Datsun 240Z / 260Z / 280Z, Frequently Asked Questions

What is the difference between a 240Z, 260Z, and 280Z?

All three are variations of the original Datsun S30 platform, distinguished primarily by their engines:

• 240Z (1969-1973): L24 2.4-litre inline-six, twin SU carburettors, 151 hp. The original and most desirable. Slim chrome bumpers, lightest weight (1,060 kg).
• 260Z (1974-1976): L26 2.6-litre inline-six, twin SU carburettors, 162 hp. Heavier bumpers, available in 2+2 (longer wheelbase) configuration. The “emissions-era” Z-car.
• 280Z (1977-1978): L28 2.8-litre inline-six, Bosch L-Jetronic fuel injection, 170 hp. The most powerful and refined, but also the heaviest.

The chassis is fundamentally the same across all three, though the 260Z and 280Z received progressively heavier bumpers and more equipment. The 2+2 (260Z and 280Z) has a longer wheelbase and stretched roofline with small rear seats.

Which Z-car should I buy?

It depends entirely on your priorities.

For collecting and appreciation: The 240Z, specifically a Series 1 (round-tail, 1969-1971). It is the most valuable, the most historically significant, and the most desirable to collectors. But you will pay $70,000-150,000+ for a good one.

For driving and enjoying: The 280Z offers the best engine (the L28 is genuinely the strongest and smoothest L-series motor), the most refined chassis, and the lowest entry price. A good 280Z can still be had for $35,000-50,000.

For a modification/swap project: A 260Z coupe or 280Z. These are the least collectible in original form, so there is less guilt in modifying them. The 260Z 2+2 is the cheapest entry point if you are going to strip the interior and fit an RB anyway.

If budget is paramount: The 260Z 2+2 is the most affordable Z-car. Expect to pay $12,000-25,000 for a project, $25,000-40,000 for a driver.

How do I tell a Series 1 240Z from a Series 2?

The easiest identifier is the taillights: Series 1 (1969-1971) has round taillights, while Series 2 (1972-1973) has rectangular taillights. Other differences include:

• Series 1 has a flatter bonnet without the later bulge
• Series 1 interior is simpler with a different dashboard layout
• Series 1 uses round-top SU carburettors; Series 2 uses flat-top SUs
• Series 1 has different vent window latches and door handles

Chassis numbers (HLS30-xxxxxx) can confirm the production date. Series 1 cars generally have chassis numbers below approximately HLS30-100000 for the Australian market, though exact cutoffs vary.

Is the Z-car a good daily driver?

In honest terms: no, not really. A Z-car can be driven daily, and many people do, but you need to go in with realistic expectations.

Challenges of daily driving:

• No air conditioning on most models (some 280Zs had it as an option, it is marginal at best)
• No power steering (the steering is heavy at parking speeds)
• Noise and vibration at highway speeds are significant
• SU carburettors (240Z/260Z) need regular attention to run properly
• Boot space is limited
• Crash safety is non-existent by modern standards

What makes it workable:

• The L-series engine is reliable and easy to maintain
• Fuel economy is reasonable (10-13 L/100 km)
• Parts are available
• The car is genuinely fun to drive every time you get in it

If you want a Z-car as your only car, the 280Z with fuel injection is the most practical choice. If you have a modern daily driver and want the Z-car for weekends and club events, any variant works.

What is the deal with SU carburettors?

SU carburettors are constant-vacuum carburettors designed in Britain and used on Z-cars (and many British sports cars) through the 1970s. They work well when properly set up, but they require understanding and regular maintenance.

Common SU problems on Z-cars:

• Worn throttle shafts causing vacuum leaks, the single most common issue
• Hardened diaphragms and sticking pistons
• Worn needles and jets
• Leaking float valves
• Empty or incorrect damper oil

Maintenance required:

• Top up damper oil (SAE 20W) every 5,000 km
• Synchronise the carburettors using a Unisyn or similar tool every 10,000 km
• Full rebuild every 50,000-80,000 km or 10 years

A properly set up pair of SUs is a beautiful thing, smooth, responsive, and characterful. The problem is that finding someone who can tune them properly is becoming increasingly difficult. If your local Z-car club has an SU expert, buy them a beer regularly.

Should I convert to electronic fuel injection?

This is one of the most debated topics in Z-car ownership. The pragmatic answer is: it depends on what the car means to you.

Arguments for EFI conversion:

• Far more reliable than worn SU carburettors or aging L-Jetronic injection
• Better cold starting, better idle, better fuel economy
• Self-compensating for altitude, temperature, and humidity
• Allows proper tuning for modifications (camshaft, exhaust, etc.)
• A quality EFI system (Haltech, Link, MegaSquirt) with proper wiring is very reliable

Arguments against:

• Permanently alters the car from original specification
• Reduces collectability and value on a numbers-matching car
• Adds complexity (wiring, sensors, tuning) that the original car didn’t have
• A well-maintained set of SUs works perfectly well for a stock engine

The practical compromise: If you own a 240Z that is numbers-matching and in original condition, keep the SUs, the car is worth too much to modify. If you own a 260Z or 280Z that has already been modified, or if you are building a car for driving rather than showing, EFI is a sensible upgrade.

What about the RB engine swap?

The RB swap is the elephant in every Z-car conversation. Here is the honest assessment.

Why people do it: The RB20DET, RB25DET, and RB26DETT are brilliant engines that fit the Z-car’s engine bay with relatively minor modifications. The combination of a lightweight Z-car body with a turbocharged RB engine produces a genuinely quick, exciting car. Aftermarket support for RB engines in Australia is outstanding.

