CSO Hill Jack Plant


There was one known jack plant on CSO Hill (named after California Star Oil Works Company) and one on PCO Hill (named after Pacific Coast Oil Company) in Pico Canyon. Whether there was more than those two, we don't know. I have not seen any pre-1970 photos of the jack plant on PCO Hill. In 1974 and 1975, what was left of both jack plants were salvaged by Greg Johnson and friends (see here for info about the salvage work). Around 1958 Barbara Sitzman Cook took photos of the CSO Hill jack plant, some including her son Merle Cook. Barbara lived in Pico Canyon from 1927-1937 when her father, Charles Sitzman, was the Newhall Oil Field superintendent for Standard Oil Company. Later, she lived in Newhall for many years and often came back to Pico Canyon.

A jack plant (also called a jack house or a pump house) was used to pump many wells from just one location. The main machinery used was a central power unit or just a "power". It was also called an "Allen power unit" after the original patent holder. Either a steam engine or a gas engine was used to provide the rotational motion needed by the central power unit via a belt between the two.

As the belt was rotated by the engine at one end, the other end was rotating around a pulley. The pulley axle had a small bevel gear at one end. Another large bevel gear attached near the bottom of a vertical shaft interlocked with the small gear. These gears converted the motion from vertical to horizontal, rotating the vertical shaft. At the top of the shaft were two eccentric wheels (a wheel with the axle not in the center). As the eccentric wheels rotated, the jack lines (also called jerk lines or shackle lines) would be pulled inward causing the remote jack pumps at the well heads to go up. The downstroke for the jackline would be caused by the weight of the column of oil on the plunger of the pump and the weight of the sucker rods. Sometimes weights were also used at the pump.

The round disk on the top eccentric and the strap around the lower eccentric were free to rotate, so the relative positions of the jack lines would not change - they would never cross over each other getting tangled up. The jackline had to be kept as taut as possible.

The central power unit at the CSO jack plant and the PCO jack plant were probably both powered by a gas engine during their lifetime. There was plenty of excess gas available from the Pico Canyon oil field.


Diagram of central power unit showing the basic parts. The vertical shaft on the two jack plants in Pico Canyon only had two eccentrics, one on the top and one just below that.


Pre-1916 slightly blurry photo of the CSO Hill jack plant in the lower foreground with PCO Hill in the background. Photo taken on CSO Hill. View towards the northeast.

Copyright Note: This image is NOT in the public domain and is protected by the copyright laws of the United States.
Image courtesy of the Robert B. and William R. Moran papers. Mss 282, Department of Special Collections, University Libraries, University of California, Santa Barbara.


About the same view on 1/17/2014


Another image of the CSO Hill jack plant (or jack house) with PCO Hill in the right background. Photo taken on CSO Hill. Unknown date but probably from the 1920's. View towards the northeast, slightly more to the north then the previous photo revealing the derrick for probably CSO 24 (spudded in 1896).

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


CSO Hill jack plant from the Standard Oil Company Booster Magazine of July 1927. This image looks a little newer then the first historic photo because there is a derrick on this photo that has does not appear to be on that photo. View towards the northeast. This is not a pump jack, as the photo caption says.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


About the same view on 1/17/2014


CSO Hill. Jack plant on far left, Star 1 (spudded in 1884) on far right, CSO 24 (spudded in 1896), with collapsed derrick, in middle. View towards the west taken from PCO Hill. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


About the same view on 10/2/2016. The road on PCO Hill is not quite the same as it was in the 1950's making it difficult to duplicate the above photo.


CSO Hill closer view from previous historic photo. Star 1 on the right with collapsed derrick of CSO 24 on the left. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


CSO Hill. Jack plant in middle left, CSO 24 in bottom right, diagonally to the right above the jack plant are the remains of CSO 6 (spudded in 1880). View towards the west. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


About the same view on 10/2/2016. The road on PCO Hill is not quite the same as it was in the 1950's making it difficult to duplicate the above photo.


CSO Hill. Looking up at the jack plant. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


From CSO Hill. Looking down at the jack plant at the lower right with CSO 6 on the left. PCO Hill in the distance. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


From CSO Hill. Looking down at the jack plant. View of the jack lines and how they were run up the hill using supports to keep the lines off of the ground. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


At the jack plant looking north. Engine room on the left. You can see iron rings used as cradles for the jack lines. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


Almost the same photo as above only with kids to give scale. Merle Cook on the right, Phil Sitzman, Jr. on the bottom left, and Gary Sitzman standing on top of the eccentric. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


At the jack plant. Merle Cook on top, Phil Sitzman, Jr. on the right, and Gary Sitzman on the left. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


View of the eccentrics and jack lines. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


View of the eccentrics with the jack lines hooked to them. Some of the lines went straight out and were attached to iron rings hooked to a support beam above. Then another line was hooked to the ring for its journey down the hill to the pump jack at the well. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


View of the eccentrics. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


View of the eccentrics and the many jack lines with Merle Cook on top. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.


Close up of the gears from the previous photo. A belt from the engine would have been attached to the outside of the large pulley on the right. There is a small bevel gear on the end of the pulley axle. That gear interlocks with the large horizontal bevel gear near the bottom of the vertical shaft. The vertical shaft rotates the two eccentrics on the top.


View of the two eccentrics with the jack lines hooked on. Photo taken by Barbara Sitzman Cook about 1958.

Copyright Note: This image is NOT in the public domain and was used by permission of the Santa Clarita Valley Historical Society, Barbara Sitzman Cook Collection.