i agree with most of your post however, the tighter the seal clearance in the groove the less pressure pushing on the seal. the greater the seal gap the more pressure there is pushing on the seal which can cause the seal and housing to wear faster.

 

Here's some info that may be relevent to this thread.

http://www.rotaryeng.net/seals.html

 

I understand ur point and TY for ur correction! dam ur really making me think now ewww, when I posted that part I really didn’t think about it to much as I don’t think it is really that much of a factor (assuming that of coarse they clearanced then to stock spec if there were not any supplied spec’s with the ra seal’s) I was really after what size and clearance compared to oem, I should have been more clear, but now since u got the mice in my head running on overdrive in there little wheel lol, I have another idea and another possibilities I wonder what running clearance at temperature the ra seals have vs oem “”how much do they grow at temperature”” or does ra even know ARE THERE SUPPLIED CLERANCE SPEC’S WITH THE SEALS? (fyi not knowing the materials used in the seal this is a real long shot)Why I ask is if there is not supplied clearance spec’s 1)it’s the same as oem or 2)they don’t know! Possibility maybe at running temps in a tight clearanced motor (apex seal wise) when the seal gets hot it grows and then sticks in its slot causing the wear on the housings there 4 making more heat exctra! Example were I came up with this keith black piston’s (shuuu bad word lol) this is a copy and past from there web sight “KB pistons make more HP by reflecting heat energy back into the combustion process and, as a result, the top ring runs hotter and requires additional end clearance. Increasing ring end gap does not affect performance or oil control because normal end gaps are realized at operating temperatures. Failure to provide sufficient top ring end gap will cause a portion of the top ring land to break as the ring ends butt and lock tight in the cylinder. The broken piece may cause further piston or engine damage. Excessive spark advance, lean fuel mixture or too much compression for the fuel and cam used will make heat sufficient to butt piston rings with as much as .060" ring end gap. The entire top land can expand enough to contact the cylinder walls, when close to melt down temperatures are reached.” the material used in the piston makes the top ring run hotter closing the gap if the clearance is not set right, fyi they require more clearance that stock or other manufacture’s pistons do (more than any one last I checked), I wonder if something similar is going on with the material used with the ra seals! Personally I still lean toward the lack of lub thinking! This is just a Possibility (and or food 4 thought)!

 

I just pulled my motor about 13k miles (17psi +/- 1psi) with RA seals and premix...~1oz to gallon

my housings looked like these (not my picture...earlier in the thread)


I'm moving to Mazda seals and upping my premix.


apex seals springs looked pretty flat too.

 

Dub, you're still running the stock OMP? What ratio are you thinking of premixing at?

 

Upping the premix wont help the chatter, that'd be the springs failing to cope.

The housing wear doesnt really look too bad from my experience but if they were new housings 13k miles ago then that maybe exessive.

 

My housings looked like that when I took my motor apart
due to a spun bearing.....car ran flawless unytil that point
no starting issues/ compression was very good
6K miles

I will be using those same housings in my spare engine

 

I dont no about all you guys but i run a min. of 50-1 premix in my fuel.

 

You're using over 2 ounces of premix per gallon of fuel? Is this with or without a working OMP?

 

I am also using ~50:1 premix AND factory S4 mech OMP set w/ no slack and for maxed flow at WOT.

3mm RA seals.

Keeping the EGTs way down (700-800C at manifold).

I just put in a quart of premix w/ every fill up.

It has ~10,000 miles on it (daily driving, a season of Auto-X and a hillclimb), still feels like it is gaining compression.

Break in has been taking a long time (hillclimb really helped).

My rotor housings were pretty much junk housings, all spark plug holes cracked, been through 3 blown engines I know of, deep apex seal scars in the power stroke on one housing.


It was an experimentally ported motor.

This was the 1st build of it w/ 2mm Atkins seals
https://www.rx7club.com/rotary-car-performance-77/pics-blue-tiis-engine-build-new-type-primary-port-489429/

 

Yep, I have the OMP on there but i can say that it is working

 

Hey all. Well last month RX7 nut helped me put the motor together for my vert, we used RA seals from late 05 (new) and housings and bearings which are in really good condition. I have been running it VERY rich (550cc primaries on a N/A ECU) and about 2 ounces per gallon pre mix with the stock OMP. The motor has about 2k miles on it now and we'll be tuning it soon with somewhere between 8-12psi. I should check compression soon. I'll report back if anything exciting happens with this motor

 

No, since I have a E6X Haltech...I don't use the OMP.

