RETed

"J" stands for "jacket", and it has to be compromised.





-Ted

Lynn E. Hanover

The "J" bridge port is available from most of the major shops, and is legal in SCCA racing because "as per the rules" no material may be added to the engine.



The "J" bridge port leaves the outer wall of the "O" ring groove in the rotor housing intact so as to seal out the coolant. No material is added to the engine.



The port shown in the hyperlink is a "Monster" bridge port, where the rotor housing is filled with epoxy. The runner includes the epoxy as one wall.



Since material must be added to manufacture this port, it is not legal in SCCA and other forms of racing.





Lynn E. Hanover

rx7_re

One thing I have always been curious about...



Do you actually put an inner coolant seal in there or do you just run without one. I could see cutting one up so it will not obstruct the port. I dont know what goes on there so could someone clear that up for me. Thanks

FrostRacing

it seems to me that notching the rotor housing may catch the apex seal has this ever happened?

Lynn E. Hanover

The inner compression, or, water seal "O" ring is cut just short of the port opening. Some people put in a roll pin to block the groove just short of the port. I drive a sharp punch that I have ground just the width of the seal groove, into the floor of the groove, and stand up a burr of aluminum to block the groove. When the engine is assembled the "O" ring gets compressed and the ends will extrude into the port if the groove is not blocked. I also add a dab of silicone to fill in the open end of the groove. I can take some pictures if you want.



I have used teflon insulated 18 gage aircraft wire and a slight amount of silicone for this seal. A friend just uses regular crap 18 gage hook up wire and silicone.



The outer seal (the black one) can be reused several times, as is true of the teflon coated wire. The black seal just needs to be shortended a bit, so I cut it at a 45 and add a dab of silicone to the junction. I put the junction at the top of the engine, so any leak shoud be visible. But have never had one leak yet.



I love silicone.



Was that clear enough?



Lynn E. Hanover



lehanover@aol.com

rx7_re

Thanks Lynn, just what i wanted to know.

Lynn E. Hanover

For the race engines, the apex seal is one piece, so there is nothing loose on the end to (in effect) fall off into the notched out part of the rotor housing. In the 13B I think Mazda is up to maybe 4 styles of apex seal. For a bridge port the three piece is probably out of the question because either the inner or the out half of the lateral element will not have a part of bridge to support it, and eventually a piece will slide out into the port and get snapped off. So, only the solid one piece or one of the two piece designs are servicable.



One design has a triangular corner piece that would seem well enough supported to work well. The end would be supported between 30% and 50% by the bridge and the main part of the apex seal covers that corner piece where it would interface with the notch. Another design has that end piece being of some length with a junction in the face of the seal.



The edge of the notch would have to be well outboard of this junction lest the high unit pressure wear a groove in the housing.



Since the wall of the center cast iron is thinner than the end plates, that bridge is generally left a bit wider to reduce the chances of cracking. I don't work with the metal seals at all, so this is speculation, but I would run the loose ends against the center iron, just to get more support for the corner pieces. So you have carbon, or ceramic, or 2 piece with a small loose corner piece, or a 2 piece with a big corner piece, (if the notch is small enough) but not the 3 piece.



If you super glue the corners onto the main part of the seal, you can install them any way around with ease. The loose ends won't ( most of the time) pop off and vanish on the floor.



The super glue fails in the first few seconds of operation, and everything is then normal, sealing wise.



Lynn E. Hanover



lehanover@aol.com

Latin270

Old thread....I know but does anyone have pics of a J-port w/ the water seals attached???? Its just a tad confusing w/o a pic or two! Thanks!

C. Ludwig

That wouldn't be a j-bridge. That is a standard bridge port. Here is one of BDC's ports. Hope he doesn't mind.

Latin270

Beautiful!