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Neubs' 1971 240Z stroker build

Neubs · 1971 Datsun 240Z

Datsun 240Z (S30)2-page write-up

Neubs 1971 240z

Read the full write-up at Neubs 1971 240z ↗

Photo: Neubs 1971 240z

A 1971 Datsun 240Z with a stroked L28 and evolving SU/EFI tuning

Neubs documents long-term work on his 1971 240Z, originally a daily driver with its factory L24, now built around a stroked and balanced L28-based engine running round-top Hitachi SU carbs. The thread covers carb needle tuning, a Megasquirt ignition conversion, a distributor swap, a full brake rebuild, and the start of a move to EFI with Whitley Tune, with dyno runs tracking progress toward a 200whp target.

Specs

As stated in the original write-up.

Engine
Stroked L28 F54 block to 2996cc with 10-10.5:1 compression
Cylinder head
L28 N42 head with 1.0mm O/S Ferrea Super Flo valves
Crankshaft
LD28 V07 crank, knife-edged, nitrided and balanced
Carburettors
Round-top Hitachi SU carbs with SB needles
Exhaust
Full stainless Zstory system with Zstory race sport header
Ignition
Megasquirt MS1 ignition-only control triggered off an L20ET optical distributor
Brakes
Rear drum cylinders and master cylinder resleeved, NOS master cylinder fitted, front calipers rebuilt
Power output
201.6 rwhp on dyno with fuel and ignition tune

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 4

Fuel & Ignition 7

Brakes 2

Photos

16 pictures collected from the write-up, in the order they were posted, shown from Neubs 1971 240z. A picture opens larger here, with the way through to the page it is on.

Neubs · 2018-09-04T12:30:45Z 4this post at Neubs 1971 240z ↗

Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z

Neubs · 2018-09-06T03:12:18Z 3this post at Neubs 1971 240z ↗

Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z

Neubs · 2019-02-09T22:04:11Z 2this post at Neubs 1971 240z ↗

Photo: Neubs 1971 240z
Photo: Neubs 1971 240z

Neubs · 2020-04-12T20:04:01Z 3this post at Neubs 1971 240z ↗

Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z

Neubs · 2020-06-19T20:03:27Z 4this post at Neubs 1971 240z ↗

Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z
Photo: Neubs 1971 240z

How it was done

Starting condition

The car is a 1971 240Z bought in 2009, originally a daily driver with the factory L24 engine, a 280ZX gearbox and ignition, and a respray to red decades earlier. Mileage added was minimal for years before the owner began focused work on it.

Stroker engine and carb tuning

The build centres on a stroked, balanced L28-based engine with a 2996cc displacement, fitted long before serious work began. Recent efforts focused on optimising round-top Hitachi SU carburettors, testing needle profiles and adjusting float levels to chase a 200whp target with a new Zstory stainless exhaust.

Megasquirt ignition conversion

An MS1 Megasquirt board was revived and configured for ignition-only control, including building a launch control trigger circuit, locking mechanical advance, wiring the harness, and troubleshooting a faulty harness before getting the engine running and logging data with an added wideband.

Distributor swap

After intermittent ignition issues, the owner moved from the original Pertronix-triggered distributor toward a gifted optical distributor, ultimately rebuilding and fitting an L20ET turbo distributor housing with a new crank angle sensor so Megasquirt could read it reliably.

Brake rebuild

What began as fixing a sheared bleed nipple became a full rear brake rebuild: drum cylinders and the master cylinder were resleeved by a specialist, a NOS master cylinder was sourced, and the front calipers were rebuilt in-house, with drums retained at the rear.

Move toward EFI

Most recently the owner began converting the ignition-only Megasquirt setup to run fuel injection, working with Whitley Tune on a prototype sport injection kit with 50mm throttle bodies, and fitting dual lambda sensors at the exhaust collectors to tune separate injector banks.

A summary in our own words. The full account, with all its detail, is in the original write-up: read it at Neubs 1971 240z ↗

Worth knowing

  • Balancing a motor's rotating assembly took considerable extra effort that may be excessive for an engine not revved past 6.5k
  • Bending the float tabs in small increments required a lot of patience to stop the rear float bowl sticking

Neubs 1971 240z

forum thread: 2 of 2 pages and 35 posts inspected; 30 unquoted updates by Neubs used; 5 replies excluded; long updates shortened to fit the text allowance; coverage is partial on 7 November 2026. The original write-up and photographs remain with their creators. This page is a catalogue in our own words, and a signpost to the source.

Read the full write-up at Neubs 1971 240z ↗

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