I have no complaints about them at all and I do abuse my daily driver... Also the scratch comparison does not cut it for me at all... Ceramic holds better under heat but you can still scratch ceramic with metal...

Quote from RE site:

I don't see anything saying that the treatment has anything to do with hardness but with temperature...

Reading does wonders guys...

 

1. Depends on the ceramic, you cannot scratch a solid piece of a harder material with a softer material under normal circumstances.

2. I was not refering at all to the superseals, but regular old RA seal, which for some reason have had a stupid internet myth attached to them that they are harder then stock when they are in fact many times softer then stock. I never implied the scratch test had anything to do with how well the seals hold up in an enigne or how resistant they are to heat, only that the RA seals are softer then the unharded portion of a stock mazda seal.

No one implied anything fo the sort. In fact tho, nitriding will effect the hardness of the seals but that is a moot point


Yes it does, try it.

 

you believe?

if you're not testing, you're guessing.

 

No, I know the what hardness hardened cast iron can achieve. I also have documentation that the top 3mm of stock apex seals are elctron beam chill hardened.

It is irrelevent anyway, as I've allready proved that RA seals are softer then the 40 rockwells of the lower portion of stock seals, Ths means they are way softer then the hardened portion.


For anyone who doubts the validity of scratch testing, or thinks something silly like they can scratch carbide with a sharp piece of aluminum,.. Here is a nice set of hardness testing files with instructions on their use.

http://www.1gg.com/html/body_hatesters.html

 

just about anything sharp can leave a scratch on just about anything flat.

 

drago86 is correct the top 3mm of the seal is 60+ RC and yes this was tested locally. The bottom portion of the seal is between 40 - 45 RC.

 

The only way to know is for someone else to do what I'm currently doing with my Fc. Rebuild an engine with these seals, take pics, and re-open the engine at a certain mileage for inspection. I have 4k more to go on my engine with original RA seals before I pull it apart again at 10k. Now because one of my re-used housings were already scoured from the previous apex seal breakage, I have a better reference point to look at when my engine is pulled apart again. I will be able to see if the seals have worn the housings smooth to the point that the old grooves are gone.

 

he said he scratched one seal with the other.

 

Yes, The nitrite coating is the topic. One that I have been asking questions about. Nitrideing can be a coating and it can be more than a coating. It can actually penetrate into the crystallin structure of the steel. With certain proccesses, quite deeply.

A shallow coating will offer nothing in wear characteristics after the coating is wore through.

Drago re-enforces my point with the hardening of the edge of stock seals. Which I will personally try to measure this week. The hardness goes through the seal and doesn't get wore through.

Once again my question is what proccess is RA using. Signifigant depth of nitride cannot be reached in a finished piece like a seal without distortion. A 2mm seal with a significant depth of nitride would have to be made a little over sized and then machined afterwards to take out distortion. Probably wouldn't have that nice black appearance.

Thin coating = marginal initiall gain. Then no gain.

 

omfg why do you think this it is just plain wrong. Do you not believe in Moh's hardness scale? Or that the hardness testing files thousands of people use actually work?

http://66.102.9.104/search?q=cache:T...s&ct=clnk&cd=8


On the nitrided seals, I really dont see how the nitride layer is going to be helping repel heat, or increase the thermal conductivity at all. It will end the extreme housing wear from the seals due to galling and scuffing ( I just tore my motor down with ~20k on it and am NOT happy with the extreme gall/scuff wear to the housings) the nitrided surface will be much harder and have a much better coeficient of friction. When the automitive industry first started using ductile iron/steel rings they had the same problems with galling/scuffing due to the much softer rings as compared to the normal grey cast iron rings. They fixed this by using chrome or moly facings on the rings. I kinda suspect this is what RA is doing, Not acknologing the wear problems, but introduucing a new seal that fixes them. From what ive seen of RA seals they are just spring tempered steel, which explains why they dont break.


Depending on how deeply and what process they are nitrided by the coating could last quite a long time. The base alloy they start with matters alot for the final hardness of the nitrided layer too. If done right though they can achieve around 900-1000 HV which is very close to the 1100 HV hardness of the housings.

 

come on dood, use your head. i didn't say it would hack right through it.

 

Doesnt matter, its not going to scratch, go now find a piece of aluminum and try to scratch a piece of glass (NOT COATED GLASS LIKE AUTOMOTIVE), or a carbide cutting tool, or a steel knife blade.

