Mazda RX7 13B Rotary Engine Rebuild

For those of you who do not know what a rotary engine is, picture an engine that runs off of triangular objects that some refer to as Doritos. Then think about the fact that there are multiple cars and some unmanned air vehicles that use that engine to run. The engine you are picturing is called the Wankel rotary engine. “The rotary engines occupy a niche segment of research that has only seen mass production in automotive application developed by the Mazda Company with Wankel-type Renesis engines.” (Alexandru-Catalin et al 93). The Wankel rotary engine is an “internal combustion engine with rotors instead of pistons, invented in the 1950s by German engineer Felix Wankel” (Philip’s). The unique design of the Wankel rotary engine has multiple advantages as well as disadvantages. I will explain some more about the engine itself and then talk about how much fun I had taking my engine bay apart, having the engine rebuilt, and now having an RX7 that runs right.

I get to show off my love for this car and be festive with my new sweater from Tool and Dye Designs 😍 Cody has one too with a Nissan 240sx! They are our favorite sweaters. Super soft on the inside while being nice and warm. What more can you ask for? We wore them to our work sweater party. We wear them to the gym. We plan to wear them   To the Ugly Sweater Party we our hosting next weekend. And honestly, we will probably wear them all winter before they’re cute, comfy, and warm ❤️

Mazda RX7 Ugly Christmas Sweater9EF86E77-427E-4046-969D-B707CFD0D0A4

“The idea for a rotary engine – which achieves … intake, compression, combustion, and exhaust, while rotating – came to Wankel when he was a teenager. He dreamed he had driven to a concert in a car he had designed that was powered by a new type of powerplant that was half-turbine, half-reciprocating engine. It was the beginning of his career in combustion engine design.” (Scoltock 7). The Wankel rotary engine is a very simplistic design. The outer oval that surrounds the internals of the engine is called a housing. The Doritos mentioned earlier are actually triangle objects called rotors. These rotors spin on bearings that rotate on something called the eccentric shaft. As the rotors spin inside the housings, it passes by an intake port and pulls air into the housing. That air fuel mixture is then compressed to ignite the spark plugs. Lastly, the air escapes through a different port called the exhaust. “The first series application of the engine was in the NSU Spider in 1964” (Scoltock 7). Some individuals believe that in the future Wankel’s “work could help to bring more electric vehicles to the roads” (Scoltock 7). “Audi’s Al e-tron concept vehicle uses a 75kW electric motor and a 12kWh lithium-ion battery linked to a 245cc rotary engine located under the trunkfloor.” (Scoltock 7).

This unique design does bring some advantages to the table. “Felix Wankel was convinced that rotary combustion engines offered smoother operation, improved packaging and in some cases a better power-to-weight ratio than more established technologies.” (Scoltock 7). Because of the simplistic design, they do not have as many parts as conventional engines. This engine having a smaller amount of parts makes it less expensive to manufacture. The engine being so lightweight makes it easier to work on and work with as well. To put this in perspective, a rotary specialist located in Indiana by the name of Chris Sanders has seen a Wankel rotary 13B engine dropped off in the front seat of a Honda Delsol. Another great thing about the Wankel rotary engine is there is less reciprocating mass and less moving parts that allow it to hold higher rpms. This gives it the ability to have more air flow which leads to more horsepower.

Even though the advantages are fantastic, there are some disadvantages as well. Some would say a disadvantage is the gas mileage. This being a disadvantage depends on the individual and what they are using it for. Unfortunately, the Wankel engine’s biggest “downfall, according to Robertson, was that the engine was insufficiently sealed to prevent fluids from leaking and to control emissions.” (Leopold 1). The seals are not always reliable and this is often what causes the engine to be rebuilt so early. More often than not Wankel rotary engines need rebuilt more frequently than piston engines. One hundred thousand miles between rebuilds is considered a long time.

Although these engines are not as popular as piston engines, it has been successful enough to become a niche market. Some of the advantages of the Wankel rotary engine are that it has the simplistic design that contains few parts, a lightweight design, smoother operation, improved packaging, in some cases a better power-to-weight ratio, and the fact that it can hold higher rpms which leads to more horsepower. The disadvantages, unfortunately, are low miles per gallon, unreliable seals, and frequent rebuilds. When it is all said and done, the Wankel rotary engine has both advantages and disadvantages and is preferred by some while not so much by others. Ultimately, this simplistic and interesting design of the Wankel rotary engine is definitely unique.

This was mine and my boyfriend’s first big thing we decided to tackle together. We had only been together a few months and took on a very stressful project together. It went amazing! I wish I still had the before and after pictures of the building we had to clean out to be able to even start. This was a two day super dirty task in itself.

Before the engine came out:

RX7 Engine Rebuild

After the engine came out:

RX7 Engine Rebuild

Banzai Racing was absolutely amazing with the rebuild! They have website which they post pictures on for you every step of the way. I cannot day enough good things about the owners, company, and customer service ❤️


Banzai Racing 13B Engine Rebuild

The new pretty engine:

Banzai Racing Rebuilt Rotary 13B Engine


We decided to go with the EXEDY Stage 2 Cerametallic Clutch Kit 10900 and bought it from Banzai Racing. 


New Clutch and Rebuilt Engine is in!!

13B Rotary Engine Rebuild

It is coming together 🙂

Mazda 1993 RX7IMG_1117 (1)

It started!

Mazda RX7 13B Engine Rebuild

We are on the road 🙂

1993 Mazda RX7





Alexandru-Catalin, Munteanu, and Buzbuchi Nicolae Stan Liviu-Constantin. “ROTARY INTERNAL COMBUSTION ENGINES.” Universitatii Maritime Constanta. Analele, vol. 15, no. 21, 2014., pp. 93.

Leopold, George. “Rotary engine revs for comeback.” Electronic Engineering Times, no. 1454, 2006., pp. 1-1,18.

Scoltock, James. “Felix Wankel.” Automotive Engineer 37.4 (2012): 7-8. Academic Search Premier.

“Wankel Rotary Engine.” Philip’s Encyclopedia, Philip’s, 2008. Credo Reference,