bradley Motorsport· £27.80 GBP
Interior 1
- Dash pad / capVintage Dash
Original cracked pad removed, gauges restored, plastic cap fitted while awaiting a replacement pad
In the shops
Isky Valve Cap Lash Pad for Racing Cams ↗Z Car Depot· $18.50 USD
Electrical 3
- Wiring connector kitVintage Connections
Used to replace every connector on the harness
- Hella hornsHella
Installed in place of stock horns
In the shops
Hella 12V Twin Trumpet Horn Kit with Bracket - Toyota ↗JDMuscle — Mazda MX-5· $43.00 USD
Hella Horn Kit with Mounting Bracket and Wiring Harness (02-21 WRX/STI) ↗JDMuscle — Mazda MX-5· $129.00 USD
Radiator, Hella ↗Moss Europe (UK)· £291.25 GBP - MSD digital 6AL ignition boxMSD
Used to power the ignition
Photos
147 pictures collected from the write-up, in the order they were posted, shown from Better Than Butter S1. A picture opens larger here, with the way through to the page it is on.
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How it was done
Finding a documented survivor
The builder found the car through a Facebook listing posted on behalf of its original, now 87-year-old owner. It was a one-owner 1970 240Z ordered in late 1969, delivered in April 1970, with extensive maintenance paperwork. The car had moved from California to the east coast and sat in a warehouse since 2003. A factory NOS L28 long block had been fitted in 1990 after the original engine failed, which had put off other buyers. The seller's documentation convinced the builder to buy it.
Suspension and brakes
The suspension was media blasted, coated with SEM chassis paint, and rebuilt with new poly bushings and NOS period Tokico shocks and springs, chosen to keep things period correct. The rear subframe was modified for a solid differential mount and reinforced against cracking. All brake components were renewed, including rotors, pads, calipers, bearings, studs and the handbrake system, finished with fresh paint on shields and backing plates.
Fuel, wiring and interior
A reproduction European-spec fuel tank and new aluminum fuel lines replaced the old fuel system. The wiring harness had every connector replaced after testing, using a kit from Vintage Connections, keeping factory-style connectors even for aftermarket electronics. The cracked dash pad was removed and the gauges restored, with a plastic dash cap fitted while awaiting a replacement pad.
Drivetrain and driveline changes
The engine is a built L24, bored, balanced and fitted with a Rebello Racing E-31 head, ISKY cam, and upgraded ignition. After running the welded stock R200 differential, the builder swapped to a 3.9 R180 unit sourced from a Subaru WRX STI for better low speed manners. A bolt-in roll cage from AGI was fitted, and an authentic set of Watanabe wheels was refurbished and installed.
Progress so far
After about four months apart, the car was made to roll, drive and stop again with all mechanical systems renewed, though the paint remains the original late 1980s finish rather than a fresh repaint. The builder mentioned a possible repaint to the correct 901 silver in the future, but this had not happened at the time of posting.
A summary in our own words. The full account, with all its detail, is in the original write-up: read it at Better Than Butter S1 ↗
Worth knowing
- Modifying systems while retaining the ability to revert to stock preserves future options on a valuable car
- Stock-style connectors throughout make aftermarket electronics easier to service later
- A properly set up stock-based brake package with good pads can outperform an unnecessary big brake upgrade