SuPerHerO::tOnY

okay..how about back to the point of this thread abuot how and why and if its true about this reliaiblity issue

brillo

Just outta curiosity, could synthetic fluid help this problem? would that reduce the wear?

thew

not likely... Oil is oil. and this issue sound like normal wear to me. IE. Rings on a piston...

just my 2 cents.

rotarygod

To get this thread back on track, I'll post what I know about side seal issues. I actually already stated them a couple of pages back.

As the rotors turn there comes a point where the side seals are riding along parallel to the ports. On really big ports this can leave alot of area that the seals are not supported on. This includes the front edge. On some really large ports the loss of so much side seal support can cause the front edge of the side seal to just slightly move down nto the port opening. It isn't much since the back half of the side seal is still supported by the housing. You really need to stare at a disassembled engine to fully understand this. As the rotor moves towards the closing edge of the port, the small amount of side seal edge that is hanging down may get caught by the sharp edge of the closing side of the port. This doesn't usually just wear the seal down but rather just usually breaks them. This sharp edge is very common porting practice by alot of people. Here's the cure.

When people port this large, rather than leaving a sharp edge here, they need to gently taper it from the port into the engine. You want this rounded off. It is better for flow and isn't a sharp edge any longer that the seal can get caught up on. It is a win win situation.

A large street ported 4 port engine admittedly doesn't have the late port closing timing of the auxillary ports of the 6 port engines. It is being mae to sound like this edge is so far up on these engines that this problem is going to occur. It didn't happen on the older 6 port rotaries and they had the same closing timing as the Renesis ports do now. The problem isn't that there is a ton of timing. The problem is there isn't enough support for the side seals. Fortunately the 6 port engines do have support! The small "bridge" that is between the secondary ports and the auxillary ports does support the moving side seal. The problem occurs on huge ported engines that have 3" long ports. With this bridge still in place we aren't losing 3" of support but rather closer to 1"- 2" in a couple of places. The total port area adds up but the total amount of side seal support stays greater.

The fact that the Renesis ports are 30% larger than the older 13B ports is irrelevant in this scenario. They only open sooner. The closing time is the same. It is the closing edge that would cause a problem not the opening.

As far as the side seal clearances goes, these engines are like this from the factory! They were not worn down to this level. Racing Beat has stated that they typicaly clearance side seals around .002"-.003". I agree with this number and so does the original thread starter. This was possible on the older rotaries. However, the Renesis seals are shorter from the factory. Racing Beat has found after searching through many different seals that the closest tolerance they could find of any untouched seals was .009"! The worst they tested had in the buch was .018"! The seal clearances that were found on the torn down Renesis seem right in line with what has been found in all Renesis engines from the factory. I'll agree that they should be much tighter than this but the fact that this engine had tolerances this high does not mean there is a problem. That is just how they are built now.

FWIW: Mazdatrix used 10.0:1 compression Renesis rotors in a 13B engine. They also noticed the very poor side seal tolerances. After much dyno testing they have yet to hit the same horsepower numbers as a 13B with '89-'91, 9.7:1 compression rotors! They have been lower! Yes the Renesis would make more power with tighter tolerances between the seals. It kind of makes you wonder if the high horsepower prototype engines has these tolerance issues or not.

My personal opinion is that when this engine was torn apart and all of the clearances measured, it was a misdiagnosis of the real issue which is quite simply that there isn't one. If one is not aware of the much greater clearances from the factory then it is very easy to start speculating what is happening. Give the guy a break. He does know his rotaries pretty good. One thing is for sure, we now know for certain that he ported it!

Gibbo

I want to make a comment that just because one person has found issues with his motor does not mean that everyone will have these same issues. I have read a lot of knee jerk reactions to one persons post. It may be true that he found these issues, however he may have got a lemon (it does happen).

Before everyone bags mazda for not doing this or not recalling that, wait a moment and ask yourself if you have noticed anything different with you car, you probably haven't. Had this thread never been posted you would never have questioned the motors reliability, because nothing is wrong with your engine.

Let's be sensible with responses, Mr. Port and Polish posted his findings with HIS motor. This is one motor not 100. Take the posts in the context that they deserve not as an official notice.

I have had no indications from my car that any of this is happening to my engine. It goes as well as the day I bought it.

rotarygod

It isn't happening to your engine. It came like that. They all do.

brillo

how do we explain his loss of power? is it from the porting? fluke of nature? damage from being driven hard? Just wondering............

Ajax

I did the exact same thing. I looked in the FSM.. I wonder if we can find a copy of that engine manual.

BOOSTD 7

I will call my contact at Mazda first thing tomorrow morning and pose some of these questions. I know the side seal is totally new on the RENESIS, and from seeing them in person they're set back farther and thicker than old ones.

