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January 2015

Clark Sintz: The Early Years

By Paul Harvey

Beginning my fifth year of writing the monthly Flywheel articles, I chose the rare and obscure Clark Sintz engine located in the Founders Engine House at Coolspring Power Museum.  At first, fearing that little information would be available, I soon became overwhelmed with the detailed story of this ingenuous inventor, deciding to make this a two-part article.  Researching Clark Sintz on, I became acquainted with Bob Sintz, Clark's great-grandson.  I am indebted to him for all the information and dialogue that he provided, some of which is used in this article.  This month, I will present a discussion of Clark's early years in Springfield, Ohio, followed next month by his later career in Grand Rapids, Michigan, and New Orleans, Louisiana.  And so, our fascinating story begins.

Clark Sintz was born at his parents' farm located near Springfield, Ohio, on May 9, 1850.  His grandfather had settled there in 1797.  Young Clark was an inventor from birth and, at age 12, he built a toy steam engine from an old pistol barrel and copper tea kettle!   In 1868, he made a slide valve steam engine. When only 20 years old, he obtained his first patent, number 107,110, for a corn plow and cultivator.  Refer to Photo 1.  In 1877, he built his own small machine and blacksmith shop and repaired farm equipment locally.  Here, he designed many novel devices to make his work - as well as the neighboring farmers work - easier.  He became aware of the gas engine when learning about the Otto Gas Engine at the Centennial Exhibition in Philadelphia in 1876.  Fascinated with this new power source, he started his first experiments in 1883.

In 1874, according to the U.S. Census Records, he married Virgie Littler, who became his lifetime companion. They resided in Springfield, Ohio, where he operated his shop and delved into gas engine experimentation and design.  He was indeed a pioneer in this venture, along with Charter of Sterling, Illinois, and Van Duzen of Cincinnati, Ohio.  These men were on their own as there was nothing to copy from - just try it and see if it works!  While in Springfield, two sons were born; Guy in 1875 and Claude in 1876.  They both followed their father's love for gas engines.  Together, they moved to Grand Rapids, Michigan, in 1893, and that story will be told next month.

Clark's first engine was patented in 1886, number 339,225, and is shown in Photo 2.  This was a two-cycle marine engine using the Clerk cycle, which employed a separate charging cylinder from the power cylinder.  It was one of the very few American engines to have open flame ignition.  Apparently, it was successful as it powered his boat for demonstrations, and amazingly it used gasoline both for fuel and the ignition. It is unknown how many were built, and, being so complicated, this could have been a prototype.  Soon after, he invented the electric "make and break" ignitor.  As noted in patent number 383,775 of 1888, it was a sliding spindle device, which eventually became common with later builders in southwestern Ohio.  This feature greatly improved the performance of his engines.

Although there are several different versions of the following story, I have tried to compile the most reasonable.  Sintz had an early association with Charles Endter and John Foos, both of Springfield.  It seems that Sintz and Endter designed a four-cycle gas engine which was then patented by Endter and Foos. This patent of 1893, number 494,134, is shown as Photo 3.  Strangely, this engine was being built and sold in 1891, perhaps even earlier.  Together with P.P. Mast of Springfield, Sintz, Endter and Foos formed the Gas Engine Company in 1888 to develop and produce a new engine. This patent appears to have been their result. The Gas Engine Company lasted only until 1890 when Sintz sold out to Foos.  Foos continued with the well known Foos Gas Engine Company while Clark formed the Sintz Gas Engine Company.  Both claimed to have made improvements of their own on the patent and to be building a better engine than the other.  There is no further mention of Mast's nor Endter's involvement.  So both Sintz and Foos produced very similar and successful machines.

Photo 4, the Sintz four-cycle vertical engine and Photo 5, the Foos four-cycle vertical engine are shown together for comparison.  The engine frames, the flywheel and crankshaft, and the governor are identical.  Sintz used a single valve chest on one side of the engine with two vertical valves and the sliding spindle ignitor between, while Foos utilized a "T" head design with valve chests on both sides.  This arrangement became so typical of all later Foos engines. Sintz used his patented sliding spindle ignitor while Foos, with Endter's help, developed their long-lasting "wipe spark" ignitor, located on the side of the intake chest.   Both of these competing designs were successful. Clark expanded his design by including a four-cycle, twin-cylinder marine engine as noted in Photo 6.  The two Sintz engine photos were from an 1891 brochure which was found in this envelope, Photo 7.

