Bearings Replacement

Bearings Replacement

Post by Normen Strobe » Wed, 30 Jul 2003 22:39:12



I have an OS 46FX which internal bearings are completely rusted.  The ones
in front by the prop seem fine.  My question is how hard is it pull the
bearings out and put new ones in?  Boca Bearings sells several different
kinds of bearings, which one is the best for the money.  I don't think it's
worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody know if
one of the hobby mags ran a Engine Clinic article on the OS 46FX?

Thanks

--
Normen Strobel

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Bearings Replacement

Post by Dr1Driv » Wed, 30 Jul 2003 23:25:17


Quote:
>My question is how hard is it pull the
>bearings out and put new ones in?

Easy.  First, completely disassemble the engine. When you pull the crankshaft,
the rear bearing may come with it.  If not, follow this procedure:
1.  Heat the engine in a 200 degree F oven for about 20 minutes.
2.  Using a mitt, smack the rear of the crankcase sharply against a block of
wood.
3.  The rear bearing should fall out.

To reinstall:
1.  Slide the rear bearing on the crankshaft.
2.  Use a block of wood to tap the bearing into place.
3.  Reassemble the engine.

In both cases, the front bearing can be tapped out using a wooden dowel, and
tapped back in using a block of wood.

If you have never completely opened an engine and replaced bearings, I suggest
you watch it being done before you do one.
Dr.1 Driver
"There's a Hun in the sun!"

 
 
 

Bearings Replacement

Post by Normen Strobe » Wed, 30 Jul 2003 23:55:59


Thanks, does the engine still need to be warm to put the new bearing in?

--
Normen Strobel


Quote:
> >My question is how hard is it pull the
> >bearings out and put new ones in?

> Easy.  First, completely disassemble the engine. When you pull the
crankshaft,
> the rear bearing may come with it.  If not, follow this procedure:
> 1.  Heat the engine in a 200 degree F oven for about 20 minutes.
> 2.  Using a mitt, smack the rear of the crankcase sharply against a block
of
> wood.
> 3.  The rear bearing should fall out.

> To reinstall:
> 1.  Slide the rear bearing on the crankshaft.
> 2.  Use a block of wood to tap the bearing into place.
> 3.  Reassemble the engine.

> In both cases, the front bearing can be tapped out using a wooden dowel,
and
> tapped back in using a block of wood.

> If you have never completely opened an engine and replaced bearings, I
suggest
> you watch it being done before you do one.
> Dr.1 Driver
> "There's a Hun in the sun!"

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Bearings Replacement

Post by emc.. » Thu, 31 Jul 2003 00:30:08


If you do replace the front bearing, I would get a sealed one.

A sealed front bearing stops fuel and air leaks. Some engines come
from the factory with a sealed front bearing, some do not.

I purchased the standard rear bearing when the one in my Saito .65
needed replacing. The new bearing has performed excellent for the past
3 or 4 years.

A more expensive bearing is probably not needed.

Heat the engine case as Dr1Driver posted.

On Tue, 29 Jul 2003 09:39:12 -0400, "Normen Strobel"

Quote:

>I have an OS 46FX which internal bearings are completely rusted.  The ones
>in front by the prop seem fine.  My question is how hard is it pull the
>bearings out and put new ones in?  Boca Bearings sells several different
>kinds of bearings, which one is the best for the money.  I don't think it's
>worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody know if
>one of the hobby mags ran a Engine Clinic article on the OS 46FX?

>Thanks

 
 
 

Bearings Replacement

Post by Paul McIntos » Thu, 31 Jul 2003 00:45:33


Look at my web site under Bearing FAQs for a generic, but fiarly complete
bearing replacement method.

I also have ceramic bearings in stock for the OS 40-46FX for $17.97 plus
shipping.

--
Paul McIntosh
Desert Sky Model Aviation
http://fly.mcintoshcentral.com

Quote:
> I have an OS 46FX which internal bearings are completely rusted.  The ones
> in front by the prop seem fine.  My question is how hard is it pull the
> bearings out and put new ones in?  Boca Bearings sells several different
> kinds of bearings, which one is the best for the money.  I don't think
it's
> worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody know
if
> one of the hobby mags ran a Engine Clinic article on the OS 46FX?

> Thanks

> --
> Normen Strobel

> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----

 
 
 

Bearings Replacement

Post by Dr1Driv » Thu, 31 Jul 2003 03:41:53


Quote:
>A sealed front bearing stops fuel and air leaks.

