The Rotary engine isn’t “delicate” per se; it’s simply quite different and requires knowledge to properly maintain. Face it, piston engines have been developed to the point that most people just
forget about them and simply expect them to work. Rotary’s OTOH, only haveMazda backing them for automobile use and only produce a few thousand a year.
The three main maintenance issues with all automotive engines are the same;Carbon and varnish deposits, lubrication, and cooling.
Carbon & varnish do build up more quickly in a rotary, mainly on the cups of the rotor face and around the exhaust ports. Carbon can be more damaging to a rotary because it can damage the apex and side seals of the rotor, or even “carbon lock” the rotor (where a piece breaks off and acts like a door stop against an apex seal, completely preventing movement).
Luckily, carbon and varnish are easy to burn off. Simply rev the heck out ofthe motor once in a while. Rotary engines can be taken to red line and stay there with very little bad effects, unlike a piston engine. Rotary’s are often used for light aircraft and the motor can run for extended periods at high RPM. A Redline a day keeps the mechanic away.
Lubrication of the Rotary is done very differently from a piston engine. The crankshaft (properly called an “eccentric shaft” in a rotary) and its bearings are lubricated by internal ports that draw oil from the pan. The interior of the motor lubricates the apex and side seals via the Oil Metering Pump (OMP), which is similar to a 2-stroke motor in that it actually injects oil into the combustion chambers.
Because you’re actually consuming oil in this process this requires you to check you oil level frequently (every 2 weeks or so for normal driving). Also, it’s a very good idea to change your oil more frequently (every 3000 miles) to keep the oil clean. Mazda requires that you use regular oil in the RX8.more info found in https://www.cars.com/articles/2012-2015-mazda3-mazda6-and-mazda-cx-5-transmission-issues-1420681693085/
Synthetic oils are not recommended as they are designed to deter burn-off and you want an oil that WILL burn off when injected into the combustion process. Actually the better way to lubricate the rotary is to separate the engine oil supply from the injected oil supply. Then you can use a 2 cycle motor oil for injection, which is far better as it is DESIGNED to burn off cleanly. Of course changing to this system will void your warranty, even if it is better.
Some folks add a little extra protection by mixing a between 4 – 8 ounces of 2 cycle motor oil with their gas.
If there is one area that may cause a rotary to be considered
“fragile” it’s in the cooling department. NEVER overheat a rotary.
Doing so will very likely cause one or both of the rotor housings to warp and essentially kill the motor.
With all this said, the Renesis rotary engine is a VERY good motor. Reports of them being fragile is mainly due to the fact that many people who buy the RX8 have no clue on how to properly maintain the engine. The majority of engine failures have been in automatic transmission models in areas of heavy traffic and high temperatures.
Most auto-box drivers drive too sedately for this car. They would never think of giving the motor some revs, so the motor carbons up. High RPM’s also help lubrication by injecting more oil. Since these people putter around or sit for extended periods in slow moving traffic they were running into lubrication issues. The lube issues have been addressed in new PCM/ECU programming.see this link here!