I usually don't fill up the FD...another habbit I picked up from axr6.
I was using 8oz for ~8gallons...I guess I'm going to run 1.5oz per gallon (but seems like that wouldn't help the chatter).

the housings were lower milage...under 50k.

After I built the motor, RA came out and said "don't use springs in high boost" probably because of heat...not sure what high boost is??? where stock is 10psi...and I ran around 18psi, almost double maybe I killed the springs? who knows...I think my engine building "trys" are over. I'm tired of wrenching...so my goals with the car have changed.

currently I'm putting together a set-up that should work very well with off the shelf remans.

 

Thanks for the info....can you expound on this 8 gallon gas habit a bit?

As far as 'trying' to rebuild motors, just stick to OEM Mazda internals and everything will work fine.

 

if you know Albert...he is about keeping things as light as possible, haha!!

I don't do anything but joyride and autoX (and occassional track event) my FD...so why do I ever need a full tank? It could be weeks between rides...fresh gas every ride.


I hear you about everything working fine...but I'm done cleaning/clearancing/porting etc. I want 12mo/12k mile warranty from Mazda, a simple engine bay, safe tune, and a set-up that can swap short blocks by anyone with minimal tuning effort...if any.

 

I dunno man, remans are expensive as ****. I can't imagine you're having to spend *that much* time porting etc. Well, you're a smart guy, I'm sure you'll do what works best for your application

 

It's just as expensive to buy new housings and a rebuild kit.

~1200 for the housings
~1200 for the rebuild kit

reman ~2500 and will have more new parts(and 0 hours of my time building) and a warranty...I'm sure one day, I'll get the itch to build another motor. As I have a fully balanced rotaty assembly from Rick Engman sitting around Keeping it for a rainy day I guess

 

It sure can add up!

I was blowing motors so frequently I focused on used parts/re-usable parts and built a "poop motor".

I used Hylomar so all my gaskets have been through 4 motors, I used re-useable Mcmaster car Viton coolant O-rings and dowel O-rings, Junk rotor housings survived 3 blown motors (so it makes a bit less power under 3,000rpm big deal), a fist full of used sideseals incase I have to swap a rotor, cheap RA apex seals and used parts for every other seal.

Problem is, now that the set-up/tune is sorted out I just can't blow up the poop motor.

Basically, I am advocating not to bother building a nice $$ motor until you have sorted out that whole blowing up thing.

Luckily side plates usually survive the blowing up just fine and that is where 90% of the work is.

Shocking, but a well sorted rotary is very reliable even when heaped with "abuse".

 

what is the part # for the mcmaster car viton coolant o-rings and where can i buy them?

 

They are a standard industry O-ring with viton outer coating encapsulating a silicone inside . McMaster-Carr.com is the online store most people buy them on.

We have only found a size to work for the inner O-ring that takes all the abuse and we use a stock outer O-ring which can be re-used if removed carefully so it doesn't stretch and is cheap if it does stretch.

If you search coolant seals or McMaster-Carr on this site you will find info.

I will look at home for the receipts for the part #s.

 

thanks blue ][

 

fter reading this thread i'm trying to devide if i should try running atkins seals or ra seals with like 40:1 premix.

 

My experience with 1 set of 2mm Atkins seals and 1 set 3mm RA seals and 1 set 2mm RA seals is this.

The Atkins seals will wear themselves into sealing much faster and be very easy on the housings, BUT will break with even light detonation.

RA seals will take much longer to wear the HOUSINGS into sealing are very hard on housings BUT I have not been able to break a seal with detonation or otherwise.

Even the 2mm RA seals survived high RPM detonation so bad the car lost all power and vaporized the sparkplug ground strap as well as several audible detonation events at ~4,000rpm full throttle.

Atkins 2mm seals gave out on my 1st 5th gear pull after a long break in, didn't notice any detonation signs. The map had been used for a long time on previous 3mm Hurley seal motor- though it was lean in high midrange compared to what I run now.

If you are using good rotor housings I would recommend stock performance seals, if you are using brand new housings I would recommend stock or ceramics if you can afford it and if you are using junk rotorhousings use RA seals.


I took my 3mm RA seal motor apart after ~20,000miles as it ate an EGT probe and stuck a corners seal in the rotor. It did have high wear even with 50:1 premix and maxed OMP, but no chatter. There was full chrome left even though the deep gouges in the rotor housings were worn back out flat so I put it together with 2mm RA seals since the 3mm rotors were junked.

The McMaster-Carr viton encapsulated silicone inner coolant seal o-rings split in one spot so I am back to using stock non reuseable on this engine.

 

monkey, run atkins or stock seals and 1oz/gal of premix.