rotarygod

Since you weren't at sevenstock and didn't actually hold a Renesis housing and actually feel and see the side seal impact mark for yourself like several of us did, you have no idea what is going on. Sorry to be so harsh but that is why the thread is still alive. There is an issue. Where and when it is caused is what we have yet to learn. We still don't know if it is a problem with every engine or just those under forced induction. I don't know why it would make a difference though.

86rx7

We dont know how long it will take, but it will probably pretty much stop once the seal and housing are rounded off enough to not cause a problem anymore. You probably wont notice it, it would be more noticable in the low rpm ranges/idle/starting than the high, and would probably only really affect peak hp by less then 10 hp. This will not cause the motor to quit working. You can still expect 150-200k+ miles out of it.

For thoose who think there is no problem, I, rotarygod and Mr port and polish have all ported motors, and know the implications of opening the port earilier, and what modifications must be done to the port to prevent this from happening, modifications that are not present on the renn plate.

Here is a website, which is about a completly differnt subject, but it shows the leading edge of the side seal scribed on the housing, you can see how the renn secondary ports would intersect this line.

http://www.mazdatrix.com/sccaportrule.htm

86rx7

Also i dont buy into this beaing a problem only on forced induction motors,.. it should show up regardless as its a seal support issue,.. not a seal expansion issue.

cortc

rotarygod: You are very wrong, I have not seen one but I have seen a few RX8 rotary housings (5 as of last count, all with 10k+ and two with 25k+ miles...) and I did not have to see the one at sevenstock to know there is no problem with it...

rotarygod

Whatever, you win.

zoom44

this photo from ajax while blurry and over exposed actually does show the area we are talking about rather well. you can see the notch in the upper left of the port which is leaving the seal unsupported for a moment plus the extra shiny spot is the nick that was caused by the impact of the side seal. i cropped it so it will fit.

rotarygod

Let's just go along with cortc's statement that there is no issue with the side seals. This would mean that there is an issue with something else in this part of the engine. That leaves us with either the ends of the apex seals (doubtful) or with the corner seals. Mazdatrix has stated that the Renesis corner seals will absolutely eat up a 13B side housing. If it were a corner seal though, it would have done damage everywhere else.

The damage that was done to the Racing Beat housing may actually be small enough that it can be lapped off. They don't know yet since they haven't tried.

cortc brings up some good info never the less. If he has seen about 7 or so Renesis engines taken apart and none of them had any side seal impact damage, that supports the theory that this is not an issue with everyone's stock engines. Remember that Racing Beat said that the problems from side seal impacts they saw were from engines using forced induction. I still don't know why it would matter. I am curious as to the engines cortc has seen. Who do you work for that you have seen these taken apart? If these engines only had 10K to 25K miles on them and were still good, why were they disassembled so you could see the insides?

BTW: When you said, " I did not have to see the one at sevenstock to know there is no problem with it..." you stuck your foot in your mouth. There was a problem with it. We even have pictures! Racing Beat themselves admitted there was a problem with it and that's the second motor they've seen like that. Everyone there saw it. Who does that make wrong?

86rx7

Not to mention were not talking about rotor housings,...

Icemastr

THe only reasons I could see for you seeing the insides of 5 different engines would be if you worked as a mechanic for mazda, which if you are seeing that many would mean that there is some reliability issue, or you work for a performance R&D place or race engine shop and would have seen some of the issues we are taking about, so where exactly have you seen 5 renesis engines opened up?

Japan8

I thought that the dealers were just pulling and shipping the engines untouched to Japan and replacing them when any major issue occurs (that would requires cracking them open).... or is that just rumor?

RX8-TX

Most likely, FI makes it appear prematurely. You are generating additional heat and applying extra stress on the engine. Maybe all engines become nicked after a few thousand miles, but the effects are not noticeable. I wish I had done a compression test when I drove off the dealer, and one now with almost 20K stock miles.

Like I said, FI may only make it appear or be apparent prematurely.

rotarygod

FWIW the Racing Beat engine did not die from a broken side seal. It broke an apex seal under boost.

