Nobody owns a rotary by accident. You buy an RX-7 or an RX-8 because you want something different, and you keep it because nothing else drives or sounds the same. The catch is that rotary engines do not forgive neglect, and sooner or later most owners find themselves looking for a Mazda 13B rotary engine for sale.
We sell tested, fairly used 13B engines and ship them worldwide to owners, rotary shops and importers. Every engine is compression tested with a proper rotary tester, and you get the readings for every rotor face, photos of the real engine, a written quote and a warranty before you pay.
Want a price? Send your car and chassis code through our contact page or call +1 (209) 733-0882. You can browse our used engines or go straight to the Mazda 13B Rotary Engine for Sale product page to see the price.
This guide covers how the 13B works, its specs, every main version, the faults that kill these engines, how rotary compression testing really works, seven checks before you buy a Mazda 13B rotary engine for sale and how to keep it alive once it is in.
What Is the Mazda 13B?
The 13B is a twin-rotor Wankel engine. Instead of pistons going up and down, it has two triangular rotors spinning inside oval-shaped housings. Each rotor turns an eccentric shaft, which does the job a crankshaft does in a normal engine. There are no valves, no camshafts and no timing belt. Fuel and air come in through ports in the housings, and the rotor itself opens and closes them as it turns.
Mazda first used the 13B in the 1970s and kept developing it for nearly forty years, all the way to the RX-8, which ended production in 2012. You can read the full story in Mazda Wankel engines. Along the way it got fuel injection, turbos, twin sequential turbos and finally side exhaust ports in the Renesis.
The design is light, compact and smooth, and it revs freely. But it depends on thin seals at the tips and sides of each rotor, and those seals are what most problems come back to. That is why buying a Mazda 13B rotary engine for sale is not like buying a used piston engine.
Mazda 13B Rotary Engine Specifications
Here are the main figures. Power varies a lot between versions, so we always tell you exactly which Mazda 13B rotary engine for sale you are getting.
| Type | Twin-rotor Wankel rotary, petrol |
| Displacement | 1,308 cc (654 cc x 2 rotors) |
| Rotor width | 80 mm |
| Spark plugs | Two per rotor, leading and trailing |
| 13B-DEI (FC RX-7) | About 146 to 160 hp |
| 13B-T (FC Turbo II) | About 182 to 215 hp |
| 13B-REW (FD RX-7) | About 252 to 280 PS, twin sequential turbos |
| 13B-MSP Renesis (RX-8) | About 189 to 238 hp |
| Redline | About 7,000 to 9,000 rpm depending on version |
| Lubrication | Wet sump plus an oil metering pump that feeds oil into the housings |
| Cooling | Liquid |
| Timing drive | None, no valves or camshafts |
One thing surprises new owners: a rotary is supposed to use oil. The metering pump injects oil into the housings to lubricate the seals, and that oil gets burned. Checking the level often is part of owning one.
Every Main 13B Version
Early 13B and 13B-RESI
Carburettor engines from the 1970s, then the injected RESI engine in the mid 1980s. Mostly of interest to restorers of older Luce, Cosmo and early RX-7 models.
13B-DEI
The naturally aspirated FC RX-7 engine, about 1986 to 1991. Simple, cheap to run and a good base for a budget car.
13B-T
The FC Turbo II engine with a single twin-scroll turbo. Popular for budget builds because it takes boost well with a good tune.
13B-RE
A twin turbo engine found in the JC Cosmo in Japan. Rare outside that car.
13B-REW
The FD RX-7 engine from about 1992 to 2002, with twin sequential turbos. This is the Mazda 13B rotary engine for sale most people ask us for, and it is what our product page price is based on.
13B-MSP Renesis
The RX-8 engine, with side exhaust ports instead of peripheral ones. It came as a 4-port standard power engine and a 6-port high power engine. Usually cheaper than an REW, and quoted separately.
