Another bearing question....

[Wayne Galligan]

Georgie,

The key word there is "possible bad bearing"  I can only assume that it may
have something to do with the vibration the bearing makes at that particular
rpm or something. I really dont know.  All I know is that when it starts
happening on my OS I was having a bearing problem that I confirmed by
wiggling the prop at the tips and had some end play.  It did not have the
rough feeling when turning spinner. Replaced the bearing and it ran perfect.
Didn't mean to confuse...   Perhaps there is a more technical explanation
for it.  That's just my experience with this particular engine.

Wayne Galligan
----- Original Message ----- 
From: "george kennie" <geobet at gis.net>
To: <discussion at nsrca.org>
Sent: Thursday, October 23, 2003 1:03 PM
Subject: Re: Another bearing question....


> Boy, that blows me away! Somebody that's an engine guru please explain why
a
> faulty bearing causes the mid-range loading-up problem.
> I have a 60 size engine that is a few years old that will turn a 12x7 prop
over
> 12K rpm and idles below 2000, and transitions beautifully, but if I run it
up to
> full power and let it run for about 30 seconds, at which time it sounds
awesome,
> and then reduce the throttle to 9000 rpm, it will run good for about 5
seconds
> and then start to load up and will quit, while at this setting after about
15
> seconds.
> It just happens to be sitting on my benchtop with a prop on it and I just
went
> in and turned it over. The bearing feels smooth, there is no slop in the
prop
> tips and there is absolutely no end play.
> Maybe I should keep the bearing and order the rest of the parts to build
up a
> new engine.
> Hmmmm, .........still confused.
> Georgie
>
> Wayne Galligan wrote:
>
> > My OS will do the loading up in the midrange and die thing.  It has
happened
> > on the last two bearings thus giving me the warning.  Then of course I
could
> > verify the end play at the tips of the prop. Funny thing was I couldn't
feel
> > any roughness.  But after a fresh bearing it ran fine.
> >
> > Wayne
> >
> > ----- Original Message -----
> > From: "White, Chris" <chris at ssd.fsi.com>
> > To: <discussion at nsrca.org>
> > Sent: Wednesday, October 22, 2003 2:55 PM
> > Subject: RE: Another bearing question....
> >
> > > Thanks Wayne.... The first 2 I would expect, the 3rd is new to me, and
the
> > > fourth....well that kind of says why we care....:)
> > > Chris
> > >
> > > -----Original Message-----
> > > From: Wayne Galligan [mailto:wgalligan at goodsonacura.com]
> > > Sent: Wednesday, October 22, 2003 2:47 PM
> > > To: discussion at nsrca.org
> > > Subject: Re: Another bearing question....
> > >
> > >
> > > If you rock the spinner back and forth and it is not smooth or you
feel
> > > roughness.....bad bearing.   If you grab the prop by the tips and
wiggle
> > it
> > > back and forth and there is end play.... bad bearing.  If you
experience
> > > sudden changes in the midrange like loading up and engine quits on
spool
> > up
> > > and plug is OK....possible bad bearing.
> > >
> > > Or if you see metal filings coming out the exhaust....... TOO LATE bad
> > > bearing and engine.
> > >
> > > Wayne G.
> > > ----- Original Message -----
> > > From: "White, Chris" <chris at ssd.fsi.com>
> > > To: <discussion at nsrca.org>
> > > Sent: Wednesday, October 22, 2003 2:32 PM
> > > Subject: Another bearing question....
> > >
> > >
> > > > Hi!
> > > > I hear of guys getting anywhere from 35 to 400 flights on bearings:
> > > >
> > > > What are the first signs of bearing problems. Since starting
> > Intermediate
> > > > practice in July, I have just got into flying the same
airplane/engine
> > > > regularly enough to wear on an engine and tell the difference in
> > > > performance.  I have 97 flights on a Zen/Webra 145AAR combination. I
use
> > > > Cool Power 15% and after run oil religiously.  I have a  tach which
> > varies
> > > > so much with light emissions that I deem it as unreliable.  So what
do
> > you
> > > > look for?
> > > >
> > > >
> > > > Thanks, Chris
> > > >
> > > > -----Original Message-----
> > > > From: gene.maurice at comcast.net [mailto:gene.maurice at comcast.net]
> > > > Sent: Wednesday, October 22, 2003 2:07 PM
> > > > To: discussion at nsrca.org
> > > > Subject: RE: bearing question
> > > >
> > > >
> > > > Try WWW.AFCBEARING.COM. Great prices and so far a good product. They
> > carry
> > > > all of the standard sizes, but some of them have to be shipped from
> > Japan.
> > > I
> > > > am using their sealed SS bearing in my OS 160 with the seals and
grease
> > > > intact. 120 flights (+-) without a problem. And I am using crank
> > pressure
> > > to
> > > > power a Perry pump. This is after going through 2 sets of carbon
steel
> > > > bearings after less than 35 flights each.
> > > >
> > > > --
> > > > Gene Maurice
> > > > AMA 3408 NSRCA 877
> > > > Plano, TX
> > > > gene.maurice at comcast.net
> > > >
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