GeorgeH

iTrader: (2)

This has been bothering me for some time now - how do we know that the damage that was witnessed at seven stock was not a by-product of the failure? Isn't it possible that the side seal damage occurred after something else failed? Or is there evidence suggesting that the side seal damage was the cause, not the effect of the blown engines?


Oops, just read RG's post. Obviously, we do know that the failure wasn't caused by the side seals. So, this suggests to me that we really don't know for sure if there is a side seal problem, even under boost. Or am I missing something?

Rob Tomlin

Well, that makes us all feel much better now!

RX8-TX

Of side and apex seals: :p :D whats the word for us? Hypochondriacs?
I wonder how often do all of us get sick... :D :D

zoom44

one point i would like to make is i never heard anyone at racing beat say "we have not seen this on NA engines". i wonder if they have actually looked at any NA engines for this. they may have only opened the FI engines because they broke and they wanted to know why. maybe they just havent cracked open the NA ones yet. i might email jim langer and and ask him.

shelleys_man_06

I'm curious as how companies like GReddy, SFR, and SSR have managed to get their turbo kits out without regarding this situation. I wonder if they know about this shortcoming.

In the coming days, or weeks, depending on my school schedule (I'm behind), I'm planning on coming up with a probable analytical solution.

zoom44

well there already is a solution- pop open the motor and fill in that notch to better support the side seal.

shelleys_man_06

Damn. The gears in my head were already turning.

Mazda should've done this in the first place.

Well, since the RENESIS is still under experimental phase, as all engines are, of course there are going to be problems associated with creating more power. Luckily, Mr. P&P was nice enough to reveal what is going on. This thread has been a learning experience for myself, who has been into rotary engines since I was 16.

How does one fill in the notch to better support the side seal? What is the best material for this operation?

86rx7

You wouldnt be able to fill it in reliably, the better option is to contour and polish that area.

Once again, this will not cause an engine falure only a loss of compression which will result in slightly less power. I still dont buy into the FI having anything to do with this.


It would be interesting if someone with say 30k+ miles got a compression check done, and then someone with less then 2k miles (as few as possible) had one done either both on a mazda compressiion checker, or both with the same piston compression checker. That would put this to rest.

zoom44

right contouring and polishing the area would help reduce and hopefully eliminate the impact and damage to the side seals. i would think there is some way to fill the little notch to add support. since its an intake port and not exhaust there might be some material that you could use that wouldnt have a problem with the relatively low heat in that are and would stay put.

shelleys_man_06

Ah. Machining the notch will get things back in order, sort of. I thought of the compression drop while driving to school. Is it enough to cause significant power loss? My guess is since it's on the order of the one-thousandths, it may not affect the engine as much as we say it could. I may be wrong. As for the broken apex seal, that was expected to happen. You can't get everything right the first time. 86rx7, didn't you mention the apex seals were harder than previous ones in the RENESIS?

rotarygod

One of the guys there did say it when I was chatting with him. I forgot who it was. It wasn't Jim Langer, Jim Mederer, or the porting guy (forgot his name), so I'm not sure how reliable it was. I'm only going by what a Racing Beat employee said. This same employee also said they had played around a little with porting the Renesis but again no one else mentioned it. Who knows what the truth really is. Charlie, find out from Jim Langer. He's a smart guy. He'll know.

The Renesis apex seals are stronger (supposedly) than the older seals. They are also shorter in height.

I am with 86 on the fact that it shouldn't make a difference whether or not the engine is under boost when it comes to side seal issues. I don't see why it would be or how it could be. Again this is just what came out of the mouth of a RB employee.

cortc

Ok, well looks like some will see what they want and others will raise questions where none exist; part of the human condition I guess...

Not all engines that fail go back to Japan, only a few and just in the early build cycle. This is a mass produced engine and so far the failure rate has been well within the expected numbers. All of the manufactures including Porsche take back a few of the early problem engines it's actually part of the confirmation process... The Renesis is a very reliable engine compared to other high performance engines...

Rest assured what you have seen here is an isolated issue…

Gentlemen enjoy your search, will be un-subscribing to this one...

rotarygod

So you aren't going to tell us who you work for and how you have happened to see several Renesis engines?