Babbitt Metal is a Soft Metal for the Main Bearings in an Engine

"Babbitt, also called Babbitt metal or bearing metal, is any of several alloys used for the bearing surface in a plain bearing."

Wikipedia

One of my competitors likes to mention that he uses Henry Ford's original Babbitt formula.  While there is nothing wrong with that remember that Henry Ford was not the only manufacturer of cars back then nor was his the only Babbitt formula.  The policy at Aldrich is the right Babbitt for the job.  If you specify a particular Babbitt formula we'll use that.  If no specification is made I'll typically use NO.2 Genuine (87% Tin, 7% Antimony, 3.5% Copper and .5% Lead).  I've had great success with this particular formula but if something else is called for I'll use whatever is best for that particular job.  Bottom line on all this Babbitt stuff - it will make a difference!

On a recent job I noticed the rods had excessive clearance on the thrust faces and this was a "rebuilt" engine.  I looked a little closer at the babbitt on the rods and discovered that they were rebabbitted with lead based babbitt!   Wow!!!  LEAD based babbitt is used and still sold to rebuild wood shop machinery like table saws, band saws, planers, etc.  LEAD BASED babbitt CANNOT WITHSTAND what is called Reciprocating Mass. In other words, up and down, round and round motion and vibration.  Folks working on the major FORD models A , B, V-8 and T (frequently out of habit or for cost) use lead based babbitt.  What can I say?  Old habits can be hard to break.  It can take a little extra effort to switch to genuine tin based babbitt like I use.  The tin based babbitt generally costs a little more also, it should, better quality generally does.  When suppliers buy lead based babbitt rods, they resell them to guys to use in their cars.  Within a year those rods have "pounded out" and the clearances need to be readjusted.

In short they're so cheap they're expensive due to constant readjusting of the shims, replacing oil pan gaskets and time spent laying under a car that you should be driving.  The engine I took apart was "rebuilt" to sell the truck.  It's cylinders were bored out, new pistons/rings were installed, the valves were poorly reground, other sub-standard things were done and the rods were those lead based ones.  This engines off of “life support” for now but I'm still working on it and can only wonder about the crank and mains.