[SEL] Babbitt bearings poured on the Alamo.

[Curt]

Arnie Fero wrote:

>Hi Curt,
>
>VERY impressive piece of work!!  I really like the fixture design for
>positioning the dummy shaft.  I have a couple of questions.
>
>You're pre-heating to 550 deg.F and you're using the upper cap with the
>new bearing in place as a part of the fixturing.  What temperature does
>your babbit melt at?  I would have thought it melted around 500 deg.F
>(obviously not).
>  
>
Arnie,
The uppers were poured, allowed to cool, and then removed. They were not 
used to do any aligning for the lowers.  The fixture held the dummy 
shaft in suspension in the correct location for pouring both the uppers 
and lowers in separate pours.

>I didn't see the classic X-groove to help distribute grease across the
>bearing surface.
>  
>
I didn't cut the grooves yet (if I decide to use grease I will) because 
the flywheels will have to come out again to clean the built in fuel 
tank in the base.
I am a proponent of oil as this constantly washes abrasive material out 
of bearings and I will likely install nice brass drip oilers on the 
engine. The 45° chamfers on the leading side (hard to see in the next to 
the last picture) are sufficient to distribute oil across the face of 
the bearing. There will simply be a straight groove across the top of 
the bearing in the cap that is about a 1/8 wide x a 1/8 deep to 
ditribute oil across the width of the bearing. This will stop about 1/2" 
from the ends.

>You mention a 45-deg. bevel to "build the pressure wedge for the
>lubricant film."  I think of hydrodynamic oil pressure effects as a
>characteristic of much higher rotation speeds; like >1000 RPM,
>not ~100 RPM.
>  
>
Hydrodynamic lubrication is a function of velocity and viscosity. But it 
will occur at almost any speed with a viscous enough lubricant. 
Interesting enough I put the crankshaft and flywheels in dry. Before 
rolling I filled the pressure wedge groove with 40wt. oil. A half turn 
of the shaft and the shaft was whetted. As the wheels are rotated you 
can see the classic pressure wedge of oil rolling.  But the key is 
constant oil and high viscosity oil.
Most of our forging machines here at work are 1 stroke a second (60 
rpm). This pressure wedge via the 45 ° chamfer is the sole means of 
lubricating the bearings. Years ago I switched the lubricant from the 
factory suggested 220 to 320. This has greatly reduced wear to bearings.

>Somewhere on the net a SEL FAQ is maintained.  I sure hope that SOMEONE is
>capturing well documented work like this for the FAQ.
>
>See ya,  Arnie
>
>Arnie Fero
>Pittsburgh, PA
>fero_ah at city-net.com
>
>On Mon, 1 May 2006, Curt wrote:
>
>  
>
>>Folks this was a banner weekend! Accomplished a significant milestone in
>>the restoration of the Alamo engine by successfully pouring both the
>>lower and upper mains on this engine. I had done lowers before, but was
>>apprehensive about the uppers. As it turned out they were easier than
>>the lowers. Missy and I picture documented this as best we could and
>>I've put it on the website. Maybe it will be useful to someone when
>>pouring theirs.
>>Here is the link:
>>http://www.oldengine.org/members/holland/images/AlamoBabbittPouring/Thumbnails.html
>>    
>>
>
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>  
>