Zero Clearance Side Seals

Barry Bordes · 03-28-2008, 05:45 AM

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

Chadwick · 03-28-2008, 07:37 AM

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

Dan

cewrx7r1 · 03-28-2008, 09:23 AM

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

tom93r1 · 03-28-2008, 10:19 AM

Thats kind of a cool idea

Barry Bordes · 03-28-2008, 11:29 AM

Quote:

Originally Posted by cewrx7r1

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

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

Signal 2 · 03-28-2008, 12:59 PM

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?

Barry Bordes · 03-28-2008, 02:55 PM

Quote:

Originally Posted by Signal 2

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

GoodfellaFD3S · 03-29-2008, 05:31 PM

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.

Barry Bordes · 03-31-2008, 07:19 AM

This is the way to get a precision cut.

Barry

***Herblenny*** · 03-31-2008, 01:58 PM

Pretty neat barry!

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

a7xh7 · 03-31-2008, 09:43 PM

seems cool..

cewrx7r1 · 03-31-2008, 11:43 PM

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?

Barry Bordes · 04-01-2008, 07:24 AM

Quote:

Originally Posted by cewrx7r1

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

Barry Bordes · 04-02-2008, 07:08 AM

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.

afgmoto1978 · 04-04-2008, 07:32 PM

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......

03-28-2008, 07:37 AM	#2
Chadwick Rotary Fanatic Join Date: Feb 2008 Location: Smyrna, TN, USA Posts: 239 Rep Power: 18	The problem I see is the chance for the side seal to get jammed and loose compression on one face. Dan __________________ 93 RX7 BB (Race Car) 93 RX7 SSM (Soon to be IBM and a daily driver) 05 Silverado Z71 08 Mini Cooper 80 LS RX7 (for sale)

03-28-2008, 12:59 PM	#6
Signal 2 Viable Fossil Join Date: Mar 2008 Location: Mid-West Posts: 199 Rep Power: 17	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? __________________ Jim VR R1 FD Last edited by Signal 2; 03-28-2008 at 01:07 PM.

03-31-2008, 07:19 AM	#9
Barry Bordes Rotary Fanatic Join Date: Feb 2008 Location: Slidell, LA Posts: 191 Rep Power: 18	This is the way to get a precision cut. Barry Last edited by Barry Bordes; 08-28-2015 at 11:35 AM.

03-31-2008, 01:58 PM	#10
*Herblenny* Founder/Administrator/Internet Pitbull :) Join Date: Jan 2008 Posts: 644 Rep Power: 10	Pretty neat barry! So, are you going to be ready for DGRR?? __________________ DGRR 2013 - Year of 13B www.DealsGapRotaryRally.com http://www.facebook.com/Herblenny

03-31-2008, 09:43 PM	#11
a7xh7 Rotary Fan in Training Join Date: Mar 2008 Posts: 88 Rep Power: 0	seems cool.. __________________ "sevens_ix"

03-28-2008, 09:23 AM	#3
cewrx7r1 The Judge Join Date: Feb 2008 Posts: 196 Rep Power: 17	Mazda's race prep manual lists .0039" to .0059" for 13Bs. But this is from 1996. I do not know if this has changed.

03-28-2008, 10:19 AM	#4
tom93r1 Rotary Fan in Training Join Date: Feb 2008 Posts: 45 Rep Power: 0	Thats kind of a cool idea

03-29-2008, 05:31 PM	#8
GoodfellaFD3S Rotary Fan in Training Join Date: Feb 2008 Posts: 40 Rep Power: 0	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.

03-31-2008, 11:43 PM	#12
cewrx7r1 The Judge Join Date: Feb 2008 Posts: 196 Rep Power: 17	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?

04-02-2008, 07:08 AM	#14
Barry Bordes Rotary Fanatic Join Date: Feb 2008 Location: Slidell, LA Posts: 191 Rep Power: 18	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.

04-04-2008, 07:32 PM	#15
afgmoto1978 Rotary Fanatic Join Date: Mar 2008 Location: Portland, Oregon Posts: 381 Rep Power: 17	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......