metalliman

Has anyone ever tried eliminating the bridge in a bridge-port? I know under normal circumstances, the corner seals would pop out, and I'm sure the apex seals and side seals would be ruined too. What if you were to make a "one piece side seal", to replace all three side seals, and corner seals on each side of the rotor. This would also require the macining of each rotor where the current side seals are.

The reason I ask, is because I'm a CNC machinist, and I may be getting a hold of a junk 12a out of a 84 rx-7. I'm considering making a one piece side seal, probably out of 1018 Cold Roll Steel. This seal would have three notches machined for the apex seals, and matching notches would be machined in the the carbon apex seals, so the apex seal couldn't slide from side to side on the rotor. This seal would probably be about 3mm wide, due to the fact that it would be too difficult to mill a slot much narrower in the rotor it self. Also I would probably drill and ream a 3/16" hole on the rotor where each corner seal used to be, and press a dowel pin inside. The one piece side seal would have matching holes with a .002" slip fit for the dowel pins. This would stop the seal from trying to spin, and stop it from placing lateral force on the apex seal.

Of course I'd would somehow have to get a hold of some different springs for the side seal, being that there would be much more surface area touching the side housings, a much more powerful spring would be required.

So now my question is again, has anyone ever proposed, or tried my idea? Does anybody have any criticism (hopefully constructive) about my idea, or any problems?

Directfreak

iTrader: (2)

Sounds interesting. I don't know if the eliptical orbit of the rotors would allow it to work. Post your thread in the "Single Turbo" and "Rotary Performace" thread to get some more insight.

RotorMotorDriver

iTrader: (1)

Sounds like a good idea, and I was looking at the rotor I have on my desk "visually thinking" and it occured to me... What benifit would this have? By cutting out the bridge you are trying to obtain better flow, but wouldnt the fact that the corner seal is even there block the same flow the bridge would block?

~T.J.

EDIT: I just re-thought about it and realized that its not like the corner seal is there constantly, so since its only passing over the port for a fraction of a second or whatever, you actually could get more flow by removing the bridge and making a 1 piece side seal with intigrated corner seals. Sounds like a badass idea if you could get it to work!

metalliman

I'm thinking the increase in horsepower would be quite substantial, due to the fact that the port is obviously larger, and because there will be less surface area around the port, which means less friction, and less turbulence. I don't know how the wider side seal, (3mm) will perform though. The stock side seal is only 1 mm thick I believe. Obviously it will take much longer to break in. I'm also not sure as to what I could use as springs for the seal.

mperformance

yeap it all sounds great, but the reason why you need all of those seals separated is due to the fact that the surface is irregular and one huge seal will not seal properly.

metalliman

What do you mean, the surface is irregular, the side housings should be flat, assuming they're not warped our gouged out from previous wear. Just to be sure, I'll have to surface gring the side housings when I have the motor apart.

metalliman

Anybody else have any criticism, I'm seriously considering going ahead with this project soon, and I would like to know if anybody can think of some problems with my idea. Anything that would stop me from going forward, something I'm overlooking, anything?

rxseven

You can't use a one piece seal because of the number of degrees of freedom needed for each of the seals and the heat expansion that occurs. Also 1018 crs is not hard enough and will wear out in no time.

mperformance

it looks flat metalliman, but it's not...microscopically that is.

thermal expansion is another important issue as rxseven pointed out.

Those two reason should be obvious. I'm sure there are more reasons like the actual seal weight issues and rotational forces acting on the strength and durability of the materials used at high rpms.

also look into vibration problems at high rpms.

I think the shape of the one piece seal would be important to deal with.

metalliman

I understand, thermal expansion could be a potential issue, I'll have to look up some thermal expansion coefficients to see how much additional clearance will be needed. Obviously, if the amount of expansion is too great, I'll never be able to get the seal to actually seal.

As for the flat issue, I'm still not sure what you're talking about. If I grind the side housings, they'll be flat within .0002". I consider that pretty flat. I understand that on a microscopic level the side housings are porous, but this shouldn't affect the one piece seal any differently than multiple seals.

Does anyone know what material mazda uses for their side seals or it's approximate hardness?

Rxseven, can you be more detailed as to what you mean by degrees of freedom for each seal?

DriveFast7

iTrader: (1)

the apex seal and corner seals need to flex independantly from each other. that's why each are spring loaded independantly.