Complete Guide to Rotary Engines

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Complete Guide to Rotary Engines

Rotary engines are a type of internal combustion engine that takes pressure and turns it into rotating motion to produce usable power. Compared to the piston engine, the high rotational speeds of the rotary engine do not produce mechanical stress or vibrations. Rotary engines work in four-stroke cycles, and the central rotors work to cause compression, exhaust, intake, and ignition in the trochoid chambers. The primary difference between a piston and a rotary engine is the way each engine type uses combustion to create mechanical force.


Rotary engine efficiency

The type of rotary engine in a vehicle determines the overall efficiency. Although overall fuel economy is not usually impressive, fuel efficiency is generally better than it is in an equivalent piston engine. Compared to a piston engine with two-thirds more weight, a rotary engine has an equivalent power output.

A piston engine operates at 180 degrees F to fill the combustion chamber. In contrast, the rotary engine operates at 270 degrees F to fill the combustion chamber with greater efficiency.


Rotary engine maintenance

Maintenance is important to maintain a rotary engine and ensure long life. Drivers have to perform certain maintenance tasks on a regular basis for all types of rotary engines. For example, changing the oil regularly is one of the most critical maintenance tasks.

Oil changes

Owners should change the oil every three months or every 3,200 kilometres for turbo rotary engines or every six months or every 4,800 kilometres for general rotary engines. When changing the oil, they need to completely drain the old oil and replace it with fresh oil of the right viscosity. It is also important to replace oil filters at the same time. Rotary engine vehicles used for racing purposes generally require more frequent oil changes.

Other maintenance

Because rotary engines operate at higher revolutions per minute and are smaller than piston engines, they require more frequent inspections to ensure all the parts and components remain in good working order. Preventive inspections allow drivers to quickly address developing issues before they become expensive repair problems. As a basic starting point, drivers should frequently inspect belts and spark plugs. When examining belts, owners should look for issues like marks, excessive tightness, cracks, and glazing on the belt.

It is important to monitor and maintain rotor seals on rotary engines. Over time, leaks can develop in the seals, causing exposure to fuel on both sides. In addition, gaps commonly occur between the trochoid housing and the apex seal, and seal problems can affect the tip, apex, and rotor on an engine.

Finally, owners should conduct frequent checks of the combustion chamber. It is possible to improve emissions and fuel economy with proper maintenance of this critical component along with maintenance of the seals. Otherwise, the inefficient operation of the chamber could lead to emission and other types of engine problems.


Engine applications

Rotary engines are in use in a variety of vehicles, including automobiles, aircraft, and motorcycles. This type of engine is also sometimes present in personal watercraft and go karts. In automobile racing, the Mazda family of racing vehicles commonly uses three-rotor, two-rotor, and four-rotor engine types in their racing vehicles. The vehicles that use these types of engines are adaptable on road courses and oval tracks and compete on various levels of competition.


Rotary engine advantages

Rotary engines have many advantages over other engine types. The common benefits include:

  • High power to weight ratio
  • No reciprocating parts
  • High revolutions per minute
  • Reduced rick of engine block
  • Almost no vibration
  • Weigh less than a piston engine
  • More durable and reliable overall
  • Use a wider range of fuel octanes

Compared to a piston engine, the rotary engine contains fewer parts, and that generally makes diagnosing problems and conducting repairs less complicated. The fewer number of parts also makes the rotary engine lighter and smaller compared to piston engines.


How to buy rotary engines on eBay

Rotary engines are not as common in the 21st century as they were in past decades, but many types of motor-powered vehicles still use this type of engine. Search on eBay to find rotary engine replacements and parts as well as rotary engine vehicles. Use keyword phrases like "rotary automobile engine", "rotary aircraft engine", "rotary motorcycle engine", or "rotary go kart engine" to produce a list of broad results. To examine listings of more specific items, include additional details, such as engine size, in the search parameters. 

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