Subject: Junk parts
From: Rotary Engine
Date: 3/27/2007, 8:47 AM
To: AARotary Engine



    > > Well, we just got the engine from the 87 RX7 apart. We haven't
    > cleaned
    > > up the parts, and it looks like we might not have to - at least the
    > > rotors and e-shaft. At first glance, it looks like the rotor
    > housings
    > > might be OK. The end and intermediate housings look like they
    > will have
    > > to be lapped & re-nitrides.
    > >
    > > I have attached some pix of the e-shaft and rotors. Looks like we
    > have
    > > had a coolant and/or lubrication failure. What do you guys think? I
    > > think the e-shaft is junk.
    > >
    > > Can the Babbitt be replaced in the rotors or are they a total loss?
    > >
    > > Good thing I have three more engines on the way. :)
    > >
    > > Doc Custer
    > > Retired Software Engineer and sometime Audiologist
    > >
    > > That is a fine looking engine Doc. Somebody ran it low on oil from
    > > the looks of it. I would polish the front rotor journal
    > > with 600 grit or 800 grit emery cloth and press out the old
    > > bearing shell in the front rotor of course. Check the oil passages
    > > in the e-shaft and make sure they are not plugged up. From what
    > > I can see the rotors are in fine shape. Take some more pictures
    > > of the rotors out of the engine. From what little I can see even
    > > the rotor housings look OK. If no apex seals are broken you have
    > > a flyable engine there IMHO.
    > >
    > > Finn Lassen ran his engine up to 10,000 RPM without oil or load
    > and it
    > > seized.
    > > He chiseled it apart and resurrected it and flew it for years until
    > > he mistakenly landed his airplane in the woods at night.
    > > In case you were wondering he was not hurt.
    > >
    > > Have you downloaded the shop manuals yet? I say this because I
    > > noticed you used the word "Babbitt". Real poured Babbitt bearings
    > have not
    > > been used for 75 years. They are now called bearing shells or
    > inserts.
    > > You press the inserts out with a tool that is just the right
    > diameter.
    > >
    > > Depending on how deep the wear marks are in the end housing
    > > you may not have to have them re-nitrides. It tells how to
    > > check them in the shop manuals. All you may need is a bit of
    > > re lapping.
    > >
    > > Paul Lamar ...No rotor no motor.
    >
    > Good news, indeed! I/we are greatly cheered. The guy in the pix is my
    > grandson David. He and his dad, Ken, are coming to NSF with me.
    >
    > We have the shop manual.
    >
    > I used "Babbitt" because that is the term Bruce Turpentine uses in
    > the DVD
    > on how to overhaul the 13B. I will no longer use the obsolete term. I
    > promise. :)
    >
    > BTW we will not arrive until Friday PM. I hope you will be around
    > Saturday
    > and Sunday. We leave Monday.
    > I definitely want a copy of your book.
    >
    > We are in the process of finding a tank big enough for the rotors.
    > As soon
    > as we get the rotors and other parts cleaned up I will send more pix.
    >
    > Doc Custer
    > Retired Software Engineer and sometime Audiologist
    >
    >
    > I'll be there on Saturday but every body splits Saturday
    > night or early Sunday morning. Better to get there on Thursday
    > or Friday. By Sunday morning a lot of airplanes are gone
    > and the locals come for the airshow.
    >
    > Paul Lamar ...No rotor no motor.
    >
    >
    >
    > I have a 20 gallon parts washer that is sitting around, Doc.
   Plenty deep
    > for the rotors. If you have a burning desire to fly/drive up to the
    > Springs you can borrow it for as long as you like. Maybe you
   could come
    > up in a weekend or two when I'm ready to fire up the engine again.
    >
    > Mark Sierpinski
    >
    > Mark Sierpinski

   I/we would love to come up and chat awhile. Just let me know when.
   The only
   weekend scheduled so far is NSF.

   What kind of parts washer?

   I have a small parts washer - the pump kind that you put kerosene or
   mineral
   spirits in and brush the part. What I really need, and am looking
   for, is a
   tank with crab cleaner or some other degrease chemical that won't
   eat AL or
   copper or whatever the inserts are made out of. We are currently
   using one
   of those one gallon cans of crab cleaner with a basket that you can soak
   small parts in. The rotors and housings won't fit in it, and whatever
   chemical cocktail is in it does a terrific job of getting the dirt,
   grease
   and carbon off; makes a long job much shorter. We would like to soak the
   rotors and housings.

   Grandson David found a 5 gal tank with chemicals for $90 on the net.
   We are
   going to see if we can get one locally. This might be big enough to
   fit the
   housings in. There is also a 16 gallon one for $407 that is mechanized,
   i.e., has a mechanical stirrer - but no chemicals. The chemicals are
   $17 -
   $20 per gallon. Ouch! Judging from the pix, the 16 gallon is the same
   diameter, just taller.

   Doc Custer
   Retired Software Engineer and sometime Audiologist


   You will need some heavy duty cleaner indeed to clean
   those rotors. They are usually a mess. In fact it takes
   longer to clean the rotors than over haul the engine :)

   Make sure you press those bearing shells out of the rotors
   first as they are affected by many solvents.

   Doc what is the status of the slide throttle parts?
   Are we close to being able to buy them?

   --
   Paul Lamar ...No rotor no motor.
   ---------------------------------------------

   Doc,

   An alternative for cleaning parts is to farm it out to an automotive
   machine shop or engine rebuilder.  If they aren't busy, the cost is
   fairly reasonable and they have washers that are made for this type
   of cleaning.

   Joel

That is what I would do. It is a messy job indeed :)

Paul Lamar

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