Imagine my surprise of overlooking this thread since it's inception and I just went and read every single post!

Please excuse me while I go pick up the one bazillion pieces of my brain from the explosion!

Good thread and some rather good theories.

Summation....damned if you do and damned if you don't.

 

the rotary is what it is.
Kinda like when i first discovered my *****---i thought "Ok i have this thing, I really like it, but now what do i do with it, just enjoy it while I can?"

I will probably be banned for saying that.
OD

 

Getting back to Eric's theory on the side seal springs. Besides upgrading the materials has anyone looked at changing the design to allow for something with more meat and less movement? more metal and less motion would increase the life of the spring at the same temperatures. Of course upgrading the material is still probably in order if it's underdesigned for the temps. Something like a belleville washer with a nickel alloy in it would do a better job. Nickel's not very springy though and I have no idea how to package it on the rotor sides. Or as Jeff suggested a high chrome stainless steel may be the ticket.

http://en.wikipedia.org/wiki/Spring_%28device%29#Types

 

Even with this information below, me thinks the smart Renesis Engineers have figured out that the current springs works best. Interesting to think about a stronger spring for our type of environment. Thanks for the idea Shaun

http://www.smalley.com/wave_springs/expanders.asp

http://www.smalley.com/engineering/materials_table.asp

 

Reminds me of that Steve Martin movie "The Jerk" when he discovered his "Special Purpose".

Okay, so now back to the thread, I see there are already a couple more posts I gotta go catch up on!

 

Enjoyed some beer while reading through the entire thread. And I have to admit that the impression of the RX-8 is quite different on this "American" forum than it is over here. I think there's a bit over 150 RX-8's in Norway. I've heard of a couple 2004 automatic (standard power) models and one 2004 high power having replaced engines. I've had personal contact with perhaps 15-20 RX-8 drivers and had info from some 8-10 more, and bar some coil issues I pointed towards the BHR kit I haven't heard of any serious problems or engine replacements. That's why this sounds strange to me. But I don't KNOW, maybe 50 of the drivers I haven't talked to had their engines replaced or maybe they have horrible compression now.

But the fact that this is a 45,000 to 65,000 dollar car here I think it's odd that they don't find the national forums if they have problems. I may do some research on the matter.

 

That's exactly why I want one! Every time I read about it, I hear nothing but good reviews on how it drives. Threads like this are kind of scary to prospective owners though...

 

This guy looks like your candidate:

INCONEL5 ALLOY 718
AMS-55961 180,0002 102,0002 1300 29.6 X 106

Nice stuff Eric. Also interesting to note that it's modulus of elasticity is about the same as that carbon and stainless steel. Very clever bit of metallurgy there. Bravo!

Inco -718 was the go-to stuff when I was in gas turbine design. Although the bosses would always roll their eyes at us because it was pricey. "again with the Inco-718 guys." "Well if you want it to last and not melt...yes."

 

Don't let them bother you, get a good late RX-8 as possible ..

For "normal" owners there is absolutely nothing that is said in this thread that has not been discussed many, many times before, many years ago.

Just like there is nothing new in technical information that Mazda does not know or already has not tried to address, the only latest upgrade in S2's engines has been the Side Seal Spring, and used in all new RENESIS rebuilds from about now, time will tell if it makes any reliability improvement.

You wont be disappointed, just get a good one.

 

That's why I was trying to get an 06. I really want Winning Blue, and the last year they made that was 06... I figured as an 06 it would have spent the least time (or none, can't remember flash dates) driving with the low oil consumption of the early models.

 

There are so many possibilities on the side seal failures, and the engine failures in general. Here are a few things I wonder about.............

The seal is much closer to the edge of the rotor than before...likely causes more exposure to combustion heat from that??

The addition of the extra cutoff seal...does it cut down on the oil lubrication the side seal recieves from oil that used to make it past the oil control rings on the old engines??

Obviously the exhaust heat from the other rotor causes heating of the rotor..

Lower oil pressure...less oil spray into the rotor for cooling??

As far as I am concerned the carbon issue is more of a problem for cars that are street driven. My very small sample size has shown me little to no carbon buildup in my engines that I tracked a lot. The engines that I have seen on non-tracked cars were carboned to crap.

Saying that race car engines and racing are irrelevant to street car failures is crap though. The race environment stresses engines way more than street driving ever will, and racing technology has done nothing but improve street engines in every regard.

ASH....We likely have all read the Mazda documentation that they have released....and quoting it is a waste of time. If you can get some Mazda technical information on the specific failures they are seeing with this engine...post that But it is a bit condecending to post the stuff from the Dealer Highlights manual that is mostly tidbits for the techs who couldn't give a hoot to try and figure this out.....except maybe to have a few buzz words to quote to uninformed owners

 

There's definately corroberation, but there's also a point where the modifications do become irrelevant for a road car - no roadgoing car would benefit from the oil cooler and radiator sizes/hoses/setup that we run for example, you'd never use them to their full extent, and just be lugging extra weight around and have a packaging nightmare to deal with.

Racing solutions can help, but only if extrapolated/adapted to road use, rather than a straight copy

 

For sure.....that's what I love about the internet...things get taken way too literally

If it wasn't for racing...the only thing driving engine design would be emissions That would sure be fun LOL.

 

YES, especially with side exhaust vs pp exhaust ports ... heat is carried with exhaust gases, now that it is no a PP exhaust (when the apex seal was getting battered), we are seeing this issue on side seals. The issue is even greater as they are closer to the edge...