Sorry, not correct.  The fit between the crankshaft and crankcase journal in
the area of the intake (and possibly a spiral oil groove on the crankshaft)
creates the seal. If the bearing was sealed (and they are sealed on both
sides), no lubrication could get inside the race.

Dr.1 Driver
"There's a Hun in the sun!"

 
 
 

Bearings Replacement

Post by Bill Fulme » Thu, 31 Jul 2003 04:04:10


I've use many bearings with seals and/or shields in RC engines.  No biggie
to remove the inner seal/shield (or, BOTH, in the case of a rear brg.) to
allow race lubrication..  A small amount of oil may escape the nose, but
that's no problem, either...  It's what they do.........

Bill


Quote:
> >A sealed front bearing stops fuel and air leaks.

> Sorry, not correct.  The fit between the crankshaft and crankcase journal
in
> the area of the intake (and possibly a spiral oil groove on the
crankshaft)
> creates the seal. If the bearing was sealed (and they are sealed on both
> sides), no lubrication could get inside the race.

> Dr.1 Driver
> "There's a Hun in the sun!"

 
 
 

Bearings Replacement

Post by Mathew Kirs » Thu, 31 Jul 2003 05:02:55


Quote:

> Thanks, does the engine still need to be warm to put the new bearing in?

Yes. The bearings are a press fit, and since most of us don't have
presses, having the case hot is the next best thing.

Make sure you use the crankshaft to install and align the bearings.
It's not pretty if you just try to drop them in.

 
 
 

Bearings Replacement

Post by Paul McIntos » Thu, 31 Jul 2003 05:53:07


DR,

Sealed bearings are lubed at the factory with a permanent grease.  They do
not rely on the two stroke fuel for lubricants.  Several engines have sealed
bearings as standard, such as most YS engines and other engines using
crankcase pressure fed pumps.

For engines with significan front leakage (enough to cause tuning problems),
a sealed bearing may solve the problem.

--
Paul McIntosh
Desert Sky Model Aviation
http://fly.mcintoshcentral.com

Quote:
> >A sealed front bearing stops fuel and air leaks.

> Sorry, not correct.  The fit between the crankshaft and crankcase journal
in
> the area of the intake (and possibly a spiral oil groove on the
crankshaft)
> creates the seal. If the bearing was sealed (and they are sealed on both
> sides), no lubrication could get inside the race.

> Dr.1 Driver
> "There's a Hun in the sun!"

 
 
 

Bearings Replacement

Post by Dr1Driv » Thu, 31 Jul 2003 10:19:10


Quote:
>Sealed bearings are lubed at the factory with a permanent grease.

Interesting.  I admit my expertise is with Oilite-type sleeves.  I was the
engineer for 8 years at a plant where they made them.  I still maintain that
the crank/case fit is what keeps down leakage, though.
Dr.1 Driver
"There's a Hun in the sun!"
 
 
 

Bearings Replacement

Post by Bruce_ » Fri, 01 Aug 2003 09:38:40


I just went thru this process. I bought new bearings from Boca. My
original front bearing (Saito 100) had completly self destructed. all
that was left was the outer race (ceramic bearings do not like being
run into the  ground)!! Anyhow, the way i done the reinstall was to
put the new bearings and crankshaft in the freezer over night. then i
put the crankcase in toaster over at 350 degrees for ohhhhh ... maybe
15 minutes, or till the over thermostat shut it off for temp. then,
using a pair of heavy gloves, i put the bearings in. the front bearing
"fell" in place. then put the rear bearing on the crankshaft and put
it into the case and everything fell into place. no hammering,
tapping, pounding or any force at all was required.

  Not saying this is the best way, or the only way, only that it
worked for me and is most easy to do.

Bruce_C.

Quote:

> I have an OS 46FX which internal bearings are completely rusted.  The ones
> in front by the prop seem fine.  My question is how hard is it pull the
> bearings out and put new ones in?  Boca Bearings sells several different
> kinds of bearings, which one is the best for the money.  I don't think it's
> worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody know if
> one of the hobby mags ran a Engine Clinic article on the OS 46FX?

> Thanks

> --
> Normen Strobel

> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----

 
 
 

Bearings Replacement

Post by Pé Reiver » Sat, 02 Aug 2003 04:00:45


It sure is the best way, though you should skip the freezer part. It
attracts moisture to the cold surfaces, which you can do without when
assembling parts.

