Pouring Babbitt Bearings

Antique gas engine repair


| September/October 2002



Plumber's stove

Plumber's stove for melting babbitt.

The wear and tear an oil field engine experiences as one of our toys is probably pretty mild compared to the abuse it experienced in its working life in the field. We pamper our engines, making sure they are well oiled and in good working order. Unfortunately, these engines don't always come to us in good shape forcing us into antique gas engine repair. I have seen many old engines knocking from worn out bearings, and I've even seen an engine using shims from an old cereal box.

Some engines wouldn't even get new bearings poured when they wore. I have seen several that were put back into service with a piece of leather belt wrapped around the shaft and plenty of oil to remedy the offending bearing. Sometimes the worn shell on the bottom would be swapped with the other half in the bearing cap. As collectors, however, our labor of love forces us to properly repair these problems, which often means pouring babbitt bearings.

Babbitt
Babbitt is a mixture of lead and tin, and for obvious reasons much softer than your crankshaft. It is normally 80-1/4 percent lead, 14-3/4 percent antimony and 5 percent tin. This material will serve as a durable bearing for wear surfaces for years if oiled well and not run hot. Babbitt can be purchased from many places, but you can also salvage what you melt out of your old bearing or from other shells when re-babbitting an engine. When you melt out old Babbitt all the nasty stuff (such as dirt, old oil and grease) burns off or rises to the top of the molten pool. Using an old plumbers soldering iron (or other piece of flat steel) you can rake the contaminants off the top of the molten pool. Small quantities of wax from a toilet bowl ring can be dropped in to assist the separation of the babbitt from any dirt. A good trick when heating babbitt is using a piece of Cedar wood to determine if the babbitt's hot enough to pour. Dip the wood into the molten pool, and if the wood burns with a flame the babbitt's hot enough to pour. If the wood's only scorched it needs more heat. I am told this is around 650 degrees F.

Before I go further on this subject, I must stress the need for absolute care, as hot babbitt can cause severe burns. Common sense and rigid safety practices should be observed when handling molten metals. Always wear protective clothing and gear, and remember that water is a no-no around molten babbitt: It can cause it to explode. Please, practice safety first.

Getting Ready
The first thing you'll need is some way to melt the babbitt. I use an old white gas plumber's stove, but a rosebud torch will work. You will need a torch to melt out remnants of the old bearing and to burn off the remainder of the old oil and grease. An acetylene torch and an assortment of ladles and pots for melting the babbitt will be necessary - most importantly you'll need a good long-handled ladle with a notched spout for pouring.

You'll also need a commercial version of damming clay, which is usually available from industrial supply catalogs, and of course all the necessary equipment for lifting and blocking up the flywheels and crankshaft. Keep some flat pieces of wood and pieces of leather for shim spacers handy, and possibly a toilet bowl ring or beeswax and a cedar shingle.