It seemed their was a clearance issue when installing the Renesis rotors
  in a 13B engine.  Do you recall what it was?  I think the gears, and
  bearing may be different as well.

  Doug in Japan

  News to me.

  Paul Lamar



 Paul,

 I'm planning on using Renesis 10:1 rotors in my p-port 20B.  As I
 understand
 it, I will need to cut the apex grooves deeper to accept the 13b/20b apex
 seals, and use only one of the oil scraper rings.  And of course, have the
 assembly rebalanced.

 Mark S.
 Austin

 http://www.rotaryeng.net/history.html

 Why not run stock low height RX8 apex seals? They have less weight than 13B
 seals so they will follow variations better. Also the RX8 corner seals
 have a very low friction Diamond Like Carbon coating. DLC should be
 applied to all the seals but I think Mazda choose only the corner
 seals to keep the cost down. Seal friction has a significant affect
 on engine efficiency. Particularly at the higher RPM ranges we run.

 Paul Lamar


 Paul,

I was under the impression that there was a risk of the thinner apex seals
catching when passing over the p-ports.  If this isn't the case, then I
agree, go with the Renesis seals.

Mark S.

No the 2 mm seals have been used for year with peripheral exhaust ports
with no problems. The peripheral exhaust port is far harder on the
apex seal than a peripheral intake port. A little slot opens up and you
have high pressure, very high temperature gases shooting out of
there at supersonic velocities. That is the main reason you need apex
seal oil. The apex seal oil cools the apex seal.

By contrast there is no pressure difference across the apex seal
as it passes over peripheral intake port and the apex seal is cooled
by the incoming mixture.


There is another subtle  advantage to our intake p-ports in that they are oval
so the apex seal is introduced to the opening gradually compared to
what happens in the rectangular exhaust port.

Paul Lamar