Mintor 140 Bearings

[Bob Pastorello]

Does anyone out there remember the mods we made to the pre-Hanno OS 61RF-ABC
pumpers?  If you all remember, that motor was NOTORIOUS for eating
bearings...rusting bearings...blowing retainers...balls getting peened into
multi-flat, dented metal chunks.....
    And somewhere, someone showed me a modified crankcase.  Some engine guru
had decided a groove was in order to allow more fuel (oil) into the front
face of the rear bearing race...the groove ran lengthwise from the upper
left corner of the carb intake window, straight back to the bearing face.
The idea was, more oil would be drawn into the front of the bearing.
    Two questions...
        One - does anyone remember this mod?  Did it work for you?  (mine
did improve bearing life)  and
        Two - has anyone tried this mod on the OS 1.40 ?  I'd think the same
principle should apply...

Any thoughts??

Bob Pastorello, Oklahoma
NSRCA 199, AMA 46373
rcaerobob at cox.net
www.rcaerobats.net


----- Original Message ----- 
From: <mdarr00 at comcast.net>
To: <discussion at nsrca.org>
Sent: Monday, August 04, 2003 12:29 PM
Subject: Re: Mintor 140 Bearings


>     Question #1 Yes, the O.S. 140 RX uses the same bearings as the Mintor
> 140.
>
>     Question #2  My personal experience has not been a corrosion issue in
> the O.S. engine.  In my opinion the bearing is not getting enough
> lubrication, which is causing the premature wear.  I also believe (and I
> could be wrong) that the O.S. 140 bearing is to small for its application.
> Which may be the reason that Mintor decided to use a rear bearing with two
> rows of balls in their 170 engine.
>
>     Question #3 I have used the Boca ceramic bearings in my O.S. and they
> did not last any longer than any of the other bearings.  Making be believe
> even more that it is not a corrosion issue.  More of a lack of
lubrication,
> and two small of a bearing for the job issue.  I believe the ceramic
bearing
> does not have any advantage in this application.  The ceramic bearings
still
> have chrome moly races, they just have ceramic balls.  Of course they are
> less likely to corrode, and will withstand higher temps, but I do not
> believe that is the issue in this case.
>
>     Now, I have not used Stainless bearings in my engine yet, but that is
> what I am going to use the next time they need replacement.  Word of
> caution, all stainless steel bearings can not be treated equal.  I have
> learned from other peoples experience that the best stainless steel
bearing
> is the O.S. FI factory bearing p/n 29430010.  That is the bearing I will
be
> using next, and I was told to leave the seals in the bearing to maintain
the
> factory grease in the bearing.
>
>     I am sure there are lots of other opinions of what is causing rear
> bearing failure in these engines, and that is what my suggestions are,
just
> my opinions.  I am not an expert on this subject, just thought I would
share
> some of my experiences with the group.
>
> Mike Darr
>
>
> ----- Original Message -----
> From: "VicenteRC" <vicenterc at comcast.net>
> To: "NSRCA" <discussion at nsrca.org>
> Sent: Monday, August 04, 2003 12:02 PM
> Subject: Mintor 140 Bearings
>
>
> >
> > I have three questions.
> >
> > 1. - Is the Mintor 140 bearings same size of the OS 140RX bearings?
> > 2. - The original bearings is these engines didn't last too long.  Yes,
> > I have both engines.  I estimated less than 50 flies each.  Clearly,
> > corrosion was the problem.  I already installed a new SS bearing on the
> > OS 140 RX.  I have a spare bearing that I hope I can use in the Mintor
> > 140.  The second question is: What is the approximate life of the SS
> > bearings?
> > 3. - Does it make sense to install ceramic bearings to improve the life?
> >
> > I switched this year to 2C and looks like I am doing something very
> > wrong.  I know that I am not following the Mintor instructions "run or
> > flush the engine with 0% nitro fuel is you don't use the engine for
> > more than one week"
> >
> > Thanks in advance,
> >
> > Vicente Bortone
> >
> >
> > =====================================
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> > #
> >
> >
>
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>

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