The D.C. & U.

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An early ad for a Tillinghast-built D.C. & U. convertible cylinder.
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This D.C. & U. was photographed in 1964, probably somewhere
near McDonald, Pa., and likely when the engine was pulled from

This particular cylinder caught my interest while working with
Joe Prinzinger on a historical document of the B.D. Tillinghast
Machine Shop (see page 25 of this issue for the full history) in
McDonald, Pa. While the D.C. & U. engine cylinder was one of
the products that Tillinghast built, it was not of his own design.
Tillinghast was the sole producer in building this unique and
apparently once popular engine cylinder, and the patent rights
belonged to three other individuals, Gustave Dahlberg, Jacob
Clicquennoi and Ernest Uhlin. These three gentlemen all lived in
the town of McDonald, and held May 1899 patent numbers 633338 and
633339 for their engineering design of this very unique

The three inventor’s relationship with B.D. Tillinghast is
completely unknown. Were they personal friends, neighbors, or
simply businessmen looking for the right partnership? What we do
know is that their cylinder was extremely popular in the
southwestern Pennsylvania and northern West Virginia oil

The Convertible gas/steam engine is much different than your
typical gas half-breed. As a half-breed simply turned an old steam
frame into a gas-only pumping engine, the convertible cylinders
could be used as a gas engine or a steam engine. The purpose behind
such a concept was to allow an operator to use steam power when the
gas reserves were not available, and the gas engine when the
resources returned. It was much easier than constantly changing the
gas and steam cylinders off of the well.

Although there were several companies that built and patented
convertible engines, the D.C. & U. design seems to have stood
out among the rest. The major noted factor was that the steam chest
was used as a fuel/air mixing chamber, which allowed more room for
a coolant chamber. Other designs used a separate charging area
creating excess weight on the steam frames.

While studying the patents, I noticed some interesting facts. To
begin with, the two patents that were registered show slight
differences in design. The first patent shows the engine, although
a 2-cycle, using an exhaust valve working off of the cross-head.
The second patent shows a traditional ported exhaust, which appears
to have been the more common of the two. The D.C. & U. cylinder
also was built in a rotary steam valve configuration. An old price
list is my only evidence to prove that this design once

Last, I noticed an interesting difference from the earlier
design of the cylinder. The patent design shows a D.C. & U.
patented carburetor. In later designs, and in Tillinghast sales
flyers, you can easily notice that the carburetor that was used was
one of B.D. Tillinghast’s own design, one he used on his
Tillinghast gas cylinders.

The attached photo is a 1964 picture of a D. C. & U. This
picture was probably taken somewhere near McDonald, Pa., when the
engine was most likely pulled from service. The second picture is
from a Tillinghast sales flyer.

This has been an interesting and exciting project. Over the next
several months, I will continue to do research on two other
companies in my hometown of Washington, Pa. Interestingly enough,
these other companies were also builders of convertible engines. I
would love to hear from anyone who has a convertible engine, and
especially anyone that has or knows of a D.C. & U. or
Tillinghast engine. Feel free to contact me at the address below.
Also, if you have Internet access, be sure to log on to the OFES
web site at I will post additional
information and pictures of these great convertible engines.

Contact engine enthusiast Bill Tremel at: (724) 484-0311 or
e-mail at:

Gas Engine Magazine
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Preserving the History of Internal Combustion Engines