Renesis side seal discussion
#27
David,
Thanks for some real world hard driving numbers. Also, great job in Ohio on your ST win!
P.S. Do you use dino or synthetic oil?
Thanks for some real world hard driving numbers. Also, great job in Ohio on your ST win!
P.S. Do you use dino or synthetic oil?
Last edited by JoeRX8ter; 09-05-2004 at 04:47 PM.
#29
Race Steward
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Do you think they might sue those responsible for spreading rumors? ![EEK!](https://www.rx8club.com/images/smilies/eek.gif)
So before I comment any further, or anyone else for that matter... I'll get a compression test done. My car has done ~35,000 km which is >21,500 miles. Still going strong as far as I am concerned.
I think we should wait and see the results of a diverse set of results before we judge. Don't forget CZ had bearing failures - did that mean they are all duds? No.
Cheers,
Hymee.
![EEK!](https://www.rx8club.com/images/smilies/eek.gif)
So before I comment any further, or anyone else for that matter... I'll get a compression test done. My car has done ~35,000 km which is >21,500 miles. Still going strong as far as I am concerned.
I think we should wait and see the results of a diverse set of results before we judge. Don't forget CZ had bearing failures - did that mean they are all duds? No.
Cheers,
Hymee.
#30
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Bingo Hymee... you hit on exactly what I was thinking on both points... what %-age of engines are seeing this problem of premature failure of the side and corner seals and unless you have some solid evidence, Mazda will NOT be happy to hear this... think about the beginning of all this conversations and draw your own conclusions.
#31
So ahhh...the renesis has a problem with the seals, and it just so happens that our annonymous visitor has the fix for it, for the right amount of money I'm guessing?
I'm going to take this one with a grain of salt, until I hear of other owners complaining of low compression at 15,000+ miles. If it's for real, how in the world would Mazda miss something so obvious?
I'm going to take this one with a grain of salt, until I hear of other owners complaining of low compression at 15,000+ miles. If it's for real, how in the world would Mazda miss something so obvious?
#32
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Originally Posted by BaronVonBigmeat
I'm going to take this one with a grain of salt, until I hear of other owners complaining of low compression at 15,000+ miles. If it's for real, how in the world would Mazda miss something so obvious?
besides, whats a 10%loss if it's torbo'd or super'd. Car is still gonna perfom great.
#34
Registered
My question is how does the opening point of the pirts have anything to do with the side seals crashing into the closing edge. The closing timing is the same as the old 6 port engines and those didn't have this problem. The only concern about the opening side being over too far is with the corner seals falling into the ports. That's it. This is where the Renesis ports are larger. They open earlier. They don't close later. Oh the large streetported 13B 4 port engines, this problem would occur. This was because the open area of the port was so great that more of the side seals were unsupported than supported as they passed over this point. However, the 6 port engines have the small bridge of housing between the secondary and auxillary ports that can hold up the side seals adequately. If this were removed like many foolish 2nd generation RX-7 people do, then side seals could be an issue.
I am not going to claim it is impossible since someone has found this to be the case on their engine but I am not going to just panic based off of one experience and say that all of the 6 port RX-8 engines are doomed. I'd really like to see the pictures to study them. I know it is an easy mod (assuming your engine is apart) to help fix this issue. Why isn't this an issue on the old 6 port engines? It has to do with the closing timing not the opening timing and these are the same as the old engines. I don't get it.
All engines will lose a little power over their life. Race engines see it faster because most of their life is at a higher rpm under much harsher loads. 3-4% for every 25-30 hours of race time is more like several years of street time. Don't worry about it.
I am not going to claim it is impossible since someone has found this to be the case on their engine but I am not going to just panic based off of one experience and say that all of the 6 port RX-8 engines are doomed. I'd really like to see the pictures to study them. I know it is an easy mod (assuming your engine is apart) to help fix this issue. Why isn't this an issue on the old 6 port engines? It has to do with the closing timing not the opening timing and these are the same as the old engines. I don't get it.
All engines will lose a little power over their life. Race engines see it faster because most of their life is at a higher rpm under much harsher loads. 3-4% for every 25-30 hours of race time is more like several years of street time. Don't worry about it.
#35
New Member
I think it is when the oil pressure gauge comes in handy.
