Hi Paul, what is the best way to get the seals on the rotor, Apex
seals,   side seals  out without damaging them. The ones in this old sachs rotor
 are stuck and I don't want to tear apart to get them out.

 David Mikesell

 Soak it in solvent for 24 hours. Gasoline or MEK or acetone or even
 kerosene.
 For some strange reason auto transmission fluid sometimes works.

 BTW the Sach is a good engine to do R&D on apex seals.
 Try glass filled teflon. Back in the days Mazda was doing
 research on the subject that was not availably.

 The oil squirter should keep the rotor temperature well below
 500 F.

 Perfect for the side seals as they run nowhere near the temperature
 of the apex seals.

 Paul Lamar


 Well I plan on using the addition of the oil squirter so I can
bring the
 temps up to get more hp out of it.

 You think the glass filled teflon will work for apex and side seals? I
 would think it might get wedged or stuck in the slots. I would guess
 even though it is glass filled still a bit soft though.

 If it would work that would be nice to have a all aluminum housing that
 will last with nice affordable seals that will last too.

 David Mikesell

 This carbon filled Teflon is looking great. I suspect the aluminum side
 housings can be
 simply anodized and that is it. Much cheaper than any type of
flamed sprayed
 coatings.

 Paul Lamar


 Hi Paul and all,
 a friend of mine here in OZ has just supplied disk brake rotors to the
 navy made from 6061 T3 with a hard anodized coating that is rated
at 800
 Brinell, which is about 85 Rockwell. This makes it about 2 times harder
 than cast iron. Should be fine with a lubricated rotor running over it,
 especially with carbon filled Teflon seals.

 He did point out that to get a good anodized surface, 6061 T3 is needed
 as the surface will not finish well with cheaper grades due to
 impurities in the alloy.

 So, I think that means we must mill the housings from billet.
 FWIW,

 Dave Mccandless in OZ

 Well we are planning on  milling  the housings from billet.
 No castings. The RB's are castings.


 Paul Lamar


The carbon filled potential nylon probably won't work. In the literature
it says it will hold
up at 900 fpm and up to 2500 psi non-lubed and 3500 psi lubed. The distance
around this small rotary housing is more than a foot, so the limit would
be 900 rpms.

David Mikesell

Not the apex seals. The side seals go about 1/3 rd as fast in a complex
rotating and
translating pattern.

And Teflon "glue" not nylon. Nylon is only good to 200 F. Teflon is good
to 500 F

Still worth a try for side seals.

There is no beating a silicon nitride apex seal except for the cost.
Since the rotor is rotating even the apex seals do not rub at 900 fpm at
900 RPM.
Something less.


Paul Lamar

I wonder what the Apex and side seals are made from in the Sachs rotary.

 With the housings being all aluminum and hardly any scoring marks,
except for the damage caused by something getting inside with the rotor,
the surfaces look pretty good.

David Mikese

Me too. They look strange.

Paul Lamar


I got it wrong, the alloy is 6061 T6     not T3

Dave Mccandless in OZ

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