 

"Hardness can be tested through scratching. A scratch on a material is actually a groove producedby microfractures on the material surface. It requires either the breaking of bonds or thedisplacement of atoms. A given material can only be scratched by a harder substance. A hardmaterial can scratch a softer material, but a soft material can not scratch a harder one (no matterhow hard you try). Therefore, a relative scale can be established to account for the differences inhardness simply by seeing which material scratches another. This approach was proposed bythe French mineralogist Friedrich Mohs almost one hundred and seventy years ago. The MohsHardness Scale, starting with talc at 1 and ending with diamond at 10, is universally used aroundthe world as a way of distinguishing minerals and materials. Simply put, the higher the number,the harder the material. It is a fast and easy test which can be performed in the field. The scale isgiven below. It has recently been extended to included 15 gradations rather than the standard 10"

^ excript from a basic (like 7th grade basic) materials lab i found on the web
http://www.stevens-tech.edu/engineer...nual/lab_1.pdf

And regardless the point is you claimed that the fact that I compared the hardness of stock and RA seals by using a scratch test was completely irrelevent because " i can scratch a piece of carbide with a sharp piece of aluminum", when is is in fact impossible. If you can do this I suggest you stop wasting your time on the forums and redirect it twards writing a paper disproving basic scientific/engineering principles.

Furthermore you seem to refuse to acknoledge that scratch testing is one of the most common forms of relative hardness assesment used. That is why they sell hardness testing files. The files have a graduated hardnesss and you try to scratch your sample pieces with each file, when it does finally scratch you know the hardness falls between that file and the next softer file you tested with previously.


PLEASE spend some time actually reading my posts and not blindly replaying with the same thing i have disproved ( not to mention common knowledge disproves it,..)just to save face


Think of the kids man,.. you dont want some kid to read your posts and go around thinking he can scratch carbide with aluminum and his science teacher is wrong do you??? Thats how fast food employee's are made,..

 

HV = Hardness Value? Are you talking Brinnell? Chroming, even with alloys, is no where near ceramic or diamond. I think the hardest chrome plating alloy I have dealt with is ~55 Rc. I don't have testing files. If the chrome (or any metal) can be cut with a standard file it is less than 60 Rc. I always thought the chrome on the housings was not that hard and was used mainly for it's naturally low coeffecient of friction.

You seem knowledgable in this area. Educate me.

Well I suck at splitting up quotes too! Internet police give me a break!

 

I don't believe the hardness of the RA seals really matters to us.

For example, ceramic seals are harder than even the stock electron beam chilled seals and they wear the rotor housing surface much less.

What is known from many users input is that for whatever reason the RA seals wear the rotor housings more than stock seals.

I have heard 2nd hand from a reliable source of a well known drag racer who tried RA seals and destroyed a set of rotor housings in one engine dyno session (high rpm engine).

I have seen pics posted on this forum of an engine w/ very low miles and extreme rotor housing wear.

I decided that more lubrication between the RA apex seal and the rotor housing has a pretty good chance of lowering the amount of wear.

Premixing oil into the gas in addition to the stock oil injection seemed the best way to introduce the lubrication, but how much oil to add?

Two strokes premix as much as 16:1 parts fuel to oil!

Racing Beat recommends 29:1 ratio on a 600hp 2 rotor using stock (low wear) seals.

The limiting factor on how much oil to introduce for me was the drop in fuels octane since my car is turbo.

I decided on trying ~50:1 since that drops the fuels octane by almost 2 points and I reasoned I could keep the engine together at 15psi on 89 octane based on my past experiences.

This turns out to be a quart of premix with 12 1/2 gallons of fuel, so I just dump in a quart when I fill the gas tank.

I had my last engine apart that ran this ratio premix for ~3,000 miles and it was nice and clean with much less carbon deposits and varnishing than running no premix.

My next enagine will use ceramic seals and much less premix since premix oil is expensive and bad for us

 

More lubrication is definatly what is needed. My housings are trashed after less then 20k. The wear is definately galling/scuffing adhesive type wear. The material they are using for their classic seals is just plain not suitible imho due to excessive wear. That was what i was origonally trying to convey , RA seals do not wear the housings because they are harder, infact harder seals generally means better friction/wear properties for thew whole system. If they were harder they would most likely wear less.

Tony HV is hardness vickers, I got that spec from a mazda SAE document that was avaliable on the web a while back. 1100 HV is ~70 on the rockwell C scale. Let my try and find it and post it up.

 

thw whole pdf is too big to post

 

Drago, please e-mail the info to me to. tonydelia@charter.net.

I thank you.

 

Sorry for the delay, I went camping. I sent everything i have; Tony, your E-mail was bouncing tho.

 

i would just like to say, we use these super seals in a lot of our engines and have had wonderful success. you always have to be sure you check the tolerances with these tho. every rotor is slightly different and these seals are a tad on the thick side. a little sanding goes a long way to making sure there is no binding and therefore no excessive wear.

hell, one of my buddies has cracked 3 rear plates on his s4 TII setup because of severely high egt's (he refuses to get a tune ) and yet these seals have been perfectly fine and slapped back in for every rebuild with perfect compression results.