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Brett_Murphy
Brett_Murphy GRM+ Memberand UberDork
2/27/15 10:20 p.m.

One day I'll do a rotary Miata.

https://www.facebook.com/CJWilsonRacing/photos/a.917510301626350.1073741901.500062800037771/917510398293007/?type=1

NOHOME
NOHOME UltraDork
2/28/15 6:13 a.m.

Nothing against Rotaries or Porsche engines, but to me, both seem like betting against the house when it comes to not experiencing some form of cata$trophic engine failure.

Would it not be easier to just remove the piston rings from the Mazda engine and get the same experience for a lot less effort?

That said, I love engine swaps, and that one is nice. Had the rotary worked out, it should have been the choice of engine for the Miata. However, had Mazda gone that way,I doubt that we would now have a 25 year long history of Miatas.

Mazdax605
Mazdax605 SuperDork
2/28/15 6:56 a.m.
NOHOME wrote: However, had Mazda gone that way,I doubt that we would now have a 25 year long history of Miatas.

Why do you say that when we had around 25 years of the RX-7, and way more than 25 years of rotary production? I don't understand the bad rap these engines get.

MrJoshua
MrJoshua PowerDork
2/28/15 8:06 a.m.
Mazdax605 wrote:
NOHOME wrote: However, had Mazda gone that way,I doubt that we would now have a 25 year long history of Miatas.
Why do you say that when we had around 25 years of the RX-7, and way more than 25 years of rotary production? I don't understand the bad rap these engines get.

RX8's having very frequent engine failures is giving people unpleasant feelings about the rotary.

Mr_Clutch42
Mr_Clutch42 Dork
2/28/15 8:18 a.m.

Engine swaps are cool, but if it were my weekend/auto-x car, I would do a V6 swap instead.

alfadriver
alfadriver UltimaDork
2/28/15 8:22 a.m.
Mr_Clutch42 wrote: Engine swaps are cool, but if it were my weekend/auto-x car, I would do a V6 swap instead.

Last gen RX7 + good V6. that would be fun.

There was a rumor of a Duratec V6 in one, but I don't know if that car was ever finished. Done to see if a Lincoln based off of the RX7 would have been a good idea. And this pre-dated the Lincoln Miata by about 5 years.

Knurled
Knurled GRM+ Memberand UltimaDork
2/28/15 8:26 a.m.
NOHOME wrote: Nothing against Rotaries or Porsche engines, but to me, both seem like betting against the house when it comes to not experiencing some form of cata$trophic engine failure.

In sixteen years of playing with rotaries, I have never once blew a connecting rod out or burned a valve or spit a valve shim out of the bucket or bent a pushrod or hammered a keeper through the retainer or dropped a seat or burned through a piston or flattened a cam lobe or broke a timing chain or...

I set the clearances right, put the engine together, then proceed to wail for a very long time. I used to have coolant seal problems but solved those by being less cheap.

Giant Purple Snorklewacker
Giant Purple Snorklewacker MegaDork
2/28/15 8:33 a.m.

RENESIS? Isn't that the Chinese knock-off of the thing that brings Spock back to life?

JtspellS
JtspellS SuperDork
2/28/15 9:45 a.m.

This engine is the later S2 engine with many reliability mods from the factory so they are now using "the best of the breed" so reliability should be the least of the issues just as long as they can keep underhood temps down.

Trans_Maro
Trans_Maro UberDork
2/28/15 9:54 a.m.

In reply to Knurled:

I've never done any of those things and all I own are piston engines.

Maybe there is a variable in your experiences that you're not considering.

Swank Force One
Swank Force One MegaDork
2/28/15 10:13 a.m.

I would be all about this. I bet it scoots pretty good.

Mr_Clutch42
Mr_Clutch42 Dork
2/28/15 12:46 p.m.

In reply to JtspellS: That's really good them. I would still gripe about low torque and low mpgs, though.

JtspellS
JtspellS SuperDork
2/28/15 12:48 p.m.

MPG yes, but the lack of torque is simple to cure, stop being lazy and downshift a gear or 2.

You V8 people

pres589
pres589 UltraDork
2/28/15 12:51 p.m.
alfadriver wrote: ... And this pre-dated the Lincoln Miata by about 5 years.

The what??

Mr_Clutch42
Mr_Clutch42 Dork
2/28/15 12:56 p.m.

I'm also a straight-6 guy.

http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/e36-328-in-over-my-head/84578/page1/

Knurled
Knurled GRM+ Memberand UltimaDork
2/28/15 2:48 p.m.
Trans_Maro wrote: In reply to Knurled: I've never done any of those things and all I own are piston engines. Maybe there is a variable in your experiences that you're not considering.

Oh, I started playing with rotaries because I was tired of looking at the insides of my engines without requiring the use of tools.

