Zero Clearance Side Seals
 

I like to set up my side seals as tight a practical. There are different thoughts on this minimum spec.
I have seen recommendations from .002” -.004” for turbo applications.

On my last engine build-up I mistakenly switched two side seals causing a
.002” clearance. This resulted in scrapping the RE front plate because of a
.004” wear groove on it in the area of combustion (where heat/expansion is greatest).

I decided to try .000”! Found this in an early Mazda paper.

What do you think?
Barry

The problem I see is the chance for the side seal to get jammed and loose compression on one face.

Dan

Mazda's race prep manual lists .0039" to .0059" for 13Bs. But this is from 1996.
I do not know if this has changed.

Thats kind of a cool idea

Yes Chuck you are right, but the regular workshop manual states .002"-.0059" and Racing Beat recommends .0015”-.004”( this may be a NA spec).

I guess I should have said it runs gap-less. It still has clearance to expand into the added corner seal slot.

Barry

Just thinking out-loud here....and I'm in the middle of only my first rebuild so go easy....
What about potential carbon build-up in that corner seal slot. I see some clearance for length, but is there risk with loss of what little "side" clearance there is within that slot due to expansion and/or carbon? What would be the result of the side seal and corner seal being effectively fused together if that happened?

My swag (scientific wild ass guess) would be that it wouldn't much more of a problem. I'll have to tell you in a couple of years.


Barry

I'd have to go check the feeler gauges, but I'm pretty sure I clearance side seals at .0015 to .002. Nice and tight, and havent had a problem yet. Of course, we recommend a pretty long breakin period of 1500 miles before serious boosting.

This is the way to get a precision cut.

Barry

http://i287.photobucket.com/albums/l...algrinding.gif

http://www.rotarycarclub.com/attachm...7&d=1206964763
Pretty neat barry!

So, are you going to be ready for DGRR??

seems cool..

Those special coner seals should seal better, but where can you buy them?
If you had a good machine shop, maybe you could make them yourself.
The question is, where they not cost effective for Mazda, or only used in rcae engines?

Yes Chuck, I am not sure why Mazda hasn't used them for production. Possibly the extra machining and fitting.

I also wonder if the reason could be that the normal blow-by of the side seals might help to float the rotor between the housings.

As for who makes them, I make them myself with a special diamond cutting tool. I can cut a set for you.
Barry

Phil, thanks for installing the picture correctly for me. How do you do that?

Barry

And I am still building my engine but expect to be there. I may have to go with Jack.

Barry,

Neat idea, but what about Apex seal clearance, assuming you had more clearance at the apex seal (two faces) you would see unwanted binding at the side seal from the apex seal rotating at the point of peak combustion pressure. Only one way to find out, and that's to test it out.

If money was no object, zero clearance on everything after Nikasil coating, or something of similar low friction properties. Ceramic coating......