Saturday, October 25, 2014

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

Monday, October 6, 2014

Steam Engine Restoration Part 11 - Finishing the Crankshaft Bearings (Video Post)

I got a bit ahead of myself with the successful test run, so I want to backtrack and post the rest of the Babbitting process.

After pouring the bottom of the main crank bearings, I scraped, finished, and reinstalled them, and then laid the crankshaft in place. Next, shim stock was placed on the joining surface, clay was packed around the edges of the bearing block, and the top cap of the bearing block was bolted in place.

The fresh babbitt had to be poured through the bearing port, so I installed a sacrificial pipe fitting to protect the threads of the hole.

Next, I packed clay around the fitting to form a cup that would guide the babbitt into the bearing block.

Unfortunately, the babbitt hardened a little too quickly this time, so the right bearing block cap didn't fill up all the way. However, since this engine will be run at a reduced capacity, this should be enough material to support the crankshaft.

Saturday, October 4, 2014

CL450 Racer - Syncing The Carburetors (Homemade Vacuum Gauge)

This is a quick video post to show the custom Carb Sync Vacuum Gauge set that I built. Most of the available sets use regular vacuum gauges and an adjustment valve to smooth out the engine ignition pulses. Without this valve, the needles would rapidly jump in time with the engine vacuum from the intake stroke, so it is difficult to take a reading. 

Instead of this design, I built a gauge set that uses Glycerin-filled gauges. Glycerin is a thick liquid and fills the entire gauge, which resists the movement of the needle and causes it to move slowly. This action dampens the needle's response to the vacuum pulses, which smooths out and stabilizes the reading.