These are not simple swaps between cars. Wiring, computers, intakes, mounts and even the oil system differ. Before you pick a Mazda 13B rotary engine for sale, tell us the car and chassis code.
Which Cars Use the 13B?
- Mazda RX-7 FC, about 1986 to 1991
- Mazda RX-7 FD, about 1992 to 2002
- Mazda RX-8, about 2003 to 2012
- Mazda Cosmo and Luce in some markets
- Earlier RX-7 SA and FB models with later 13B swaps
A Mazda 13B rotary engine for sale also suits swaps into lightweight cars like the MX-5 and older Mazdas are also popular, and we cover those further down.
Why 13B Engines Fail
When a rotary dies, it is almost always one of these:
- Overheating. This is the big one. Heat warps housings and cooks the coolant seals between them.
- Worn apex seals. The seals at the tips of the rotors wear over time, and compression drops. The car gets hard to start hot and loses power.
- Running low on oil. Owners who never check the level between changes run the engine short.
- Flooding. Especially on the RX-8, starting the engine cold and switching it off straight away can flood it.
- Detonation on turbo engines. A bad tune or poor fuel can break apex seals in one go.
So before you fit a Mazda 13B rotary engine for sale, find out what killed the old engine. If it was heat, the cooling system needs serious attention first.
How Rotary Compression Testing Really Works
This is the single most important thing to understand before you buy. A normal piston engine compression gauge gives you one number per cylinder. On a rotary that number is almost useless, because each rotor has three faces, and each face makes its own compression stroke.
A proper rotary compression tester reads all three faces on each rotor, so six readings in total, and records the cranking speed at the same time. Cranking speed matters because a slow-turning engine reads lower. The readings are then adjusted to a standard speed so they can be compared fairly with Mazda’s figures.
What you want to see is two things: numbers that are above the minimum for that version, and numbers that are close to each other. One low face usually means a worn or broken apex seal on that rotor. Every Mazda 13B rotary engine for sale we ship comes with these six readings, so you know what you are buying.
If a seller only gives you one number per rotor, or uses a normal piston gauge, ask them to test again properly. If they will not, walk away.
Known 13B Problems in Detail
Apex seals
The seals at the three tips of each rotor. They wear gradually and can break under detonation. Low or uneven face readings are the warning sign.
Coolant seals
O-rings between the housings that keep coolant out of the combustion chambers. Overheating damages them. Signs include white smoke on start-up, coolant loss and bubbles in the coolant tank.
Side seals and corner seals
These seal the sides of the rotors. Carbon build-up can make them stick, especially on engines that are always driven gently.
Ignition coils
Weak coils cause misfires and unburned fuel washing oil off the housings. On the RX-8 especially, fresh coils are cheap insurance.
Turbo system on the REW
The FD twin sequential system has a lot of small vacuum hoses and solenoids. Cracked hoses cause boost problems. Turbo seals wear too.
Catalytic converter on the RX-8
Misfires can damage the converter, and a blocked converter chokes the engine.
None of this should scare you off. It is what rotary owners deal with, and it is why you should only buy a Mazda 13B rotary engine for sale that comes with real test numbers.
7 Proven Checks Before You Buy a Mazda 13B Rotary Engine for Sale
1. Get face-by-face compression readings
Six readings, with cranking speed, from a proper rotary tester. This is non-negotiable.
2. Match the version to your car
An REW, a Renesis and an FC engine are all 13Bs, but they are not interchangeable. Get the version confirmed in writing.
3. Ask about overheating history
A Mazda 13B rotary engine for sale from a car that overheated is a risk even if it still runs. Look for signs of heat on the housings.
4. Check the oil and coolant
Oil in the coolant or coolant in the oil points to seal trouble.
5. Check the turbos on an REW
Ask about shaft play and oil in the intercooler pipes.
6. See real photos
You want pictures of the actual Mazda 13B rotary engine for sale you are paying for, not a catalogue image.
