I have seen 2 or 3. One engine was in my other first gen that I ran 19 psi with a Greddy T88 on pump gas. The EGT's got up to 1800F and the compression springs collapsed. When I took it a part the rotor bearing was fine but the tips of the rotor in the front made tip contact with the irons and also the faces of the rotor kissed the rotor housing.

Alright. Now I will stop typing. I quit!

i have side and compression face clearanced rotors in my "street" car...

but seriously guys, chill. everybody has their ways of building engines and their little "secrets." just let it go. let charlie's build thread be his build thread, not a bicker fest. i have alot of respect for both of you (phil and glen), but if you go back and read through this entire thread you will probably say wow.

goodluck with the engine charlie, cant wait to see it done. ill probably have you some numbers about the time you get your car done. lol

Thanks Masin,

I dont care about the bickering though, to me its informative and I hope others can get some good info from this thread. :)

I want to make a minimal 375 whp on my setup, 400 would be nice. Just be a quick little NA car ;).

Phil, in the begining I tried to get the point across that we are increasing the clearence that mazda already designed for stock outout...

I am far from arrogant becuase I did not want to go into a large discussion on how we do it ...I also did not want to post some elses explanation once you did it for me I felt it would not hurt to elaborate.

I have a track record that proves what I do works and I am going to live by that becuase it is tested. I do understand your point and i wish I would have handled it different , I kinda stay back usually due to the fact that this is one of the things I am not good at (discussing our techniques with out giving to much away).

I have had some really bad expirences when it comes to trying to discuss what we do. I have spent countless hours testing and studing rotary engines. I feel like I have earned my knowlage and it is very important to me.

Now to get to the issue at had, I would think if it is even a remote possiblity of having issues with clearence any builder would take precuasions to make sure it was no longer a risk even if it is a small risk. I would be arrongant if I said well i dont think it will happen therefore its not going to. Like for instance the rotors going from side to side under load, if it is even the slitest of possiblities would it not be a disservice to your customer not to atleast regonize that its possible and try and account for it????

My point is this, even the slitest chance of the rotors needing clearcence would it not be better to have the clearnce?? When you look at the over all cost of an engine the cost of clearncing is negligable. I am not arrogant in fact the only reason I am on here is to help the communitee infact that is why we do what we do. Tom and I as the owners of AZRR started this becuase we are selves could not find a builder that would fit our needs we both are rotor heads first

Glen, That's funny you said that... because this was your first respond when i wanted to clear up what you meant by clearancing rotors.


I am not going to disagree with you about how you should of handled it from beginning.. but you continue to tell me to look back and read but I still don't see you answering my questions until I posted bit more details to what you might be doing.
Even in the most recent post..

here is a question for you.. So, how many engines you broke down that was street driven and failure was due to clearancing??

I'm in a field where stats matter.. so, lets see the stats.

The thing is that, in order to be scientific and state that you have experience and so called 'track record' to prove it only makes me want to ask you more question. Why? because realistically I know in order to find out longevity and endurance of the engine it would take someone to put real world miles. Unless you been building engines since you were a kid and scientifically documented, I can't quite believe what you say. I mean its like when I had a chance to ask Ianetti about his seals.. I was surprised he said not to buy his seals for street use. And I know he's a scientist and I believe what he said to me.. which was, in the real world the engine experience far more variable than on the track.. And he pointed out to me that Mazda spent their time experimenting and came up with the seals..

Glen, I understand that this thread has turned into back and forth bickering. Maybe you misunderstood what I was asking and maybe I misunderstood what you are stating.. Who knows.. I know you keep mentioning about your secrets... Sure, I respect that, but maybe as a vendor/professional maybe you need understand that explanation vs. hard number is completely different. You don't need to be so defensive when what you might be doing is something that's already been done but spec might be slightly different. Who knows.. Hope you understand this time what I'm getting at.

