Whats so bad about Rotarys???

[Nismo]

As you all might have noticed I am planning on throwing a Rotary engine (most likely a 13b second gen) in my lil guy (miata). But I keep hearing all these bad stuff about those engines. Honestly whats so bad about them. They spit out juice dont they. I mean they are pretty fast right??? From what I have heard is that they overheat and at times people have problems with the rotors. So what else is there.

P.S.
If you guys want to see how My car looks like go to www.autotrader.com . Go to used cars. Make is Mazda, Model is MX-5. Price is 3,500. to make it easier put in zip code 91786. The blue one is mine. Let me know what you think.

[hachiroku-fc3s]

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[Ghost of Duluth]

K here's the lowdown on the Rotary from my own experience and tainted perspective.

The first gens are great cars. They will run forever given the right attn meaning oil, coolant and tune ups.

Second gens. Also a great engine. Will run forever and still easy to maintain. Great rpm range and easy to predict power curve make them great engines to learn with. The turbo is also a very stable platform to learn with. Tends to get out on you in the beginning until you figure out the turbo.

Third gens. Here is where all the problems begin. Cooling is a MAJOR problem with these motors. The twins on the side of the engine cause many headaches. They are extremely picky and prone to grenading. Easy to overheat without proper cooling upgrades. Hard to tune also and alot of peoples problems come from improper tuning. Unlike piston engines, you cannot just bolt a bigger turbo on and go. Rotaries require extensive tuning and someone very knowledgable with them. Unfortunatly those people are few and rare. Once you overheat one and see any extra smoke, even the sightest amount, your cooked. Reminds me of a line from the Crow. "There ain't no coming back, there just ain't no coming bac". Once it's done, it's done. No chemicals ro quick fixes.

This applies to all rotaries. They are extremely refined engines, meaning that they have very little tolerance for not doing the right thing. Also if you do screw one up, it's usually an exchange only. No rebuilding. Super hard to find anyone to rebuild it and usually not cost effective unless you are doing it yourself.

Thats my take. A rotary in a Miata is neato. Seen em done. They aren't that easy of a swap from what I have heard but cool in the end.

[DriftingShadow]

Rotarys are great just work on the cooling and they rule!

[driftfreak]

no problems with my motor...but i did fry the exahust due to high EGT

[ProjectD]

What's so bad about rotaries?

1-It's super reliable, 2- only 3 moving parts, 4-Best power to weight ratio...err wait that's the good things.

Well I did the inpossible, at least thats what everyone said. i bought an FC for 650$ that didn't run that had 201,000 miles,but cranked.

Now, with the very same original engine, it runs and i spend under 500 to get it running and what it is now. It has more power than my old SOHC 240SX and has better balance. the only thing is remembering to change oil....alot.

[Feint]

If you can pull off the swap,more power to you.The size of the engine and its output is remarkable.Throw that into a Miata,already a great platform that is severly overlooked,you've got one hell of a car.Plumbing would have to be custom,but cool nonetheless.

[HATE_ME_NOW]

from what i've heard, when u rebuild a rotory u have to have the rotary itself balanced? is there truth to this? and if so what entails in doing this?

[driftxtreem]

Ghost pretty much sumed it all up for ya. Depending on the application like drift you might want to do a rebuild on a 3rd gen before you boost the hell out of it. Put in thicker Apex seals. Maybe a nice street port as well. In the stock form you have enough power to learn with but when you get beter you will find it lacking a little. My 3rd gen was ok with TT and .9 bar boost but I was also spinnin 19". I am still working on the 20B conversion and cant wait to see the power this thing puts out.

[spooln7]

Well rotaries aren't that bad I haven't really had to many problems with my FD, and alot of my other friends haven't either, just take care of the motor and always look at the small things because those ended up being what cause the problems. I also agree with what ghost said, well said.

[Ex-Cat]

Hey Ghost, what would you say about a third gen if it were left stock and never driven hard?

[Secret_Agent_86]

Build a rotary and not drive it hard? Now that would be a problem.

The only real problem with rotaries is that they are very efficient; therefore they produce a lot of NOx and heat. Of those only heat a problem from our perspective. Also, it is a little hard to find a good place for the ports, but again, that does not concern the likes of us.

One thing to consider, when you remove the Miata’s fairly heavy motor and replace it with a small, light 13b the weight balance will shift dramatically rearward. This may upset the Miata’s legendary balance if you don’t remove an equal amount of weight from the rear.

[Nismo]

Thanx ghost and everyone else. There was this guy that I once met at the Irwindale speedway. They have drag evey thursdays nights. Anyway that guy has his own shop and also has a RX-7. That guy was telling me that his engine had 3 rotars insted of just 2. He never drove it on the street cuz it would overheat in a matter of minutes. He would just throw it on his tralier. Hual it to Irwindale. Whoop everyone and then just take him and his fame home.

[Ex-Cat]

Secret Agent, I was talking about if I were to come across a third gen owned by a middle age woman. If the problems that people talk about with rotaries are just regarding driving it hard or the design of the motor itself.

[driftfreak]

that and jack stands are a factory option
j/k