REFLECTOR: Franklin seal leak

Mon Apr 18 11:53:44 CDT 2005

    Regarding Steve's observation about up and down end play in the crank:

When you try to feel for side to side movement you're working against all
the "muscle" of the engine (pistons, rods, etc.) and it's almost impossible
to detect play.  When you check up and down play (opposite the direction of
friction) you are often able to feel a little "click, click" if the play is
excessive.  That wouldn't necessarily mean you're out of specs unless you
mic the play though.  Air cooled engines get HOT so there must be enough
slack to allow for heat expansion or you'd freeze up and spin bearings.

    Another thought is the extent of the leak:

Is this just seepage, or a full blown leak?  Depending upon an engines
design, you may not ever be able to stop seepage.  Think about the attitude
the engine finds itself in during normal operation.  Sometimes it's
horizontal, sometimes nose up, sometimes nose down, and a million other
combinations as you fly around.  This can leave a fair amount of oil
"puddled" at the seals, so it's not any surprise that a little seepage will
occur.  On the other hand, if you're adding oil every time you land, that's
a leak :-)  Leaks you fix during maintenance.  Seepage, well that's like a
bad hair day.  --  It just happens, and it will happen every time you yell
"clear!"

Robin

===================

----- Original Message ----- 
From: "John Dibble" <aminetech at bluefrog.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Monday, April 18, 2005 11:00 AM
Subject: Re: REFLECTOR: Franklin seal leak

> Thanks Steve.  That's an interesting point about oil temp.  Mine normally
run 92-98 C
> (198-208F).  When I replaced the seal there was a lot of dark brown
deposit on the
> shaft and I wonder if this abraded the seal and made it start leaking.  I
assume the
> deposit came from degradation of the oil, perhaps due to a high temp.
What are your
> oil temps (before and now)?
> When I bought my Velocity it had 205 hours and the seal was not leaking.
I flew it for
> about 100 hours before the seal began leaking.  I wonder if one's
operating habits
> (MAP, rpm, and amount of leaning) have any impact.
> Do you balance the prop?
>
> Steve wrote:
>
> > My Franklin has only 65 hrs on it. I have already replaced the
> > crankshaft seal due to it leaking oil. It still leaked with a new seal.
> > I have also been working on getting my oil temp down  ... with some
> > success. Since the oil temps came down, the oil leaking from the
> > crankshaft seal stopped leaking., so maybe its a temperature related
> > thing ??
> >
> > Pure coincidence, I happened to check for any play in the crankshaft
> > last week and was surprised to find a little play up and down but none
> > from side to side. I am still pondering this when up pops your e-mail.
> > Sounds like you have some experience or knowledge of this.
> >
> > I would appreciate hearing what you know. Is this a known Franklin issue
> > ? How much of a concern (if any) does it represent ?
> >
> > Steve
> >
> > Robin Ream wrote:
> >
> > >Just out of curiosity, can you feel any up and down play in the output
end
> > >of the crank shaft, and did you dynamically balance the prop?
> > >
> > >Robin
> > >==========================
> > >
> > >----- Original Message -----
> > >From: "John Dibble" <aminetech at bluefrog.com>
> > >To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> > >Sent: Sunday, April 17, 2005 6:21 PM
> > >Subject: REFLECTOR: Franklin seal leak
> > >
> > >
> > >
> > >
> > >>I have a 220 hp Franklin/IVO prop with 370 hours.  Recently I replaced
a
> > >>
> > >>
> > >leaking
> > >
> > >
> > >>crankshaft seal at the prop end.  After 28 hours, the new seal has
started
> > >>
> > >>
> > >leaking.
> > >
> > >
> > >>Any ideas what is causing this?  I cruise between 2400-2500 rpm.  What
rpm
> > >>
> > >>
> > >do others
> > >
> > >
> > >>cruise at?  Thanks, John
> > >>
> > >>
> > >>
> > >>_______________________________________________
> > >>To change your email address, visit
> > >>
> > >>
> > >http://www.tvbf.org/mailman/listinfo/reflector
> > >
> > >
> > >>Visit the gallery!  www.tvbf.org/gallery
> > >>user:pw = tvbf:jamaicangoose
> > >>Check new archives: www.tvbf.org/pipermail
> > >>Check old archives:
http://www.tvbf.org/archives/velocity/maillist.html
> > >>
> > >>
> > >>
> > >
> > >
> > >_______________________________________________
> > >To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
> > >
> > >Visit the gallery!  www.tvbf.org/gallery
> > >user:pw = tvbf:jamaicangoose
> > >Check new archives: www.tvbf.org/pipermail
> > >Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> > >
> > >
> > >
> > >
> >
> > _______________________________________________
> > To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
> >
> > Visit the gallery!  www.tvbf.org/gallery
> > user:pw = tvbf:jamaicangoose
> > Check new archives: www.tvbf.org/pipermail
> > Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
>
> _______________________________________________
> To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>