Someone more knowledgeable than I should comment, but I would say yes as well...

Absolutely, also coolant goes front rotor -> rear rotor -> radiator ... so the rear rotor sees warmer coolant and runs hotter in general ...

you also have the transmission right there and it gets warm as well ... possilby warmed than engine bay temps (in front and around the front rotor) when in motion...

This is why rear rotors blow first often...

Also, on the rx8, the rear rotor runs slightly richer to combat this effect.

Not necessarily, it depends on who you ask, but some say the MOP sees atmos pressure. If oil pressure was required, then SOHN adapters would not work?

I'll leave this for someone else to expand.

I do agree in general ... BUT

You just said carbon is only an issue on the street and not in a race environment. This would suggest that we need to consider the street application as fundamentally different than race environment ....

^+1 ... I am fb friends with a dude that works on Rotaries at mazda japan, I will try to hit him up ...

 

Only in terms of solving the carbon problem. The heat and lubrication questions are still very relevant from racing to street applications.

edit: That was a bit harsh. I'd like to keep the discussion constructive.

 

Well it goes from front combustion side to rear combustion side...to rear exhaust to front exhaust to radiator...so that kinda blows that theory

It does? Where does this happen? as far as I know the ECu doesn't adjust the rear trim

I eas talking about the eccentric shaft spray nozzles..not the MOP The MOP on series 1's do not see pressurized imputs..the Series 2 are a whole different system

That is data that I would pay to see Get on that dude

 

I am going to let Eric test out the new spring rates since he has the money and track time to test it. Plus hes got 4 engines sitting in his garage to play with. I would love to see how it turns out though!

 

all good.
Dan the repositioning of the side seal had not been mentioned in this thread. good pick up. I mentioned the new design of the side seal. wedge type now--wedge shaped stuff takes whatever force is applied on the wide part and focuse's that force toward the small side. Ever spit logs for firewood?
Maybe the new shaped side seal is also applying a higher than previous pressure on the spring too?
That wouldnt be good would it?

 

Great input guys. If people take the time to read they may learn a thing or two (or become more confused ) Can anyone give me a visual on the repositioning and changes made to the side seals? I'm having trouble (duh) picturing this in my head. Wedge type?

 

how do you figure?

Use your own example of a wedge splitting firewood. The shape doesnt change the forces involved, it only changes the area over which the force is applied to create a mechanical advantage of sorts. What is the shape of the piece in question where it makes contact with the spring, in comparison to previous shape?

 

From the older 13'bs the renesis side seal is pushed closer to the edge of the rotor.






The side seal itself is a wedge shape versus flat even shape. You cannot put in an older style flat side seal into the renesis rotor it just doesn't fit.

The rotor was designed to have the wedge. I forget the logic behind the wedge but I know it made sense when I heard it.

Sorry I cant find a good pic of the side seal cut itself.

Sorry I am really tired I hope this made sense.

 

the side seal groove is cut in a wedge shape as well as the seal it self. So it would be the same surface area.

 

I hope this helps you!

 

I also found this page for you

https://www.rx8club.com/series-i-tech-garage-22/my-latest-renesis-engine-build-195573/

 

'Have we ALL read it', Really, It appears not to be so, and thanks to Kevin (Dealer Tech) who originally posted the 09 Highlights from MMC a few years back, we would know even less.

Those 'tidbits' correlates and cross reference exactly to what has been renewed, modified replaced or added with Mazda's genuine Parts Manuals....In other words what is said is exactly correct with all vehicle changes.

Perhaps you could suggest or demonstrate what has changed in the Series 2 RX-8's at a mechanical micro level in the 2010 and 2011 models?, as there has been quite a few changes and a few significant ones..

Please, I wait for your response.

Don't want to know, or don't really care...fine.

Condescending that is a bloody laugh, no , please do not stack me in that group as there are enough 'Legends' in this Forum who know way more than what Mazda does and why they get it wrong, they are so successful at what they do and are highly recommended. They are so clever and knowledgeable that they are constantly consulting with Shinji Kanai, Manager Technical Service Department in MMC Japan telling him what is wrong.

You really do tar ALL Mazda Dealers with the same brush?, well not where I come from, perhaps doing it right is the reason why Australia is Mazda best performing market worldwide, with the highest Customer Satisfaction level than ANY other brand of car., WHY?, because repairs are done correctly most of the time, owners are satisfied most of the time. Mazda along with Honda also has the highest loyalty rating of any other brand here, once a Mazda or Honda owner always one.

In contrast to North America the brand has an average experience with owners, perhaps, perhaps because all of the non dealer amateurs who misrepresent car makers, making a quid out of false information, questionable parts, poor workmanship and down right lies to fraud...all installs a great reputation for ANY make of car.

Until MNAO seriously tackles what their Dealers do, HOW they do it, who they employ, how they are trained, etc, etc, nothing much will change.
Mazda will continue to be in the middle of the heap.

Gee it has been shown here just how good Vendors can be at Customer Service, Supply and at an After Sales level...what after sales!.
Some are brilliant, some are just bloody woeful, and treat their bread and butter with utter contempt.

WHY would any sane enthusiast even contemplate a relationship with businesses like this...must like to bend over!

This thread is about Possible NEW Renesis Engine Failure Theory?, theory indeed and everything in between.

Yes, it is all good and forums like ours can be great for informing and "help".