sen2two

I have access to a CNC mill, manual mill, and many other machining equipment. I am in school for machining and think this would be a great experiment. Can i just make an exact replica of the stock Mazda seal, but one piece of high grade steel. Then send it out to be heat treated?



I know i can do this and get it to at least .001" or better on a manual mill then clearance it later by hand to fit perfect. But what about the edge of the seal that touches the housing? Is there a certain radius that it should be rounded to?



I wanted to try to make one set out of chromoly then send it out to be heat treated. But i think it might be to heavy. I think aluminum would never withstand the heat, even the high grade stuff. Any reccamendations on a material?

yellowsnow

mazda has a special way of doing the sales.

i forget what it is but the seals that dont last long are the kind that are GROUND to size

but your using a cnc machine so its more of a fyi.

also there seals are made of different metals and this maybe a expensive experiment

why dont you try titinum and heat treat it and then cryotreat them as well?

levelzero

I think I have the SAE paper somewhere. Basically Mazda cryotreated the seals using some sort of laser in order to get the temps down to near absolute zero. Yes I know it sounds counter intuitive, but it has something to do with bouncing the laser to pull heat away from the part.



Making a stronger seal is going to be hard to do, but you can aim to make a lighter seal which will allow you to rev higher.

mazdaspeed7

Titanium is a bad choice. It expands greatly as it heats up, and does not wear well. It just tends to gall.



Sen2two, you wont be able to mill the seals to size and get an acceptable tolerance range. You will need to be in the ten thousandths range, and for that, you will need a surface grinder. Besides, the tooling marks from machining will create localized stresses and failure points.



The material choice and heat treating are what make or break steel seals. Mazda seals are cast iron thats nitrided on the wear surface. The cast iron is dimensionally stable over a broad heat range, and the nitride coating allows the seals to last a long time. If you wear through it, the cast iron is soft enough to not shred rotor housings. They are somewhat brittle though. Aftermarket seals range from soft steel seals that dont break, and harder steel seals that dont wear much, and can be rough on housings, but are very resistant to detonation.



Carbon apex seals are actually a suspension of carbon particles in an aluminum matrix. They are very light, and produce practically no wear, and minimal damage if they break. They are a bit fragile for a turbo engine though.



Piston engine rings are almost always cast iron with a wear coating. Its just proven itself as an effective means of sealing in combustion. Kinda hard to outsmart decades of the smartest engineers coming to the came choice for a sealing material.



Apex seals are not a good starting point on the learning curve.

Trots*88TII-AE*

I agree with the above. You could maybe consider starting with a pair of junked rotor PP housings? I always wanted to make some.

j9fd3s

make the shaft!

sen2two

The seals will be going into a junk motor. housings are on the line of usable and paper weight. plates, are just good enough to use also. Motor will be an experiment for a few things I'm making.If they turn out OK, They will go into my "good" motors.I will be going through with this. I'm not looking to compete in the market. Unless i stumble across an awesome design. These are really just for me. I enjoy making my own parts. There's a certain pride in that.



I have been doing a lot of research lately on what kind of material to use and i have a few ideas, as well as talking to my instructor about this.He knows nothing about rotary or apex seal design, but he has been a machinist for over 40 years. I glued a stock 3 piece seal together today and laid it out. I'm going to make a test one in aluminum just to see if i can get it into spec on a manual mill. I will also make one on the CNC.



Motivefab, I'm curious as to why you would say i cant get it within .010", I have gotten plenty on parts withing .001" with the very same mill i will be using to make these.And with the right tooling, speed, cutter, set-up, there should not be any tooling marks. Especially on a CNC. When done right, a CNC can leave a polished finish even on rounded edges.









My main concern is the contact area on the seal. I am unsure of what radius to give the seal where it meets the housing.

sen2two

I'm working on something, not a new shaft, but mating the two together. What would that make?





I'll be starting a new thread on that soon enough.

mazdaspeed7

Not .010 tolerance, I mean closer to .0001"



I like making my own parts too, but some things are too specialized to be pulled off even in a well equipped machine shop.

sen2two

I wasn't saying you were wrong. Just asking why...



I do have access to a surface grinder, but with my experience, they can't compare to the tight tolerance that a mill can give.I doubt that the seals need to be withing .0001" anyways. Looking at Mazdas tolerances in other areas, There's no reason why that one would be so close. Most people that build full out race motors still have to clearence the apex seals and apex seal slot anyway.



Either way, these will probley only see my motors, and maybe a few friends of mine. But that's really it.



If anyone wants to add any advice on doing this, or not doing this... feel free. I will not take it the wrong way.