Surface Machinery and Methods for Oil-Well Pumping

renewed should be fitted in the shop before assembling. The engine
should be firmly mounted on a concrete block and properly aligned
with the band wheel or countershaft pulley. Improper alignment
will always cause belt trouble. Poor alignment of the crank shaft
and clutch is indirectly responsible for much bearing trouble. There
must be no leaks in the water and gas lines. Suitable gaskets should
be properly placed in the engine, and any compression leaks cor-
rected. Knocks in the crank shaft or piston should be corrected as
they prevent good lubrication and vibrations from them will eventu-
ally cause a breakdown. The caps must be kept down on the shaft
bearings, or the bearings will pound out before they wear out. The
flywheel should be firmly keyed or bolted to the shaft to prevent
play. As a matter of safety to the workmen the key should never
extend beyond the end of the shaft. The gas-supply pipe should
be large enough to meet the needs of the engine. The proper size
can be determined as follows: Multiply the horsepower rating by
0.03 and add 0.75; this gives the minimum diameter in inches. The
exhaust pipe should be as straight and free from bends as possible,
and its diameter should be between one-third and one-quarter of the
cylinder diameter.
One of the largest operating companies supplied the following
data on gas engine operation and maintenance, based upon the use
of a 30-horsepower engine.
We estimate that the life of an oil-well engine is 15 years and its gas
consumption 10,000 to 12,000 cubic feet per 24 hours.
Our gas-engine crew consists of one foreman and two helpers. They take
care of 37 engines operating continuously at wells pumping "on the beam,"
repair engines operating central powers or jack plants when necessary to
work on these wells, look after the countershafts at motor installations, and
make practically all belt repairs and replacements.
The average annual maintenance cost of the gas engines operated
by this oil company, exclusive of interest, taxes, and depreciation, is
shown in Table 1.
TABLE 1.-Engine maintenance exclusive of interest, taxes, and depreciation.
(Cost per year, engine operating continuously.)
Materials :
1 set clutch bushings, renewed once a year_----------------------- $60. 30
1 exhaust valve-------------------------------------- 2.25
1 exhaust clutch, renewed every 5 years at $42.30 __ 8.46
1 set clutch shoe blocks a year------------------------------ 13.68
Reboring cylinder, every 5 years at $20 ---------- --------- 4. 00
Water pump, 32 feet 3 inches, 3-ply rubber belt at $0.20 6. 40
1 set magneto tension springs a year _- 50
Miscellaneous bearing metal, wiring, spark plugs, etc_ ___ 10. 00
105. 59

George, H. C. Surface Machinery and Methods for Oil-Well Pumping. Washington D.C.. UNT Digital Library. Accessed November 25, 2015.