let's leave the side seal out of this completely...



what do you think is the absolute minimum amount of support you could get away with giving the corner seal when you're advancing the intake port timing?

I tried up to 30% exposed, but that still supports the leading end of the side seal and gets the bridgeport kind of thin and prone to cracking.



Way advanced early opening (if that is what you are after) is getting closer to a bridgeported engine.



During the IMSA racing stock years, bridge porting was disallowed, so interesting substitutes came to pass.



The finger port and keyhole port were popular. Where grooves are cut into the port face toward the intake to allow additional flow and the grooves are more narrow than the width of the corner seal, so it is supported. The fingers were triangular with the wide flat side to the rotor and a sharp end facing the intake.



Dave Lemon used to race in that class and provided the SCCA (Secrete Car Club of America) with the pictures for the E production engine rules that also limit port shapes to covering the junction of the corner seal and the leading end of the side seal.



This finger port along with the stock 4 barrel (Niki I think) was a very potent package for a 12A back then.



The best E production (13B) engines prior to the rule change were getting about 229 HP with a wide power band.



There were some pictures of these ports on this site, or links to them. Check Dave Lemon or Mazdatrix sites as well.



If you have a small milling machine and a lot of time on your hands, You could notch a set of corner seals so that a reverse notch at the ends of the side seals would sit into the corner seals a bit. Now drill through the

the rotor face, through the corner seal well and out the other side. You would want to make up a good stiff jig to use for this. Keep the hole low enough that the hole does not affect the apex seal.



Now you have to limit the corner seal from protruding beyond maybe .0025" over the housing thickness. Install the corner seal in the hole and drill it through the first hole.



Clean up the whole mess and install the springs and such as usual. Insert drill rod pins through the hole so as to trap the corner seal in the hole with a limit of the .0025" extension (beyond housing thickness). Peen over the holes so the pin cannot escape.



Now the closing line will require a very nice radius to keep things together at lower RPM. But the corner seals and the side seals cannot fall out, and how big the port open side is no longer matters.



If some of the IMSA guys were not doing this I would be shocked. So if you just stick a mirror into the port to check for (no bridgeport) you won't see one at all. Some of those engine were way stronger than others, and were stopping for fuel more often than others, indicating BSFCs lower than .665 or thereabouts.





Lynn E. Hanover

that sounds neet, but i can't grasp it. damn it I usually get these things. i go, i go, it's off to search i go!

I should have said "BSFCs above .665. Sorry.



First you limit how far the corner seal could stick up out of its hole. So it cannot be damaged as it crosses the closing line. You could pin it as above, or drill and tap a hole at a steep angle that intersects the corner seal hole. Notch the inner side of the seal and assemble it in the rotor. Screw in a set screw so that the end of the screw enters the notch. So now the corner seal can only raise up until it runs into the screw point.

And the screw could then control how far the seal can move.



Now flycut the seal where the side seal would normally touch it. Make the flycut tall enough that half the width of the seal could fit into it. Then notch the end of the side seal to sit in the flycut.



Now the corner seal cannot fall into the port, but it can still articulate and seal as normal, and it prevents the side seal from extending beyond the face of the corner seal. Nothing can fall into the port.



Could be good for a turbo engine, but huge port openings in NA engines tend to slow velocity and move peak power way up the RPM range.





Lynn E. Hanover

Here is a picture of the side seal restraint system. I have never done this. I think it would work. I do not know that.



Lynn E. Hanover

Lynn I would like to present you this on behalf of a grateful Rotary Nation... https://www.nopistons.com/forums/pub...#>/bowdown.gif



Now where did I put those damn oversized sideseals? https://www.nopistons.com/forums/pub...1047683561.gif

I get the idea and very intuitive it is. What I did not see is what was holding the retaining pin from coming out? Use a roll pin?

Sorry, I overlooked your question.



The rotors are cast nodular iron, and dent easy unlike the rather hard castings of the rotor irons.



If you establish how much extension you want and then make a jig to guide the drill bit, so as to get the same outcome on each corner you could just use a length of drill bit shank as the pin and leave one end of the hole blind, and once the pin is installed, peen over the hole slightly, and that will hold it just fine.



The angled 6-32 threaded hole idea would give you an adjustment to control corner seal exposure and it would require no drilling jig.



You can also straighten slightly bent tips around corner seal holes and damaged apex seal slots.

The material can be TIG welded with a mild steel filler rod with good results.





Lynn E. Hanover



Picture is the Lear jet in the game room. Note the airline seats to watch airplane movies on the big screen.

Awesome thinking outside the square Lynn, im lovin it.



But with the pinning it idea how do you allow some movement of the corner seal? Use a pin slightly smaller than the hole?

Yes.



Lynn E. Hanover