What Are The Most Common Issues With Mazda Rotary 13B REW Engine?

WVDOT Automotive is reader-supported. This post contains affiliate links. As an Amazon Associate I earn from qualifying purchases.

The 13B engine was initially launched in 1973. It was used exclusively in Mazda’s RX series of vehicles. The REW variant featured a turbocharger, which greatly boosted the engine’s performance. The fact that it was the very first turbo engine to be mass-produced says a lot about it.

Although the engine has rock-solid performance, which was loved by thousands of people and then and is still a top choice for many people today, the engine does have its shortcoming.

The most common ones of them all are:

  1. High Maintenance Requirements
  2. Failure Of The Catalytic Converter
  3. Cracking Of The Turbo Manifolds
  4. Drop-In Engine Compression

As you may have seen, the above problems are ones that should definitely be considered before you buy this engine. This article will be focusing on all of these Mazda Rotary engine problems.

So, let’s get straight into it.

The 4 Most Common Mazda Rotary Engine Problems

This section of the article will focus solely on the problems I outlined in the introduction above. From the causes to their solutions, everything will be covered over here.

So, strap in and enjoy the ride!

1. High Maintenance Requirements

Background

High maintenance is one of those factors that hindered dozens of people from buying this Mazda Rotary engine. The fact that many people get their rotary engines replaced with some other ones states that they really did not want to deal with the high maintenance costs and frequent visits to the workshop.

Reasons

The rotary engine is quite a sensitive one. It needs to be maintained at all times for it to function efficiently and properly. The engine will cause many issues, which were learned by users the hard way.

So, why does the engine have such high requirements? Well, because it is a rotary engine. All rotary engines have extremely high maintenance needs. Users must be aware of that before they purchase it.

How Much Maintenance?

Well, you need to follow a strict schedule to make sure the engine is operating in optimum conditions. After several user reports and research, I have finally created the ultimate guide to follow if you want to keep the 13B engine in pristine condition:

  • Add 1 quart of oil after 2000 miles.
  • Use non-synthetic oil only.
  • Let the engine warm-up and don’t shut it down when it is cold.
  • Make sure the engine is not overheating.

As you can see, the engine overuses oil. That does allow it to get that amazing performance, but the maintenance costs rack up rapidly. The engine also overheats pretty rapidly, making it unsuitable for long trips.

There is a good solution to that problem. You can modify the cooling system to make it more efficient. You have no idea how poorly designed stock cooling solutions generally are.

2. Failure Of The Catalytic Converter

Function

Although most of you may already know the function of this part of the engine, there may be some who don’t. The catalytic converter of an engine converts the harmful emissions produced during combustion into safe gases, which are suitable for release into the environment.

How It Fails

You may now understand what would happen if the converter fails. You are not only exposing yourself to those harmful gases but are causing more air pollution than the legal range. This could get you into issues with the authorities.

The 13B engine uses two converters. Now, the question arises, how do they fail? Well, this is due to the engine overheating, which is a problem I mentioned earlier. The extreme temperature of the engine causes the first converter to burn up, which, in turn, results in the second one getting clogged up.

As both of these catalytic converters become non-functional, there is no way to process those exhaust gases.

Symptoms

As usual, there are some symptoms when the converter of a vehicle is not working normally.

Some of them are:

  • The smell of sulphur coming from the engine.
  • Black smoke coming from under the hood.
  • Engine overheating.

Although the last two symptoms can be caused by a variety of issues, the first one confirms that the exhaust gases of the engine are not being processed. The only way to fix this issue is to get the converters system completely replaced.

Aftermarket converters not only perform better but are also resistant to high temperatures. So, you should definitely buy one when the stock one has reached the end of its life.

3. Cracking Of The Turbo Manifolds

Function

The next problem on this list occurs due to it being a turbo engine. It is not every day that you hear the very feature, which has been designed to improve the performance, is the one causing issues for the engine.

First of all, let’s get the confusion out of the way. A turbo manifold is an exhaust manifold. It’s not a separate part. Its function is to connect the turbocharger to the exhaust system. This allows air to be carried inside the engine.

The Problem

As you may have noticed, the manifold is pretty important because it ensures that the engine temperature is maintained as well as the airflow. So, how does it crack?

Now, this is an excellent question. Well, after a lot of research, I found out that the manifold was not designed to handle rapid changes in temperature. Yes, that’s right.

Many of you may find it surprising, but metal, which is the main choice of material for this intake, can crack easily when it expands and contracts a lot. The intensity of the cracks can vary from being small, hairline ones to large ones, which greatly affect the performance of the engine.

Repair

Although the small cracks will not cause any issue in the beginning, they will become more severe in the future. The reason for this is that the metal will not be able to handle the temperature and the vibrations of the engine.

When the cracks become too significant, you will notice these symptoms:

  • Whistling sounds from the engine.
  • Poor acceleration.
  • The poor boosting ability of the engine.

When you start noticing these symptoms, the only thing you can do is to get the intake replaced. You can expect to shell out around $1000, including the labor costs, to get the job done.

4. Drop-In Engine Compression

We have reached the final issue of this article, which is perhaps one of the most serious ones out of all. Some Mazda Rotary engine owners reported that the engine lost compression.

