Mazda RX-7 FB, Frequently Asked Questions

What is the FB RX-7?

The FB (also known as the SA22C in Series 1-2) is the first-generation Mazda RX-7, produced from 1978 to 1985. It’s a front-mid engine, rear-wheel drive sports car powered by the 12A (Series 1-2) or 13B (Series 3) twin-rotor Wankel rotary engine. The FB weighed approximately 1,050 kg and featured pop-up headlights, a hatchback body, and near-perfect weight distribution. It was designed as Mazda’s answer to the Porsche 924, at roughly half the price.

Should I buy a Series 1, 2, or 3?

Series 3 with the 13B engine is the recommended choice for most buyers. The 13B offers meaningfully more torque than the 12A (170 Nm vs 137 Nm), is more robust, and has better parts availability. The Series 3 also received improved brakes and suspension. The Series 1 and 2 with the 12A are lighter and more affordable, but the 12A’s relative lack of low-end torque and shorter apex seal life make the 13B a better proposition for everyday enjoyment.

How do I know if the engine is healthy?

Compression test. This is non-negotiable. Warm the engine to operating temperature, remove all four spark plugs, and test each rotor with a standard compression gauge. The 13B should show 110-130 psi per face with less than 10 psi variation across all six readings. The 12A should show 100-120 psi. Below 85 psi on any face, or more than 15 psi variation, means the engine needs a rebuild. Also listen for unusual noises, a chattering or metallic ticking from the engine at idle can indicate apex seal issues, though this is not always present.

What is pre-mixing and should I do it?

Pre-mixing means adding two-stroke oil to your fuel to provide additional lubrication for the apex seals. The factory oil metering pump (OMP) is designed to handle this, but the OMP is a 40+ year old mechanical component that can fail without warning. Pre-mixing (typically 25-35ml of two-stroke oil per 10 litres of fuel, or roughly a 1:200 ratio) provides insurance. If the OMP fails, the pre-mix keeps the seals lubricated. Most experienced rotary owners pre-mix as standard practice. Use a quality two-stroke oil, Penrite MC-2 or Idemitsu premix are popular choices.

How much fuel does the FB use?

Expect 13-16 L/100km in mixed driving. The 12A is slightly better than the 13B due to smaller displacement, but neither is fuel-efficient by any standard. Highway cruising at moderate speed will give you the best economy; spirited driving on back roads will push consumption toward 18-20 L/100km. Use 98 RON premium unleaded. Accept the fuel bill as part of the rotary experience, the engine’s character is worth the extra cost.

Can I daily drive an FB RX-7?

Yes, with caveats. The FB is comfortable enough for daily use, the seats are supportive, visibility is good, and the hatchback offers practical cargo space. The driving experience is engaging without being exhausting. However, the car is 40+ years old: there are no airbags, no ABS (on most models), and the crash structure is 1970s engineering. Roadside breakdowns are possible, carry basic tools and a litre of coolant. The fuel consumption is significant if you’re commuting long distances. Many FB owners daily drove these cars for years and loved every minute, but you need to be comfortable with vintage car ownership.

What’s the worst thing that can happen to the engine?

Overheating. A single severe overheating event can warp the rotor housings, score the housing surfaces, destroy the apex seals, and turn a healthy engine into a core for rebuild. The rotary engine has very tight tolerances and thin housing walls, it cannot absorb the thermal distortion that a cast-iron piston engine can. The cooling system is the single most critical system on the car. If you buy an FB, replace the entire cooling system (radiator, hoses, thermostat, water pump) as your first priority, regardless of its apparent condition.

How much does it cost to rebuild the engine?

A quality 13B rebuild at a rotary specialist costs $2,500-4,000 AUD. This includes all seals (apex, side, corner, oil, water), new bearings, gaskets, and labour. Rotor housing resurfacing adds $200-400 per housing if needed. If the housings are beyond resurfacing (deep scoring, warping), replacement housings add $400-800 each. A 12A rebuild is slightly less expensive but parts are scarcer. Always use a rotary specialist, the assembly process requires specific knowledge, tools, and torque sequences that a general mechanic will not have.

What modifications should I do first?

Before modifying anything, make the car reliable. The priority list: (1) Complete cooling system replacement, aluminium radiator, silicone hoses, new thermostat and water pump. (2) Ignition upgrade, replace the factory ignition with a modern electronic system. (3) Exhaust, a stainless steel system improves flow and longevity. Once the car is sorted, suspension upgrades (shocks, springs, bushings) make the biggest difference to the driving experience. Resist the temptation to port the engine until you’ve experienced the stock setup, a well-sorted stock 13B in an FB is a genuinely enjoyable drive.

Is the 12A or 13B better?

