Story of Lilly/Struthers Wells Halfbreed Oil Field Engine


Posted: July 29th, 2022 by

Before I get into the story of this engine, I thought I would explain what a halfbreed oil field engine is. The early oil industry used steam engines for various jobs in the oil fields during the mid to late 1800’s. It was in the early 1900’s when companies began to convert steam engines into gas engines. This proved to be less time consuming to maintain. The other advantage was that gas engines could be run off well gas (a byproduct of the well) which was free and already at the engine location.

The term halfbreed engine refers to the gas cylinder and associated parts as one half, the steam engine bed (crankshaft, crosshead, engine base and flywheel) as the other half. This was a very popular conversion and many different manufacturers started to produce parts to build gas engine conversions. Many of the companies producing the conversions were in the Bradford, PA area because the oil field industry was booming there at that time.

The engine featured here started out as a Struthers Wells steam engine and was converted with a Lilly cylinder, head, connecting rod, and intake valve. The Lilly Engine Company was located in Rixford, PA, McKean County, near Bradford.

This engine was originally used in the Dallas, PA area near Bradford, on the Devlin Oil Lease. I purchased the engine from Dennis Griesbaum around the year 2012. Denny is an engine collector and oil field mechanic who works on anything oil field related. The engine was in poor condition and was also missing some parts. When purchased, it was disassembled and sand blasted prior to any machine work. The piston was stuck in the cylinder but the bore condition was not too bad after removing the piston and honing the bore. The crankshaft was turned down by Jim Cook. He also machined a newly cast connecting rod bearing cast by Cattail Foundry. New babbitt main bearings were poured and fitted to the crankshaft. There were many hours spent filling deep rust pits, sanding and painting. My sister Carolyn lettered the cylinder for me.

The skid under the engine was built from locally cut rough lumber and the water tank was a sprayer tank that I disassembled and reconfigured to have a metal tank inside. I wanted all the lumber used to look old so I did some research online and found a method used by model railroaders to age wood. This process took some time but it does work. I purchased all the extra small parts (governor, clutch, oiler, chimney, hot tube, petcocks, oil cups, etc.) form various places. The governor was purchased at an auction in Maryland. It was missing one of the beveled gears. I purchased a replacement from Applied and had it machined to fit. I search for period correct “beaded” pipe fittings to complete the piping for the water and fuel systems. These fittings are difficult to find and sometimes have to be fabricated.

Finally after months of work, the engine was assembled. Now the challenge was to make it run. A few things I did learn about early engines is, generally there is no manual to tell you how to adjust anything. It was all trial and error which involves a lot of cranking or kicking over the engine with your foot on the flywheel. You quickly learn to pay attention to what the engine is doing and where your hands and feet are in relation to the engine.

After months of adjusting and fiddling with the fuel mixture and fuel pressure, the engine seems to start fairly easily and runs pretty well. Most shows it runs for hours at a time although sometimes it gets and attitude and quits. I guess that’s just part of the fun of messing with this old iron.

Paul Stratton

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