What it costs: A quality RB25DET swap, engine, gearbox, wiring, ECU, cooling, exhaust, and tuning, runs $8,000-15,000 all-in for a competent DIY build using secondhand components. A professionally built RB26DETT swap can exceed $30,000.

What it does to the car’s value: An RB swap permanently reduces the value of a Z-car as a collectible. A numbers-matching 240Z is worth $80,000-150,000+. An RB-swapped 240Z is worth $40,000-60,000 regardless of how well the swap is done. The maths is clear.

The sensible approach: If you want an RB Z-car, start with a 260Z 2+2 or a rough 280Z, the least collectible variants. Do not RB-swap a clean 240Z. It is financial vandalism.

How much rust is too much rust?

There is no simple answer, but here are some guidelines:

Acceptable: Surface rust on non-structural panels. Light rust in the spare wheel well. Minor bubbling on the rear quarter panels. These are normal for a 50-year-old car and can be addressed during a respray.

Concerning but fixable: Perforated floors (repair panels are available), battery tray corrosion (replacement trays exist), and door bottom rust (replacement doors from a wrecker).

Walk away: Strut towers that are cracked or perforated (safety issue, suspension attaches here), sills that crumble when prodded (structural), and extensive firewall corrosion. These repairs are possible but the cost will exceed the car’s value in most cases.

The rule of thumb: If you can see rust, there is three times as much hidden behind it. A car that looks “mostly okay” from the outside can be a horror underneath. Always inspect from below, and always bring a screwdriver.

What fuel should I use?

All L-series engines should run 95 RON premium unleaded at minimum. 98 RON is recommended for peace of mind, particularly on high-compression engines or in hot weather.

Do not use E10 on a Z-car with original rubber fuel lines, the ethanol attacks aged rubber and can cause fuel leaks. If you want to run E10, replace all fuel hoses with ethanol-compatible rubber or braided stainless.

The original L24 and L26 engines were designed for leaded fuel. The valve seats and guides benefit from a lead replacement additive if the car is driven hard. For normal driving, modern unleaded fuel with 95+ RON is fine.

How do I find a good Z-car mechanic in Australia?

Your best resource is the local Z-Car Club or Datsun Sports Owners Club. Every state has at least one, and the members will know which mechanics understand these cars. Generic mechanics can handle basic servicing, but for carburettor tuning, fuel injection diagnosis, and chassis/rust assessment, you need someone who has worked on Z-cars specifically.

Some well-known Z-car specialists in Australia include workshops in Melbourne, Sydney, and Brisbane that specialise in Datsun/Nissan classics. The club forums will have current recommendations. Join the club before you buy the car, the membership fee will save you thousands in avoided mistakes.

Are parts still available?

Yes, but the situation varies by component.

Readily available: Engine internals (pistons, bearings, gaskets, timing chains), suspension components (shocks, springs, bushings), brake parts (pads, rotors, cylinders), and most electrical components (alternators, starters, ignition parts). These are available from Australian and US specialists.

Available but expensive: Body panels (reproduction floor pans, sills, quarter panels from Tabco and Motor Sport Auto in the US), rubber seals (door seals, windscreen seals, hatch seals), and interior trim (seats, dashboards, carpets). Quality of reproduction parts varies significantly.

Difficult to source: Original SU carburettors in good condition, L-Jetronic airflow meters, original instrumentation, NOS chrome trim, and model-specific unique parts (early Series 1 components). For these items, the global Z-car community and specialist dealers are your best bet.

What is the car worth with a rebuilt engine versus an original engine?

A numbers-matching car, where the engine number matches the chassis number on the compliance plate, is worth significantly more than a car with a replacement or rebuilt engine. For a 240Z, the premium can be 20-40%.

However, “numbers matching” does not mean “never touched.” An engine that has been rebuilt with standard-specification parts retains its matching status as long as the original block and head are used. Boring the cylinders, fitting new pistons, and replacing bearings does not break the matching, swapping the entire engine does.

If you are buying for investment, numbers matching matters enormously. If you are buying to drive, a properly rebuilt engine is arguably better than a tired original, it will run better, last longer, and cost less to maintain.

Can I register a Z-car on club plates in Australia?

Yes. In most Australian states, Z-cars qualify for club registration (conditional registration) schemes that offer reduced registration costs in exchange for restricted use. The specific rules vary by state:

• Victoria: Club Permit Scheme (CPS). Car must be 25+ years old. Limited to club events, maintenance runs, and a set number of days per year.
• New South Wales: Historic Vehicle Scheme. Car must be 30+ years old. Similar restrictions to Victoria.
• Queensland: Special Interest Vehicle. Various categories with different rules.
• South Australia, Western Australia, Tasmania: Each state has its own historic/conditional registration scheme.

Club registration typically requires membership of a recognised car club (Z-Car Club, Datsun Sports Owners Club, or a general classic car club). The cost savings are significant, often $200-400 per year instead of $700-1,000+ for full registration.

What should I budget for annual running costs?

For a Z-car in good running condition, driven 5,000-10,000 km per year:

• Insurance (agreed value): $800-2,000/year depending on the car’s value
• Registration: $200-400 (club plates) or $700-1,000+ (full registration)
• Servicing (2-3 services per year): $400-800 DIY, $800-1,500 at a specialist
• Fuel: $1,000-2,000 (at ~12 L/100 km and current fuel prices)
• Consumables (tyres, brake pads, filters): $500-1,000
• Unexpected repairs (budget): $1,000-2,000

Total: approximately $4,000-7,000 per year for a car in good condition. A car that needs ongoing rust repair, engine work, or mechanical restoration will cost significantly more. Budget accordingly and do not underestimate the cost of parts for a car in this value range.