OK I have seen this in the RX-7 mag talking about overhalling.
RX-7 needs a overhall when,
Idling getting gradually rough.
Harder to start car.
Losing oil pressure.
Excessive oil usage/consumption.
Losing turbo boost.
Poor fuel ecomony.
~ this makes so much sense. ~ although most are common sense![Wink](https://www.rx8club.com/images/smilies/wink.gif)
BTW I think checking the compression via WDS is a good idea
OK I have seen this in the RX-7 mag talking about overhalling.
RX-7 needs a overhall when,
Idling getting gradually rough.
Harder to start car.
Losing oil pressure.
Excessive oil usage/consumption.
Losing turbo boost.
Poor fuel ecomony.
~ this makes so much sense. ~ although most are common sense
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
BTW I think checking the compression via WDS is a good idea
#36
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Originally Posted by takahashi
I think it is when the oil pressure gauge comes in handy.
OK I have seen this in the RX-7 mag talking about overhalling.
RX-7 needs a overhall when,
Idling getting gradually rough.
Harder to start car.
Losing oil pressure.
Excessive oil usage/consumption.
Losing turbo boost.
Poor fuel ecomony.
~ this makes so much sense. ~ although most are common sense![Wink](https://www.rx8club.com/images/smilies/wink.gif)
OK I have seen this in the RX-7 mag talking about overhalling.
RX-7 needs a overhall when,
Idling getting gradually rough.
Harder to start car.
Losing oil pressure.
Excessive oil usage/consumption.
Losing turbo boost.
Poor fuel ecomony.
~ this makes so much sense. ~ although most are common sense
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
BTW I think checking the compression via WDS is a good idea
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
![Confused](https://www.rx8club.com/images/smilies/confused.gif)
#37
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Originally Posted by Ajax
So you're saying that by porting the engine (or at least polishing it), it's possible to actually get more power and make the side seals last longer?
If that's the case, and mazda knows about it, shouldn't they be doing a mass recall on the car and replacing every single engine?
If that's the case, and mazda knows about it, shouldn't they be doing a mass recall on the car and replacing every single engine?
Porting a renesis engine and tapering or folding over the closing edge of the ports to a smooth and not so sharp edge will in return give reliability and durability to the engine. I have seen Mazda tried to address the closing edge of the ports by making the port timing a bit later by the closing edge of the intake port but the sideseals are still getting shorter and shorter as the engine is putting on miles and miles.
I'm sure Mazda will figure out a way to protect sideseals and corner seals from premature wear but for now porting and polishing in a proper way will take care of this problem. I'll address porting and polishing and horsepower as I go along.
Last edited by Mr. Port & Polish; 09-05-2004 at 08:23 PM.
#38
Registered
Originally Posted by Mr. Port & Polish
Kind of shocking to find sideseal and corner seal wear so premature.
#39
Registered
Originally Posted by Mr. Port & Polish
I'm going to pick and choose my answers a little at a time. I'm trying to bring proper and positive info from my personal experiences. I do not live behind a fu#@%$%# computer all day to make you happy if I don't reply right away. I'm a shop owner and also a family man. I will not tolerate this type of bullshit or I will just keep my findings to my ******* self. I had enough for a lifetime last time I was here..
#40
Registered
Originally Posted by Mr. Port & Polish
Kind of shocking to find sideseal and corner seal wear so premature. I also hoped that Mazda would pick up on this problem from testing for durability. This problem effects many high performance engine builders when they are porting an engine larger then stock form. The renesis engine has an intake port opening larger then my streetport template that I currently sell for FD turbo engines and that template is not a mild port.
Porting a renesis engine and tapering or folding over the closing edge of the ports to a smooth and not so sharp edge will in return give reliability and durability to the engine. I have seen Mazda tried to address the closing edge of the ports by making the port timing a bit later by the closing edge of the intake port but the sideseals are still getting shorter and shorter as the engine is putting on miles and miles.
I'm sure Mazda will figure out a way to protect sideseals and corner seals from premature wear but for now porting and polishing in a proper way will take care of this problem. I'll address porting and polishing and horsepower as I go along.