Would you expect coke to give Pepsi it recipe? Come its the same basic thing it soda why would they not want there specifics to be know by everyone??


Oh and Phill "track record" means I do have stats that prove what we do works out of over 100 engines I have two fail, and those were arguable not my issues.

Phil make point man you have so far just teaken shots at me, this gets ingonore by me so give me something to understand please

LOL! I guess it continues on..

I don't know where in the world you still think I'm asking you for your specs... I've repeated over and over and I don't want to know your stinking specifics of your "recipe". LOL! Seriously, I don't care!!!

Second, I didn't ask how many engine you build failed. BUT I asked how many engine you broke down, that was street driven, that needed a rebuilt because of the clearance issue. I'm assuming you get your customer's engines and then you break it down and inspect??? So, I'm asking you how many of those were failure due to clearance issues!! Because if HUGE number of engines are failed due to that specific issues than I will admit that my statement about clearance is NOT Necessary is wrong.. But so far, that's not the case by numbers given by my builder and BNR...

And yes, I'm sure you and 99% of the builders out there will say the same thing that its not your fault that the engine failed.. So, no need to state that..

LMAO! I can't even understand what you just said above.. make what point?? and only shots I might of made is based on your statements that were somewhat false and misleading. And I have no clue what, "ingonore" is...

But my argument at this point is, is clearancing the rotor for street driven engine necessary?? As you disagreed that when I stated that its 'NOT necessary'. And the point I'm trying to make (if you want me to make some sort of point at this point) is that its not as there are thousands of engines that has stock clearance (NOT AZRR's special proprietary clearancing but with Mazda spec) and have lasted. Just trying to make the point that its not necessary and that statistic of number of engines you have broken down with this issue will resolve the point at hand...

So, did I make my point?? Hope that's clear to you.

Phil Chucky is right lets take this to pm or leave it be...Do what you do and I will do what I do

If you wish Glen, but I'm just trying to clarify why clearancing the rotor for street engine is not necessary as you disagreed in the past.. Just wanted to know how many you've seen with this specific failure. But, we'll take it to PM if you wish.

I really cant tell you a number....honesty Phil it been a long time, i have been tearing engines down for a really long time I would say 20 out of 100 had contact after going big single. The issue is that the rotors being clearence may not have been the issue there were so many issues, broken apex seal, carbon lock, detonation etc.

Now this is why it comes to a professional opinion, you may get away with it you may not...I dont want to risked it. If their was a big risk in having more clearence i would worry but there is not. So the risk out ways not doing, but again this is my professional opinion. Phil your guy may never have had an issue so in his professional opinion he say its not worth it. I was not saying anything about his skills I dont know the guy but I do know I believe in it.

I built an engine with no clearence (stock rotors) it blew up two reasons one the rotors hit the side plates and it had looked liek the shaft deformed., Rebuilt it not changing anything but clearnce the rotors and it is still make power today that was years ago.

OK, So really long time as in 25+ years?? J/K..

So you still didn't quite answered my question.. close.. but not quite. My question was, how many street driven as in NOT HIGH HP motor or high REV motor that failed due to side clearancing of the rotor. By the way, I never disagreed that clearancing the rotor for HIGH HP or HIGH Rev motors :)

Well, i've decided to use my contacts and call/email several other builders in the country to get some information about this..

One builder in LA (Louisiana) stated to me that he has not seen any engine he took apart that was failure due to clearancing the rotor. He also stated that its not necessary for street engine thats not high HP or high Rev.

Another builder in NE stated to me, "the only time i have seen failures of that nature (rotor hitting side housing) is from a spun bearing due to lack of oil.
for the builds you describe (less than 400rwhp and 8k rpm) we do not clearance the rotors as you describe."
**Description I gave is the RB quote regarding clearancing rotors**

Next builder I've contact is someone most of us here knows...
He stated this..

I'm waiting few other builder responses to this topic.

Ok =, Phil you have demestrated that you have something against me ...

