Steam Engine Restoration Part 12 - Modifying And Finishing the Connecting Rod Bearing (Video Post)

When I pulled apart and sandblasted the connecting rod during disassembly, I noticed something strange about the lower rod bearing. The bearing boss had been machined to exactly the diameter of the crankshaft, and the oil passages had never been drilled out. There was no room to pour babbit between the rod and the pin, and no way to lubricate it.

It appeared that someone had simply forgotten to finish machining the rod bearing, which may explain the relative lack of wear to the rest of the engine. Most likely, the engine had never run correctly or for long periods of time, which would also explain its partial disassembly and abandonment. The only way to properly complete the engine was to finish the work and rebuild the bearing.

Boring the lower rod bearing to the correct diameter

Finishing the Boring

Drilling out the bearing grease passage

Tapping the grease passage for a zerk fitting

Drilling shallow holes into the sides of the lower rod. Babbitt will flow into these holes and lock the bearing material in place.

Lower Rod Bearing Cap completed

Adding retainer holes to the upper portion

After 100 years, this part has finally been machined to spec.

Adding grease fittings to the valve eccentric parts

The completed and painted valve eccentric assembly

Prepping for Babbitt

This rod is machined to the same diameter of the crank pin. The side spacers hold the pin in the correct location in the lower rod.

Mold placed into the upper rod bearing.

Adding clay and metal forms to the edges

Forming the spigot.

Ready to pour

The final result. Unfortunately, the Babbitt cooled before it filled the entire space, but this should be more than enough to run it in demonstrations.

Adding the bearing shims