--
Rgds,
P
From Arcen, South-East in the Netherlands

mvvs-nl.com
http://mvvs-nl.com/
www.prme.nl


Quote:
> I just went thru this process. I bought new bearings from Boca. My
> original front bearing (Saito 100) had completly self destructed. all
> that was left was the outer race (ceramic bearings do not like being
> run into the  ground)!! Anyhow, the way i done the reinstall was to
> put the new bearings and crankshaft in the freezer over night. then i
> put the crankcase in toaster over at 350 degrees for ohhhhh ... maybe
> 15 minutes, or till the over thermostat shut it off for temp. then,
> using a pair of heavy gloves, i put the bearings in. the front bearing
> "fell" in place. then put the rear bearing on the crankshaft and put
> it into the case and everything fell into place. no hammering,
> tapping, pounding or any force at all was required.

>   Not saying this is the best way, or the only way, only that it
> worked for me and is most easy to do.

> Bruce_C.




- Show quoted text -

Quote:
> > I have an OS 46FX which internal bearings are completely rusted.  The
ones
> > in front by the prop seem fine.  My question is how hard is it pull the
> > bearings out and put new ones in?  Boca Bearings sells several different
> > kinds of bearings, which one is the best for the money.  I don't think
it's
> > worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody
know if
> > one of the hobby mags ran a Engine Clinic article on the OS 46FX?

> > Thanks

> > --
> > Normen Strobel

> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> > http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> > -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----

 
 
 

Bearings Replacement

Post by Paul McIntos » Mon, 04 Aug 2003 04:16:54


In most cases, a good fit is required.  However, if the fit isn't so good, a
sealed bearing may work.

All of my sealed bearings come with Mobil channeling grease installed.  This
grease will outlast the engine.

--
Paul McIntosh
Desert Sky Model Aviation
http://fly.mcintoshcentral.com

Quote:
> >Sealed bearings are lubed at the factory with a permanent grease.

> Interesting.  I admit my expertise is with Oilite-type sleeves.  I was the
> engineer for 8 years at a plant where they made them.  I still maintain
that
> the crank/case fit is what keeps down leakage, though.
> Dr.1 Driver
> "There's a Hun in the sun!"

 
 
 

Bearings Replacement

Post by Paul McIntos » Mon, 04 Aug 2003 04:17:58


Look at my web site under FAQs and you will see essentially the same
process.  I don't think it is necessary to freeze the bearings or heat the
crankcase that hot, though.

--
Paul McIntosh
Desert Sky Model Aviation
http://fly.mcintoshcentral.com

Quote:
> I just went thru this process. I bought new bearings from Boca. My
> original front bearing (Saito 100) had completly self destructed. all
> that was left was the outer race (ceramic bearings do not like being
> run into the  ground)!! Anyhow, the way i done the reinstall was to
> put the new bearings and crankshaft in the freezer over night. then i
> put the crankcase in toaster over at 350 degrees for ohhhhh ... maybe
> 15 minutes, or till the over thermostat shut it off for temp. then,
> using a pair of heavy gloves, i put the bearings in. the front bearing
> "fell" in place. then put the rear bearing on the crankshaft and put
> it into the case and everything fell into place. no hammering,
> tapping, pounding or any force at all was required.

>   Not saying this is the best way, or the only way, only that it
> worked for me and is most easy to do.

> Bruce_C.




- Show quoted text -

Quote:
> > I have an OS 46FX which internal bearings are completely rusted.  The
ones
> > in front by the prop seem fine.  My question is how hard is it pull the
> > bearings out and put new ones in?  Boca Bearings sells several different
> > kinds of bearings, which one is the best for the money.  I don't think
it's
> > worth the $75 to put Ceramic Bearing in a $100 engine?  Does anybody
know if
> > one of the hobby mags ran a Engine Clinic article on the OS 46FX?

> > Thanks

> > --
> > Normen Strobel

> > -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> > http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> > -----==  Over 80,000 Newsgroups - 16 Different Servers! =-----

 
 
 

Bearings Replacement

Post by John Hawkin » Mon, 04 Aug 2003 06:16:16


        Referring to the 350oF, I was just checking the Jett Engines
site and they give the max as 325o as the heat treatment of the case
begins to be affected above that temp.

On Sat, 2 Aug 2003 19:17:58 +0000 (UTC), "Paul McIntosh"

Quote:

>Look at my web site under FAQs and you will see essentially the same
>process.  I don't think it is necessary to freeze the bearings or heat the
>crankcase that hot, though.