[SEL] Pitted shaft & Babbitt bearings

[Arnie Fero]

Hi Andy,

As an alternative to JBWeld, McMaster-Carr lists a couple of high
temperature epoxy putties.  One for aluminum rated to 1400 deg.F and one
for cast iron, steel, and stainless rated to 2000 deg.F.  Under $30 for 8
oz.  Look for 7356A33 (or 7356A32 for the aluminum).
http://www.mcmaster.com/

They also carry the high temperature titanium Devcon rated to 350 deg.F.
That's a bit higher at $65 for a pound.

Realistically, you could probably use the JBWeld also.  The worst that
could happen is that some of it burns out leaving a lesser pit than you
have now.  You'd still need to scrape that as Larry describes, but it
would probably be less scraping than if you left the pits unfilled.

What diameter is the shaft?  If it's beefy, the heat sink effect of the
shaft would probably conduct enough heat away that the JBWeld wouldn't be
badly damaged.

Or just drop $30 and go for the high temperature stuff.  8-))

See ya,  Arnie

Arnie Fero
Pittsburgh, PA
fero_ah at city-net.com

On Tue, 19 Apr 2005, Larry Sain wrote:

> I'm pretty much an expert, having poured a grand total of one bearing, so
> take my experience for what it's worth.  The con rod bearing on my 20 HP
> Bessemer was in pieces and the crank pin had a pretty bad crater in it as
> well as some smaller pits.  Upon the advice of some true oil field engine
> experts, I poured the bearing, scraped it, cut oil grooves and left the pits
> alone, other than cleaning them.  The engine runs flawlessly under no load
> and a max of 80-90 rpm.  Since the crank pin is 3 and 3/4 inches in
> diameter, even a pretty nasty pit has little effect on the structural
> integrity or so I'm told.  You could always pour the bearing and Then fill
> the pits with JB, thus avoiding the heat of the pour.  You'll want to scrape
> the bearings anyway so the buildup from the pitted areas will be gone.  Cut
> your oil grooves and fire it up.  Good luck.
>
> ----- Original Message -----
> From: "Andy Glines" <andyglines at hotmail.com>
>
> > I have an issue with one of the shafts that needs new bearings.  The
> > shaft is badly pitted so it
> > needs repair before pouring a new bearing.  My initial thought was to fill
> > the pits with JBweld.  The JB will work fine in operation but I'm worried
> > about it holding up the heat of pouring the bearing.