7. Get the warranty in writing
Know what it covers, how long it lasts and what you must do to keep it valid.
How We Test Every Mazda 13B Rotary Engine for Sale
- Record the version, engine number and donor car where known
- Compression test on all six rotor faces with a rotary tester
- Check oil and coolant for mixing
- Look for heat marks or discoloration on the housings
- Turn the eccentric shaft by hand and feel for roughness
- Check turbo shaft play on REW engines
- Photograph the engine from every side
- Seal the ports and pack for shipping
More on our process in our guide to tested used engines.
What Comes With the Engine
A complete engine normally includes the front, intermediate and rear housings with both rotors, the eccentric shaft, front cover, oil pan, intake, fuel rails, injectors and the oil metering pump. REW engines can come with the twin turbos and pipework when ordered. Computers and harnesses vary. Your quote lists exactly what comes with your Mazda 13B rotary engine for sale.
Mazda 13B Rotary Engine Price: What Affects It
The current price is on our Mazda 13B product page. That price is for a complete, fairly used 13B-REW. The final number depends on:
- The version, with REW engines costing the most
- Compression readings
- Whether turbos, computer and harness are included
- Shipping method and destination
Clean REW engines have become harder to find, and the price of a good Mazda 13B rotary engine for sale has climbed. Budget for coils, plugs, a radiator and coolant hoses too. Our replacement engine cost guide helps you plan the rest.
Used Engine or Rotary Rebuild?
A rotary rebuild is a specialist job. Done well by a rotary shop, it can give you a fresh engine. Done badly, it can fail quickly. Prices are high either way. A used engine with good face readings is the quickest and cheapest way back on the road. Our guide to remanufactured vs rebuilt engines explains the difference. If you plan a big power build anyway, a good used Mazda 13B rotary engine for sale is still a smart core to start from.
Fitting Tips From the Workshop
- Find out why the old engine failed. On rotaries it is very often heat.
- Fit a good radiator, new hoses, a new thermostat and a new radiator cap.
- Bleed the cooling system carefully. Air pockets are a common killer on the FD.
- Fit new spark plugs and coils if their age is unknown.
- Check the oil metering pump lines and connections.
- On an REW, replace cracked vacuum hoses while everything is open.
- Fill with the right oil and prime the system before the first start.
A rotary-savvy workshop can fit a Mazda 13B rotary engine for sale without drama. If your local shop has never worked on a rotary, it is worth finding one that has.
First Start and Break-In
Once the Mazda 13B rotary engine for sale is in, disable the fuel and ignition and crank it for a few seconds to build oil pressure. Then start it, let it warm up fully and check for leaks. Bleed the cooling system and watch the temperature closely.
Drive gently for the first few hundred miles, but do not baby it completely. Vary the revs, and once it is warm, let it rev now and then. Change the oil early, at around 500 to 1,000 miles.
Living With a Rotary
- Check the oil level often. A healthy rotary uses some.
- Always let it warm up fully. Never start it cold and switch it off straight away.
- Use the revs once it is warm. Rotaries that are always driven gently tend to carbon up.
- Keep the cooling system perfect. Watch the gauge every drive.
- Many owners add a small amount of two-stroke premix oil to the fuel for extra seal lubrication.
- Replace coils and plugs on time.
Look after a Mazda 13B rotary engine for sale like this and it will reward you with plenty of smooth, high-revving miles.
Rotary Swaps and Builds
The 13B is a favourite for swaps into lightweight cars. It is compact and sits low and far back, which helps handling. MX-5 and older RX-7 owners do it often. Some FD owners also convert the twin sequential turbos to a single larger turbo for simpler plumbing and more power. If you are planning a build, tell us what you need. A complete Mazda 13B rotary engine for sale with its harness and computer makes life much easier.