The Issue

So, why does this happen? Well, there is only one reason for that, and that is the lack of moving parts in the engine. Yes, that’s right that can cause problems too.

Unlike a normal engine that has more than 40 moving parts, a rotary engine only has three. The 13B engine uses metal apex seals which are exposed to wear and tear whenever there is a decrease in engine pressure.

These seals can go bad due to the high engine temperature and the lack of oil. Well, when they go bad, you will definitely lose the engine pressure.

Symptoms

Fortunately, you can catch the problem early and treat it before it escalates too much.

There are some symptoms, such as:

  • Rough idling of the engine.
  • Sudden shutdowns of the engine while idling.
  • Unexpected misfires.
  • Poor acceleration.

As the engine cannot maintain the pressure in the engine, these are the first symptoms you will notice. The power loss is something you cannot definitely miss.

Avoiding The Issue

So, what can you do to make sure that the issue will not happen again? You should make sure that the oil is at sufficient levels at all times and the engine has enough fuel too. As the engine burns one quart every 2000 miles, you need to have a bottle ready to get it topped up.

If the seals are beyond use, then the only thing you can do is rebuild the engine. To replace the seals, the whole engine needs to be torn down, so it is better to get the rebuild done too.

What Is The Mazda Rotary 13B REW Engine?

The rotary engine is not a new one. It came in production, for the first time, almost half a century ago. Yes, you read that right; the engine is quite old. The 13B engine is also the highest-produced rotary engine ever. As is customary for Mazda, it makes sure to honor the people who are credited for the technologies they use.

Well, this engine was part of the company’s Wankel Rotary line, which pays homage to the creator of the first rotary engine, Felix Wankel. There have been many different versions of the engine throughout its lifetime. The engine is still popular, despite it being retired in 2002.

Is The Mazda Rotary Engine Reliable?

This is the first article, out of many, that I have to say that the engine is not reliable. It does not even come close to being a decent-performing one for daily use. No matter how much you care for the engine, there will always be some problems that will lead to you spending money.

The engine can have various different issues, four of which I listed and detailed above. The fact that the engine gulps oil to the point that it needs 1 quart every 2000 miles means that it is not fit for daily driving.

What Cars Use The 13B REW Engine?

The 13B REW is one of the many variations of the 13B engine. There were a total of seven different models. The most popular one is the one that is the center of our discussion, here today, in this article. The REW engine was reserved for the Mazda RX7 only.

The raw power of the engine is a very respectable 255 HP. Some of you might think that this is less, but the engine is also almost 50 years old at this point. The engine started shipping with the 1992 Mazda RX7.

Over the years, there were improvements, and the final version, which shipped from 1999 to 2002, was able to output a very impressive 280 HP.

Mazda Rotary Engine Specs

Cylinder block composition Aluminum alloy
Cylinder head composition
Fuel Gasoline
Fuel injection type Carburetor
Arrangement Rotary
No. of chambers Two rotors
Valves in each cylinder
Valvetrain layout
Bore
Stroke
Displacement 1.3L or 1308 cc
Internal combustion engine (Type) Naturally articulated, Turbocharged
Compression ratio 9.0:1
Power 135 – 280 HP
Torque 130 – 280ft.lb
Weight of engine oil SAE 5W-40
The capacity of engine oil 3.3 quarts w/filter
Firing directive
The interval between oil change 7500 miles (12000 km) or 7 months

The Benefits Of Choosing Mazda Rotary 13B REW Engine

As this article aims to enlighten you with the 13B REW, rotary engines pros and cons, let’s talk about some of the benefits of owning this engine:

  • The engine has very high RPMs, much higher than traditional piston engines.
  • Due to the lack of moving parts, there is little to no vibration when the engine is running.
  • You will not have to worry about issues such as knocking.
  • The engine will not break up in case there is a seizure.
  • The design of the engine is very simple, with only three moving parts.

FAQs

How Long Do RX7 Rotary Engines Last?

Even with proper maintenance, the engine is rated to last only 150000 miles. This is less than half of many piston engines, which makes the engine a definite choice for many people. If not maintained, then you can expect to run into severe issues in a short while.

Is Rotary Better Than Piston?

The first thing you need to know is why they are called rotary engines. The answer is in the name as all parts of the engine rotate. Rotary engines are lighter than their piston counterparts. This is an advantage. I am afraid it ends there. A piston engine has lesser emissions and is more reliable than the other one.

How Often Do I Have To Rebuild A Rotary Engine?

You are definitely not going to like this answer. A rotary engine needs to be rebuilt every 80000-100000 miles. This is considerably less than a piston engine. Even if not, the engine will last 50000 more miles.

The design is severely flawed. Although users appreciate the performance, they don’t want to deal with this issue, which will end up costing them a lot.

Conclusion

If you were looking for Mazda Rotary engine problems, then I can assure you that you won’t find an article that is more detailed than this one. From the issues to their repair options, everything has been covered to make sure you make the correct decision and don’t regret it later on.

The rotary engine is interesting. During my course of writing this blog, I have never come across an engine that is as unreliable as this one, and people still choose to buy it. If you didn’t know, the RX series by Mazda is extremely popular. But, my final advice is to steer clear from buying this engine.

Resource:
1. https://tuningpro.co/mazda-13b-rew-engine-problems/