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


       Diesel works amazingly well to remove carbon... might even try
   oxalic acid for rusted together parts....or CLR...

       Dan Gorsline.

   I have been involved over the years in salvage and restoration of old
   hit and miss and one lung diesel engines. We have been amazed
   at how well JET B works. It seems very corrosive, and the rust just
   falls away. Warmed up it finds it way into every crevice, and a few days
   later the parts undo fairly easy !

   Steve Carlisle


    well I've tried to gasoline ,kerosene and right now it is soaking in jet a which basically is high grade kerosene.

    The seals are still stuck in place, nothing has budget all.

   I even tried a ultrasound cleaner with gas in the bath, no luck all seals still stuck

   David Mikesell

MEK is the most powerful solvent I know of. Acetone is a close second.
I hesitate to say warm it up for the explosion or fire possibilities.

HOT ATF might be OK.

Paul Lamar


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