Notes for RX-8 Owners
The RX-8 has a bad name for engine failures, and some of it is earned. But a lot of Renesis engines die from the same few habits: short trips, starting cold and switching off straight away, worn coils and low oil. If you fit a Mazda 13B rotary engine for sale to an RX-8, fit new coils and plugs, check the catalytic converter is not blocked, and get into the habit of letting the engine warm up fully before you switch it off. Many RX-8 owners also fit an upgraded oil cooler setup and keep an eye on the coolant level weekly. Treat it right and the Renesis is a sweet engine.
Signs Your 13B Needs Replacing
- Hard starting when the engine is hot, even with a good battery and starter
- Low or uneven compression on a proper rotary test
- White smoke on start-up and coolant loss with no external leak
- A sudden loss of power with a rough idle after a hard run
- Overheating that keeps happening after cooling system repairs
Send us your test numbers or symptoms and we will tell you honestly whether a Mazda 13B rotary engine for sale is the right fix, or whether it is a coil, plug or cooling issue you can sort first.
For Workshops and Importers
Rotary specialists and JDM importers are some of our regular customers. We can quote several engines at once and ship them together to save on freight. Every Mazda 13B rotary engine for sale in a trade order is labelled with its version, engine number and quote reference, with photos and face readings you can pass on to your own customers. Ask about including computers and harnesses for swap builds.
Worldwide Shipping
We ship to North, Central and South America, the Caribbean, Europe, Africa, the Middle East, Asia, Australia and the Pacific, by sea or air. Every Mazda 13B rotary engine for sale is drained, sealed, strapped down and crated, then shipped with tracking and export paperwork. Our shipping policy has the details.
How to Order
- Send your car and chassis code through the contact page or call +1 (209) 733-0882.
- We confirm the right version and send photos and face readings.
- You get a written quote with engine, extras and shipping listed separately.
- You pay by bank transfer, the only payment method we accept. See our billing terms.
- We ship with tracking and send the documents.
New to buying engines online? Read how to buy a used engine online.
Warranty and Returns
Every Mazda 13B rotary engine for sale we ship comes with a written warranty, with the terms on your quote. See our used engine warranty page and our refund and returns policy.
Why Buy From NJ Global Auto Parts
We test rotaries the right way, give you every face reading, send photos of the real engine and tell you about anything we find. We ship worldwide every week to owners and rotary shops. Learn more about us.
More JDM Engines
Rotary owners often have other JDM projects too. See our Honda B18C guide, our Mitsubishi 4G63T guide and our Nissan SR20DET guide, or shop the Toyota 2JZ. We also sell the Subaru EJ25 and the Honda J35A.
Quick Summary
The 13B is a brilliant engine that needs the right care. Insist on face-by-face compression readings, match the version to your car, fix the cooling system and keep an eye on the oil. Do that with a tested Mazda 13B rotary engine for sale and your RX-7 or RX-8 will be back to doing what it does best.
Frequently Asked Questions
Where can I find a tested Mazda 13B rotary engine for sale?
Right here. Every Mazda 13B rotary engine for sale we ship comes with six face readings, photos and a written warranty.
Is it normal for a rotary to use oil?
Yes. The engine injects oil to lubricate the seals. Check the level often.
Can I put a 13B-REW in an RX-8?
It can be done but needs a lot of custom work. Replacing like with like is much simpler.
How long does a 13B last?
It depends heavily on care. Engines that are kept cool, warmed up properly and given fresh oil often go a long way. Overheated or neglected engines can fail early.
What compression readings should I look for?
On any Mazda 13B rotary engine for sale, you want readings above Mazda’s minimum for that version and close to each other across all faces. We give you the numbers and explain them.
Do you ship worldwide?
Yes, by sea or air with tracking.
How do I pay?
Bank transfer only. Details come with your quote.
Get Your Rotary Running Again
If your RX-7 or RX-8 has lost compression, blown a coolant seal or flooded one time too many, it does not have to stay parked. Send us your car and we will confirm the match, send photos and readings and give you a clear price on a tested Mazda 13B rotary engine for sale, delivered wherever you are.