Like said before, I'd bet this is normal, but I'll get some answers.

rotarygod

Typically rebuilding info if available would have clarance specs. The Renesis for whatever reason is supposed to use a certain side seal in a certain groove rather than just having them all be interchangable and clearanced by the builder. If you go to Mazdatrix's page of Renesis parts, you'll notice that there are several different letter designations for the side seals and the part numbers do reflect this. On the sides of the Renesis rotors there is a letter stamp. You use the same letter seal for that same letter groove only. This makes no sense to me. I don't see why one side seal couldn't go into any side seal groove. The new seals are a wedge shape as opposed to the older seals flat profile. They are also closer to the face of the rotor than the older ones. I don't know why this would affect the location that each one has to go into. Ryan, ask them why they have diffeent letters for different rotor faces.

B-Nez

What I'm wondering is if he ported just the auxiliary ports, or if he ported the secondaries, too...would have liked to have seen those photos.

Hymee

iTrader: (1)

Thanks for undeleting a lot of those deleted posts Ryan

My email notification still has the exact wordings of one of Mr P&P's now invisible posts :p

Cheers,
Hymee.

Mr. Port & Polish

[QUOTE=rotarygod]To get this thread back on track, I'll post what I know about side seal issues. I actually already stated them a couple of pages back.



The fact that the Renesis ports are 30% larger than the older 13B ports is irrelevant in this scenario. They only open sooner. The closing time is the same. It is the closing edge that would cause a problem not the opening.

As far as the side seal clearances goes, these engines are like this from the factory! They were not worn down to this level. Racing Beat has stated that they typicaly clearance side seals around .002"-.003". I agree with this number and so does the original thread starter. This was possible on the older rotaries. However, the Renesis seals are shorter from the factory. Racing Beat has found after searching through many different seals that the closest tolerance they could find of any untouched seals was .009"! The worst they tested had in the buch was .018"! The seal clearances that were found on the torn down Renesis seem right in line with what has been found in all Renesis engines from the factory. I'll agree that they should be much tighter than this but the fact that this engine had tolerances this high does not mean there is a problem. [QUOTE]





Ok for the sake of this thread I'll say this. I don't think you have actually seen a renesis apart in your own hands. The opening of the intake port is serioulsy large and the closing of the port is larger then any stock port mazda has ever built.

I have written at another rotary engine site detailed information with pics about huge streetports and a reliability mod for a large intake opening and large intake closing of the intake ports.
No way no how a sideseal to cornerseal gap should be .018 to .020 of an inch. Naturally aspirated engines need sealing compression for many reasons. A large gap only causes problems like: engine fuel flooding and loss of power. I was going to show proof of some cornerseal damage but have decided not to here. Because the sideseal has such a large gap it put so much strain on the cornerseals, that a groove like wear was present on the cornerseals(making the engine have a bigger sideseal to cornerseal gap). If your an engie builder you would know that is some serious wear for an engine with 14,000 miles. That wear is more typical on higher milage engines.
I repeat a problem of durability was aggreed on with a person that has more then 30 years of research and developement with rotary engines. I seriously hope my engine was an isolated incident.
My engine went fron 188 rwhp on 93 octane and 196.5 on 100 vp race fuel to 169rwhp on 93 octane. I took the engine apart and found nothing wrong but damaged cornerseals and a large sideseal gap.
Also it was confirmed that the cornerseal damage and larger sideseal gap was accelerated by the closing edge of the port.

I have done to the renesis engine what some builders only dream about and I've gotten more then respectable results. I tell some forum members to have some respect for that., AND THAT WAS THE INITIAL INTENTION OF MY THREAD...

smrx8

iTrader: (1)

what cost are we looking at if anyone wanted to port and polish a rx8 engine .i know you said your really busy i just wanted some numbers $$ also when you port the engine would in the computer sense somethings different and start acting different.

Mr. Port & Polish

I'll add one more finding with my engine. When I broke my first tranny I took it back to the dealer. My engine had a real bad hesitation from 1500 to 3000 rpm. I told the dealer to give my engine a compression check. It turned out to be 106psi 108psi and 105psi this is psi for every rotor chamber. Months later I feel lost of power and I decide to dyno the car. power was 169whp and I was unhappy. I drive the car back and do a compression test and the compression was 98psi 95psi and 98psi. Car ran fine just lost of power and fuel flooding problems were happening. Not the case when I had higher compression.

Again this thread is not meant to scare anybody. I drive my car insanely hard. This thread is to show the engine's potential.

Mr. Port & Polish

Sorry nothing personal but I refuse to port and polish other Rx8 engines. This is a personal journey and exploration. Plus I have work to seriously last me 2 years non stop.