Porting a renesis engine and tapering or folding over the closing edge of the ports to a smooth and not so sharp edge will in return give reliability and durability to the engine. I have seen Mazda tried to address the closing edge of the ports by making the port timing a bit later by the closing edge of the intake port but the sideseals are still getting shorter and shorter as the engine is putting on miles and miles.
I'm sure Mazda will figure out a way to protect sideseals and corner seals from premature wear but for now porting and polishing in a proper way will take care of this problem. I'll address porting and polishing and horsepower as I go along.
#41
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Originally Posted by Rotarian_SC
Thank you, I hoped you would do this.
Is the seal wear only based on total mileage on the engine or is it dependant upon how hard you run your engine?
Also I have heard that mazda is still putting its rotary engines through breakin procedure before they are put in the car. That would be one reason why it says there is really no breakin period needed in the owners manual. Do you think the simple break-in procedure could have caused a different seal position, and therefore when the car was being sold its horsepower had actually dropped from 247 to less than 238? Could there be some extra wear during the break-in procedure that would cause a seal gap in the car before it was sold, or do you just think it was completely emissions related?
Is the seal wear only based on total mileage on the engine or is it dependant upon how hard you run your engine?
Also I have heard that mazda is still putting its rotary engines through breakin procedure before they are put in the car. That would be one reason why it says there is really no breakin period needed in the owners manual. Do you think the simple break-in procedure could have caused a different seal position, and therefore when the car was being sold its horsepower had actually dropped from 247 to less than 238? Could there be some extra wear during the break-in procedure that would cause a seal gap in the car before it was sold, or do you just think it was completely emissions related?
#42
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I have taking pictures of my findings and I'll post pics with info so many members that are visual could understand exactly what is going on and pics of my ported engine with my "fix the problem mod"
#43
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Originally Posted by David Haskell
I have built 18 of these motors for racing in Grand-Am Cup. I have not seen any issues with the side or corner seals. We have run motors for 50+ hours in racing conditions with an average of 4% loss of power. This is about the same as a raced piston motor. I don't really have any mechanical issues with the motors, and we run them in 3 hour races with an average rpm of around 7400.
#45
The Renesis was in development for years. I'm sure Mazda tested numerous engines, running them for the equivalent of 100,000 miles or more before releasing the final production RX-8. While there very well may be a problem with some of the engines, it's hard to imagine that it's a general problem with all of them.
I hope Mr. P&P continues his research and continues to offer his insight and suggestions to the forum. I also think we should wait for more info before we all go jumping off bridges.
I hope Mr. P&P continues his research and continues to offer his insight and suggestions to the forum. I also think we should wait for more info before we all go jumping off bridges.
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#46
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This thread will NOT turn into a disgusting display like the last one, so here's the bottom line, either you post information in a respectful manner, or keep your mouth shut. Mugatu and Mazda Maniac, one more time trying to start **** and you're gone. I deleted a ton of posts, sorry if I deleted a good one ... but I was just trying to reset the thread back to a point where it was still just information sharing.
While I may not entirely agree with the thread starter, he's only posting his experience. There are people on here with a lot more RENESIS experience than the thread starter, and they have not reported any similar issues. Also, the RENESIS has been used in Star Mazda races all year, and the engine is rock solid in that series.
So while I don't think one persons experience proves that Mazda has a problem, he does have a right to post here. So if you just want to talk ****, go over to nopistons ... they'll welcome you with open arms.
While I may not entirely agree with the thread starter, he's only posting his experience. There are people on here with a lot more RENESIS experience than the thread starter, and they have not reported any similar issues. Also, the RENESIS has been used in Star Mazda races all year, and the engine is rock solid in that series.
So while I don't think one persons experience proves that Mazda has a problem, he does have a right to post here. So if you just want to talk ****, go over to nopistons ... they'll welcome you with open arms.
#50
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From what I got from the thread the seals will gradually wear over time and will need to be replaced in the future. That's almost normal from what I know about the rotary engine, it just means we need to know when to have these tolerances checked. The problem was exaggerated when you ported and polished the engine but the performance gains are substantial. Great, at least we have that knowledge in case we decide to try this option and we can buy a multitude of seals to keep the engine running strong. Thanks for your contribution Mr. P&P and fell free to P/M me if you make any more big gains, even if you don't have a dyno sheet at hand. Your work may bring problems, but for every problem there is a solution.