Everythign i say gets ripped up ...It been a long time or me 10+ years...Sorry if i was not spesific on such an important part of my statement

So I am done with it....

Hey Chucky ...porting is comign soon this should be fun...Please dont post anymore of the picture here

Glen,

Dont sweat it buddy. Keep up the good work on the engines. I have seen a few of the ARR vids and the cars run well...

Bryan@BNR

LOL! No I just wanted to make a point and to your disagreement regarding clearancing is 'not necessary', which means NOT required, or essential on street application motors. I asked you multiple times to tell me how many engines you've broke down that were street driven engine (low HP, below 8000RPM) failed because of so called oem clearance of the rotor and you dodged the questions. Just as you been trying to make your point why, I been trying to make a point that its not.. Just trying to reason with you... maybe its my pitbull mentality?? who knows..

Bottomline, people could make their decision based on facts. Which I've taken time to ask builders who have seen many many engine internals with issues. If say 5 builders with total of 1000+ engines they torned down and sees less than 5 that failed on street engine because of clearance issue (less than 1%), than its NOT Necessary for street driven car.... Point in which you disagreed and wanted to make my point with bit of research and numbers... And not just telling you I came up with it using my "proprietary" method of determining its not necessary.. :)

Again, No hard feelings... seriously!

I agree with Bryan, Don't sweat it. I'll admit that you do do good work on the engines. Not discrediting you on that... as I stated before, if I would need balancing and 'clearancing' the rotors, I would consider you.. Unless you are mad at me and if I send you my rotating assembly you'll fuck it up on purpose;)

But, Regarding disagreement at topic, I like to make sure my point is made during the debate... Ulitmately, people will decide based on points both of us made :)

I just got off the phone with one of DGRR supporting vendor and a rotary specialist with 30 years of experience, Brian from Rotorsports Racing.

When I asked Brian about this specific kind of failure (side rotor clearance), he said he has seen ZERO on a street driven car. Not only that, he has seen very very few from race engines he has built over the years.

Got off the phone with yet Another builder... a well known 3 rotor shop in OH also confirmed with me regarding clearancing the rotor.

They also have NOT seen any motors they torn down that's street engine (less 400HP/less 8500RPM) that failed because of side rotor/side housing clearancing.

call BDC and ask his advice....LOL....LOL....


Ok, we have to remove Phil's aviator pic as its becoming him.............

See ya Friday! And if you get a chance to see Brian (BNR) he has going to have you bring me a TII diff if you have room...

LOL!

I know.. Maybe I am what BDC mentioned:) Dang.. My apologies!

I'll tell Stephen as he's heading to BNR to take the wheels off... then bringing it back to me.. So, maybe he could bring the diff also.


I've also talked to another builder in FL and he just stated to me that he also never seen street or built motor that had issues with side of rotor to iron clearance issue...

Yes, I know... Its getting old... But to be a valid, high number of sampling is needed...

Time for me to jump in lol...

For street no more than 8k RPM Clearancing the side of the rotors is not necessary.. unless the costumer wish to have it done.. for future hp needs..... Simple... :)...

Jump!

perhaps I'm missing it in the deleted posts on the other thread, but I thought that Charlie said he intends to use his motor/car for high RPM (9K) and track use....meaning that the clearancing was necessary?


As a point of personal education, what is the possible downside to clearancing rotors for a street car? Possible side seal wear?

I think possibility of increased blow-by, which ultimately will lead to shorter engine life?


-Ted

I'm curious, how would blow-by lead to shorter engine life? I understand how it could reduce power, but it would seem to me that greater clearance on sealing surfaces reduces seal wear and would increase engine life in exchange for maybe less fuel economy.

Didn't Mazda increase side seal clearance drastically on the Renesis? They must have done that for a reason, right? I personally would trust Mazda engineers to have better data than the entire engine builder aftermarket put together.

