remedial engine question

[Henderson,Eric]

Boca has an SS bearing that works well in OS 1.40's. I change my OS engines to Stainless Steel (SS), as a matter of course, before I run any new OS engine these days.

The after run spray that Dean and Dave use seems to keep the original bearings clear of rust. It's the cage that rusts quickly and then forms "grinding paste" from the oil and rust powder deposits.

You can also get SS bearings from local bearing suppliers for around $15-18. Just take in the old one and by at least $25's worth and they will be happy.

In your case you might have sealed bearings. The rubber sometimes expands and rubs on the crankshaft.

The only time I have heard squeaking, however, was when a ring went soft from over heating. Best idea would be to take a look.

Eric.

-----Original Message-----
From: discussion-request at nsrca.org
[mailto:discussion-request at nsrca.org]On Behalf Of
patterndude at comcast.net
Sent: Monday, August 25, 2003 12:41 PM
To: discussion at nsrca.org
Subject: Re: remedial engine question



After a lot of experience I have concluded that bearing life is highly variable 
in a stressed environment.  30-200 flights are possible in the same 
airplane,engine on bearings purchased at the same time.  Factory OS bearings 
seem to be the worst quality, but there are some that will claim they last 
forecver.  I am just combining all the input to make a general statement. We 
can reduce the variability by providing a better operating env.  Our bearings 
exceed their tolerances at about 250 degrees, which is not that hot, so put a 
cooling scoop on the front or use cheeck cowls to something to keep air flowing 
over the bottom of the crank.  Use a low viscosity oil fuel like Magnum or 
Powermaster special fuel or heli.  Finally, set up fuel delivery to eliminate 
lean runs toward the end of the tank.  This greatly stresses the engine.  Some 
top fliers use bladder tank systems.  I just land with 1/3 tank.

--Lance

--
District 6 AVP
www.aeroslave.com
> Hi all,
> Have an RX with about thirty flights. The second day out I noticed a squeak 
> when turning the prop for restart. Thought something was hitting the 
> spinner, checked all that and it stopped. Yesterday heard it again and 
> noticed the bearings feel a little rough. Now hear is the weird part does 
> this only when hot. When cold feels fine and runs great. I plan on pulling 
> it apart tonight and changing bearings but pretty disappointed at the short 
> life.
> 
> Any one have similar experience?
> 
> Anthony
> 
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