Knurled
Knurled GRM+ Memberand UltimaDork
2/28/15 2:51 p.m.
JtspellS wrote: MPG yes, but the lack of torque is simple to cure, stop being lazy and downshift a gear or 2. You V8 people

It's funny how people white and bleat about having to have a manual transmission yet they also seem to be totally against actually using the thing

My RX-7 makes me pissed off if it gets less than 20mpg. I normally see 23-24 in mixed driving and 29-+ on open flat road. I was fuming when it was barely getting over 16mpg when towing to Omaha last year, apparently the tire trailer sucked all the fuel economy out.

In contrast to the Volvo I've got, which makes a lot less power, has slightly more torque, and the last three fill-ups I did had me right at 15mpg. So, er, hooray rotary fuel economy?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
2/28/15 4:23 p.m.

If you want a Renesis Miata, start with an NC. The RX8 front subframe bolts in and brings the rotary with it.

Now all you have to figure out is the electronics.

NOHOME
NOHOME UltraDork
2/28/15 4:46 p.m.
Knurled wrote:
NOHOME wrote: Nothing against Rotaries or Porsche engines, but to me, both seem like betting against the house when it comes to not experiencing some form of cata$trophic engine failure.
In sixteen years of playing with rotaries, I have never once blew a connecting rod out or burned a valve or spit a valve shim out of the bucket or bent a pushrod or hammered a keeper through the retainer or dropped a seat or burned through a piston or flattened a cam lobe or broke a timing chain or... I set the clearances right, put the engine together, then proceed to wail for a very long time. I used to have coolant seal problems but solved those by being less cheap.

If you HAD broken any of those, I would be surprised. You should read the manual for the rotary engine...the reason you have not broken any of those parts is because rotaries do not have those parts.

For the record, I cant recall when I have had any of those parts fail over 40 years of driving, and not for a lack of trying.

Lets talk about the apex seals that by themselves are more complicated and failure prone than any component in a reciprocating piston engine.

And yes I will concede that an educated enthusiast can keep a rotary engine alive in the same way that I can keep a 1967 MGB running, but lets be honest: the average civilian (especially the lumpy version of the species) does not stand a chance.

Knurled
Knurled GRM+ Memberand UltimaDork
2/28/15 5:01 p.m.
NOHOME wrote: but lets be honest: the average civilian (especially the lumpy version of the species) does not stand a chance.

Agreed. Rotaries do not tolerate abuse. Abuse in this case is things like idling around, spending their entire life below 1/3rd throttle, short warmup cycles... more or less the way you'd treat a Corolla.

Which is a somewhat ironic analogy, because I remember a lawsuit where a guy killed a Corolla by running it out of oil shortly after an oil change and inspection was done. The car lived its whole life in a downtown urban area, and it died when it was taken onto a long highway trip for the first time in its life. Theory: Cylinders had a layer of carbon/varnish above the rings, running at higher speeds made the pistons swing a bit higher, scraping the varnish into the rings, causing them to stick, causing unprecedented (and unexpected) oil consumption that resulted in engine failure after it ran itself out of oil.

Of course, I always eliminate the OMP on rotaries and premix yummy 2-cycle oil at rates far higher than the Internet tells you to do. The Internet gets a lot of things wrong. Anyway, I blame the RX-8's problems on the X-Men movie because a bunch of dimwits wanted to buy Cyclops' car without understanding what it was they were buying.

...and the anecdote about the Corolla made something click in my head, my Volvo used to blow the dipstick out when I first got it, but now that I've had it for 5,000mi, it no longer does this. The PO must have been a weenie

Fueled by Caffeine
Fueled by Caffeine MegaDork
2/28/15 5:11 p.m.

How is an apex seal complicated? Its basically a flat piston ring with a spring behind it. IT does the work of three or two devices Inside a piston engine. If anything it's a more simple device that serves multiple purposes. Let's not get into silly comparisons here. There are equally stupid engineering decisions on bothe sides of the fence.

mndsm
mndsm MegaDork
2/28/15 5:19 p.m.
Keith Tanner wrote: If you want a Renesis Miata, start with an NC. The RX8 front subframe bolts in and brings the rotary with it. Now all you have to figure out is the electronics.

Does this mean that the mzr equipped nc sub bolts into an rx8? I have a wonderful idea.

Swank Force One
Swank Force One MegaDork
2/28/15 5:36 p.m.

There's a disi rx8 or two overseas.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
2/28/15 5:49 p.m.

Yup, I've spoken to a number of folks who have MZR-powered RX8s.

Brett_Murphy
Brett_Murphy GRM+ Memberand UberDork
3/1/15 9:50 p.m.

To me, an MZR powered RX-8 would be fun only if you added boost.

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