That is correct. I also plan on driving the car on the street every chance I get. I got the clearancing done for extra insurance when I will be running the car in the higher rev's. To me its worth it.

Blow by would not increase the side seals still do there job. Have Phil call all of his engine builders to find out

Joff,
If mazdas engineers were puerto rican, we would have some of the badest production cars ever :D.

Just got off the phone with Paul @ Mazmart (home of Rick Engman). Paul asked Rick about this for me and Rick says he does not clearance the rotors... Not even on his race engines.

LOL!

So, What happened?? I thought you said you are done with this??

Hmm.. I guess you were lying to me:)

Anyhow, Another thing you guys can do is listen to Glen like flies on shit :)

Just saw this thread show on top.

I have been building these things since 72 and have never seen this as a failure point, street or race. The IT motors spent their lives near 8 and the GT motors at 10K.

Resulting damage from bad bearings and or bad build or gear walking, yes, many.

Here are my 2CS.

I do not see the necessity or any cost benefit. Mazda does not include it as one of their build hints, and it is not in my copy of the Mazda RX7 Competition Preparation and Service Manual. I do not have the latest versions though so I will stand corrected if that modification is recommended. (remember I am the factory freak) I do not know of any of the top builders that do.

But I will not dismiss it completely either. Who knows what the future and innovative experimentation may result in. I will leave this one to those with deep pockets. I’m having enough to do with flat bottoming the open road car and working on this buggy.

When a rotary is built properly to spec with new parts or parts that meet spec it will perform and be reliable. It is then to the client to take care of it. A good build isn’t anything if the oil isn’t changed or it is run out of water. (but the light wasn’t on that long, just until it stopped.) They may come in the shop that way, but they leave knowing the proper care and feeding of their investment.

Side seal clearance was not increased drastically. There is no difference between SS and CS. The clearance of SS in the rotor is different because of the design of the new SS.
Rotor to side housing clearances are less .12-.21mm for FD, .05-.19mm for Renesis.

If you are inducing any blow by it will shorten the life of the motor. First by contaminating the oil and building up combustion gases in the oil containment system. Beside loss of power.

Amen!

Thank you for your input Rx4ur7!

That's interesting.. I was looking for that information about FD vs Renesis clearance.. Thanks for posting that.

Same thing was also told by another very experienced builder.

Over the weekend I met up with the guys from SpeedSource and asked them if they clearanced the rotors on their 20Bs.. They said, "yeah we do. But VERY little". I ask how little and they said they barely clearance it..

Also they told me their peak HP is at around 8500RPM.

Just thought I post what I found out :)

Interesting thread... I'm no engine builder but I've heard at least a couple of piston guys mention using increased piston-to-cylinder-wall clearances to avoid contact due to the piston expanding when it sees a lot of heat (high boost). Due to the shape of the piston inside the cylinder I don't think those guys would be need to be very concerned with flex or eccentric shaft wobbling... I would venture it's just expansion from heat.

I suspect there are some similarities and some differences between how the piston engines and a rotary engine will react to the additional heat (not a lot of forged aluminum rotors out there), but something along those lines may account for why some builders are suggesting that increased clearances and others don't. I suspect it may be more important in engines that are seeing a lot of heat. This may explain why one builder observed a higher percentage of FD failures than FCs... it's pretty much a given that the FD runs hotter.

All this arguing gave Max a headache.

I guess I take it for granted but in the NE most of the rotary guys help each other. We share a lot of info and this will only help all of us in the long run.

I take .003 off each face. Some take more off some take less, most I know go with .002. I've run 550-600hp for years with nothing touching. As soon as I started trying to go over 630hp or so, things started flexing and the tips touched and I had the rotors clearanced.

Earlier this year at a drag racing event I spoke with Ray@PFS and asked him one of those top secret questions, not only did he answer me honestly but even offered to send me the part I needed to get it going. In the end we all need to help each other.

Anthony

I agreed 100%.:icon_tup: Great post I hope we as a community can help each other like this.