Mintor 140 Bearings

[Verne Koester]

Bob,
Interestingly enough, my RX has the groove you describe going forward toward
the front bearing (which is shielded anyway) but nothing rearward. I
considered that as a last option if nothing else worked, but haven't needed
to as yet.

Since they already have a shielded bearing in the front, I have to assume
that groove is there to lube the crank journal in the case between the carb
opening and the front bearing. If that's the case, then why no groove to
lube the journal between the carb opening and the rear bearing? Friction
equals heat, right? Maybe they're relying on the heated aluminum case
expanding enough to allow oil in there but then there'd be no reason for the
forward groove.

Verne


----- Original Message -----
From: "Bob Pastorello" <rcaerobob at cox.net>
To: <discussion at nsrca.org>
Sent: Monday, August 04, 2003 10:35 PM
Subject: Re: Mintor 140 Bearings


> 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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