Rotoman

Mr Port & Polish, Hi I know you said you are too busy to take on others, But will you be coming out with maybe templates and instructions that we can buy so we can bring to our rotary mechanics to have this work performed on our cars.

cortc

Ok, spoke to a few different individuals on this including one of my contacts at Mazda (We have many as we are a very large dealer group…) and our number one rotary tech at our Mazda dealership who has 15+ years experience with Mazda rotary engines, and has already worked on a few RX8 engines with 35K + miles, and there is absolutely nothing wrong with the Renesis and the seals...

This issue does not exist; it is actually funny how some of us have taken this even remotely seriously...

G8rboy

That's good to hear - thanks cortc. I can't believe how many people were putting for sale signs on the RX8's at the beginning of this thread. As long as it took Mazda to get the RX8 to the market, there's no way they would have missed something like this in long term testing. In fact, I'm sure they spending more time on this type of testing than say, making sure the AC was strong enough for summers in the US .

rotarygod

I am going to start by saying that I do respect the original poster of the thread. Please don't take anything I say as hostile since I am not intending anything as such. If offense is taken to anything here, this is my disclaimer that says otherwise. Now saying that...

Let's go compare specs between port timing between the Renesis and the earlier 6 port 13b's since I may or may not have stated the wrong info.

Here are the Renesis vs. 13B 6 port intake port timing specs.

Primary intake port opens at 3 degrees ATDC. The 13B ports open at 32 degrees ATDC. I am correct when I said that the Renesis opens much earlier.

Primary intake ports close at 65 degrees ABDC. The 13B ports close at 40 degrees ABDC. I did incorrectly state that the closing timings are the same and I have been corrected. I am correct though when I say this port is not big enough to cause the problems found in this thread. Let's move on to the other ports to see if they could be a problem.

Secondary ports open at 12 degrees ATDC. The 13B open at 32 degrees ATDC. Again I am correct in saying they open much earlier. Once again this also isn't the side of the port that has any impact (literally!) on the side seals.

Secondary ports close at 36 degrees ABDC. The 13B ports close at 30 degrees ABDC. Once again they aren't the same so I misquoted this figure. Once again this isn't big enough to affect the side seals. That leaves us with only 1 set of ports left and they are the relevant ones to this thread.

The auxillary ports open at 38 degrees ATDC. The 13B ports open at 45 degrees ATDC. Once again they open earlier as expected. No surprise here.

Pay attention to this part! The auxillary ports close at 80 degrees ABDC. On the 13B they also close at 80 degrees ABDC! I was right as far as the port timing openings on all 3 ports and the closing timing on the auxillary ports which are the relevant ones. So I messed up on the closing times of the other 2 small ports. Yay. They don't have any bearing on this thread though and don't have any issues with side seals. Now let's go back and again explain some things.

On large streetported (here's the key...) 4 PORT engines, the secondary ports can get so large that the side seals aren't adequately supported by enough side housing surface area and have the very slight tendancy to fall down and hit the closing edge of the port damaging them as stated. This can not happen on a 6 port engine in it's stock form. It doesn't matter if it is a Renesis or a 13B. The reason being is because the secondary and auxillary ports are seperated by a "bridge" that does support the side seals as they ride over it. If you were to port an engine and grind this down where it can not support the side seal, then it is possible for this to happen. If your engine is stock this is not a major concern.

I do not doubt that SOMETHING is wrong with the engine in this thread that has caused it to wear prematurely. I can without a shadow of a doubt say that it is not a widespread issue and that no one should be overly concerned with it. Anyone who has seen a 6 port engine taken apart can easily follow the path of the side seal to see how it stays supported between the 2 ports. The auxillary ports could close at 110 degrees and not have an issue (Well maybe the fact that there wouldn't be any more power to be had from this closing time!). In contrast the 4 port streetported engines could close at 70 degrees ABDC and have problems. They also don't have the support where the middle of their large single port would be.

Every Renesis engine has poor seal clearance from the factory. I don't doubt that this engine has had the problems that have been stated. I will not call anyone a liar and am not being disrespectful. I am just stating facts. I would actually like to see the pictures of the damage. Something has happened to THIS engine. Thousands of others have had no problems or loss of power. Race teams have had no issues. This is not a widespread problem and panic should not started based on a single limited experience. My attention would be focused on the springs.

cortc

rotarygod: Good post...

shelleys_man_06

So, this has moved from a seal issue to a spring issue? What can be done to properly port this motor, without running into the gross oversimplification Mr. Port & Polish made?

Ajax

Would aftermarket seals with better clearance yield better compression and therefore better performance and fuel economy?

Preacher

Interesting.

brillo

do we have any theory why the clearance tolerance is so much looser than before? Why would mazda do this? Is it a cost savings measure? I can't see this as being an expense issue, but maybe I'm wrong. I would also like to know if a tighter seal would improve gas mileage.

can someone also comment on how dino vs. synthetic oil could have a positive/negative effect on the seals on their function in a stock setup?