The Ultimate Guide to Buying a Rotary Engine

The rotary engine, celebrated for its unique design and performance characteristics, is a fascinating alternative to traditional piston engines. With its compact size, lightweight construction, and high power-to-weight ratio, the rotary engine has captivated automotive enthusiasts and engineers alike. Whether you are a racer, a car enthusiast, or simply looking for a reliable engine for your vehicle, understanding the different types of rotary engines and their applications is crucial for making an informed purchase. This guide will cover everything you need to know about buying a rotary engine, including comparisons, specifications, and insights into top manufacturers in the market.

Comparison Table of Rotary Engine Types and Applications

Understanding Rotary Engine Design

Rotary engines operate on a fundamentally different principle than traditional piston engines. Instead of using reciprocating pistons, they utilize a triangular rotor that revolves in an epitrochoidal motion within a housing. This design allows for fewer moving parts, resulting in a lighter and more compact engine. The simplicity of the rotary engine also contributes to its high power output relative to its size, making it an attractive choice for performance applications.

Key Components of a Rotary Engine

1. Rotor: The main component that converts fuel into mechanical energy.
2. Rotor Housing: The casing that contains the rotor and provides the necessary sealing.
3. Eccentric Shaft: Converts the rotary motion of the rotor into usable power.
4. Apex Seals: Ensure a tight seal at the tips of the rotor, crucial for maintaining compression.

Advantages of Rotary Engines

• Compact Size: Easier to fit in various vehicle designs.
• High Power-to-Weight Ratio: More power with less weight compared to traditional engines.
• Smooth Operation: Fewer vibrations due to continuous power delivery.

Disadvantages of Rotary Engines

• Fuel Efficiency: Typically less fuel-efficient than piston engines.
• Maintenance: Requires regular upkeep to maintain optimal performance.
• Emissions: Historically, rotary engines have faced scrutiny for higher emissions.

Types of Rotary Engines

1. The 12A Engine

The 12A is a classic rotary engine configuration known for its lightweight and compact design. It is commonly found in older Mazda models like the RX-2 and RX-3. The engine typically produces between 100 to 130 horsepower, making it a popular choice for retrofits and restorations.

2. The 13B Engine

The 13B is one of the most recognized rotary engines, powering the iconic Mazda RX-7 and RX-8. With power outputs ranging from 150 to over 300 horsepower, it is favored for performance builds. Various tuning options, such as street porting and bridge porting, allow enthusiasts to customize their setups.

3. The 20B Engine

The 20B is a three-rotor engine that offers significantly more power, making it suitable for racing applications. With outputs of 200 to over 400 horsepower, it is often used in high-performance builds and is capable of competing at high levels in motorsports.

4. Wankel Engines

Named after their inventor, Felix Wankel, these engines can vary in design and configuration. They are often utilized in experimental vehicles and are noted for their innovative designs that can produce high horsepower outputs.

5. Rotapower Engines

Rotapower engines are designed for applications in both aviation and automotive sectors. They are known for their versatility and efficiency, making them ideal for various specialized tasks.

Buying a Rotary Engine

When considering the purchase of a rotary engine, several factors must be taken into account:

1. Purpose

Identify your primary use for the engine. Are you building a race car, restoring a classic vehicle, or looking for a daily driver? This will significantly influence your choice of engine type and modifications.

2. Budget

Rotary engines can vary widely in price. Custom builds from reputable manufacturers like Pettit Racing and Rotary Resurrection can range from $4,500 for basic rebuilds to $20,000 or more for high-performance specifications.

3. Manufacturer Reputation

Consider the reputation of the manufacturer. Established names like rotaryengine.com and freedom-motors.com offer extensive experience and proven performance in rotary engine builds.

4. Technical Support

Choose a manufacturer that provides ongoing support and guidance. Brands like LiquidPiston are known for their innovative engineering and customer service.

5. Availability of Parts

Ensure that replacement parts and tuning options are readily available. Companies like RotorSports Racing and SR Motorsports offer a range of aftermarket parts that can enhance performance.

Technical Features Comparison Table

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Conclusion

Purchasing a rotary engine involves understanding its unique design, performance characteristics, and the specific requirements of your project. Whether you opt for a classic 12A or a high-performance 20B, ensuring you select a trusted manufacturer is vital for achieving your desired results. As the rotary engine continues to evolve, innovations from companies like LiquidPiston and SR Motorsports keep pushing the boundaries of performance and efficiency, ensuring that this remarkable engine design remains a popular choice among enthusiasts.

FAQ

What is a rotary engine?
A rotary engine is an internal combustion engine that utilizes a triangular rotor moving in an epitrochoidal motion to convert fuel into mechanical energy, differing fundamentally from traditional piston engines.

What are the main advantages of a rotary engine?
The main advantages include a compact size, lightweight construction, high power-to-weight ratio, and smoother operation due to fewer vibrations.

What are the common applications of rotary engines?
Rotary engines are commonly used in cars (like the Mazda RX-7), experimental aircraft, and various racing applications due to their performance capabilities.

How much does it cost to buy a rotary engine?
Costs can vary significantly, with prices ranging from $4,500 for basic builds to over $20,000 for high-performance custom engines.

What types of rotary engines are available?
Common types include the 12A, 13B, 20B, Wankel engines, and Rotapower engines, each suited to different applications and performance needs.

Are rotary engines fuel-efficient?
Generally, rotary engines are less fuel-efficient than traditional piston engines, often due to their design and operating characteristics.

How do I maintain a rotary engine?
Regular maintenance includes checking and replacing apex seals, ensuring proper lubrication, and monitoring for any signs of wear or damage.

Can I find replacement parts for rotary engines?
Yes, many manufacturers like Pettit Racing and Freedom Motors offer a wide range of replacement parts and performance upgrades for rotary engines.

What performance modifications are available for rotary engines?
Common modifications include porting, turbocharging, upgrading seals and bearings, and enhancing cooling systems to improve power and reliability.

Where can I buy a rotary engine?
You can purchase rotary engines from specialized manufacturers and retailers such as rotaryengine.com, rotaryresurrection.com, and SR Motorsports.