The 13B is better in almost every respect for street use. It has more displacement (1,308cc vs 1,146cc), more torque (170 Nm vs 137 Nm), longer apex seal life, stronger bottom end, and better parts availability. The 12A is adequate in the lightweight FB, but the 13B transforms the car from “quick” to “properly fast.” The only argument for the 12A is originality on a Series 1 or 2 car being kept in factory specification.

Can I swap a 13B into a Series 1 or 2?

Yes, and it’s a very common upgrade. The 13B is a direct fit in the FB engine bay with minor modification. You’ll need the 13B engine, appropriate mounts, a compatible bellhousing and gearbox (or adapter), and the exhaust system modified to suit. Many Series 1 and 2 cars have been converted, and the rotary community has thoroughly documented the process. Cost: $2,000-5,000 depending on the engine source and supporting modifications.

How do I find a good rotary mechanic?

Ask the rotary community. In Australia, the major rotary clubs and online forums (RotaryCarClub.com.au, the Mazda Rotary Club of Victoria, and various Facebook groups) maintain lists of trusted specialists. Key rotary engine builders and specialists in Australia include Pac Performance (Sydney), Promaz Performance (Melbourne), and various independent shops. A good rotary mechanic will own or have owned rotary cars, they need to understand the engine from an owner’s perspective, not just a textbook perspective.

What causes hard starting?

Several possibilities: low compression (the primary cause, do a compression test), weak ignition (worn spark plugs, degraded leads, failing coil), flooded engine (excess fuel in the combustion chamber, hold the throttle wide open and crank for 10-15 seconds to clear it), or a weak starter motor (the rotary needs a strong cranking speed to build compression). Hot starting problems specifically suggest low compression, as the engine heats up, metal expansion reduces the already-marginal seal contact, and a weak engine that starts fine cold may refuse to restart when hot.

What’s the difference between the FB and FC RX-7?

The FC (1985-1992) is the second-generation RX-7. It’s a larger, heavier (1,200-1,300kg vs 1,050kg), more refined car with a turbocharged option (the FC Turbo II producing 200hp), independent rear suspension, and a more sophisticated interior. The FC is a grand tourer where the FB is a lightweight sports car. The FC is faster in a straight line (especially the turbo), but the FB is lighter and more nimble. Many enthusiasts prefer the FB’s purity and simplicity to the FC’s refinement.

Are parts still available?

Mechanical parts, engine seals, gaskets, bearings, brake components, suspension bushings, are well-supplied through rotary specialists and general parts retailers. The FB shares many components with the FC RX-7, which broadens availability. Body panels and trim are the challenge, used panels from wreckers are becoming scarce, and aftermarket reproduction panels are limited to common rust areas. Interior parts (dashboard components, switches, trim pieces) are difficult to source. The global FB community is well-connected for parts sourcing, and international shipping from the US and Japan is common.

How often should I change the spark plugs?

Every 15,000-20,000 km. The rotary engine is harder on spark plugs than a piston engine due to the combustion chamber’s characteristics, the plug fires into a moving chamber that passes the plug twice per rotor revolution. Use the correct plug type (NGK BUR7EQ or equivalent, check your specific application) and the correct gap. The FB uses a leading and trailing plug per rotor, both must be in good condition for smooth operation. Some owners carry a spare set of plugs in the car as a diagnostic tool.

Is the FB a good first sports car?

The FB is an excellent first sports car for someone willing to learn. It’s mechanically simple, well-documented by the enthusiast community, and the rear-wheel-drive chassis is predictable and forgiving. The relatively modest power output (100-135hp) means you can explore the car’s limits without getting into serious trouble. The rotary engine requires learning a different maintenance philosophy (pre-mixing, compression testing, cooling system vigilance), but this is part of the appeal. Buy a Series 3 with a healthy 13B, sort the cooling system, and enjoy one of the most rewarding affordable sports cars ever made.

Should I get the manual or automatic?

Manual. The 5-speed manual is a satisfying gearbox with a positive shift action, and it’s integral to the FB’s character as a driver’s car. The 3-speed automatic is adequate for transport but removes the engagement that makes the FB special. Manual FBs are worth 15-20% more than automatics and are far more sought-after. If you find the right car and it happens to be an auto, a manual conversion is possible using parts from a manual donor car.

What wheel and tyre sizes fit the FB?

The factory fitment is 13” wheels with 185/70R13 tyres (early) or 14” wheels with 195/60R14 tyres (later/sport). Common upgrades include 15” x 7” wheels with 205/50R15 tyres, which offer improved grip without compromising the ride. The bolt pattern is 4x114.3 with a 54.1mm centre bore. Avoid going too wide or too large, the FB is a light car designed around narrow tyres, and excessively wide rubber adds unsprung weight and can overwhelm the suspension geometry.