Short-lived, the Sintz four-cycle engines were made only in 1891 and 1892.  The engine displayed at the Coolspring Power Museum was made during this era.  It will be described in detail later in this article.  It is presumed that Endter's and Foos' influence turned Clark away from the two-cycle design of his original engine, for a trial of the four-cycle principle.  By 1892, Clark, and the Sintz Gas Engine Company, had returned to his first love, the two-cycle engine.  Although there was no navigable water near Springfield, Ohio, his main interest turned to marine engines.  The firm did manufacture a two flywheel stationary model as well.  This venture seemed to prosper, and the 1892 U.S. Cities Directories noted Clark and his family living at 222 Cedar Street, Springfield, and his firm located at 172 West North Street in Springfield, Ohio.  Always on the move, the  U.S. Cities Directories of 1893 notes that Clark was now in Grand Rapids, Michigan, and was president and superintendent of the Sintz Gas Engine Company.  It was located at 242 Canal Street.  This story will continue in next month's article.

Photo 8 is Clark Sintz at the Colombian Exposition in Chicago, Illinois, held in 1892 and 1893.  Clark, who would be an unknown among the famous inventors there, decided he would attend and make his presence known.  He transported a wooden vessel of his own manufacture, powered by his two-cycle engine, and placed it in Lake Michigan adjoining the big show.  His boat and engine performed flawlessly and soon he was giving executives and inventors tours of the Chicago lakefront.  His fame soon spread and he gained this portrait as well as many significant contracts for his engine.  This was the beginning of his relationship with the Michigan Yacht Club and a successful future in Grand Rapids.

While still in Springfield, Clark resumed his research and design of a dependable, two-cycle, gasoline engine.  A stationary version of this development was featured in Cassier's Magazine in 1893.  This handsome and successful engine is shown as Photo 9.  Sintz had a total of 17 patents but his most important one was number 509,255 of November 21, 1893.  Seen in Photo 10, it is his three port, gasoline injected engine, which utilized a piston tripped electric ignitor.  Apparently different enough from Joseph Day's patent in England, there was no infringement.  This design used no valves and scavenged the intake air through the piston.  The fuel injector was in the cross-over port and the rapid air flow inducted the fuel.  This design became the standard of so many two-cycle engines still built today.  He now had an engine that would sustain both his marine and automotive ambitions.

Looking ahead a bit, Photo 11 is a Sintz advertisement of 1902 as shown in Harper's Magazine.  At that time, the company, then in Grand Rapids, Michigan, was very successful. Clark must have been very happy to see his two-cycle engine made in so many sizes and offered in so many launches and yachts! Unfortunately, very few of Clark Sintz's marine engine still exist today.  Photo 12 shows a beautifully restored example on display at the Penobscot Marine Museum in Maine.  Note the lever that controls both the pitch of the propeller and the governor.

Moving ahead a century or so, I will detail and describe the Clark Sintz engine displayed at Coolspring Power Museum.   Located in the Founders Engine House, this engine is shown in Photo 13. It was manufactured in 1891, and, to my knowledge, is the only four-cycle Sintz engine existing.  I purchased the engine at an auction of the contents of a tumbledown shop near the Allegheny River in Freeport, Pennsylvania, in 1971.  Recognizing it as a very old engine, one unknown to me, I was able to purchase the frame with crankshaft and wheel for $3.00!!  These parts just have to be significant!  After the auction, I was permitted to search the piles of junk for parts, and was rewarded by finding the head and valve chest, as well as several other small parts.  It appeared more like an engine then. However, it languished at Coolspring for many years before it was "restored."  Not knowing the exact appearance of the missing parts, they were fabricated to appear correct and to be functional.  The job went amazingly well and the engine now runs.

Photo 14 details the valve chest on the museum's engine.  Note the power operated exhaust valve to the left which operates from a cam.  The reconstructed sliding spindle ignitor, in the center, has an intricate trip mechanism that is activated by the cam shaft. The atmospheric intake valve is to the right, and shows both the gas and air pipes entering the mixer.  The pipe sizes suggest that this engine was intended to operate on gas and not gasoline. Photo 15 shows the timing gears, governor, and fuel valve.  The timing gear and gas valve are original, found in the junk pile, but the governor has been reconstructed.  Finally, Photo 16 is the original and ornate brass name plate.  Note that the last patent listed is 1890!

This concludes the story of the early years of Clark Sintz in Springfield, Ohio.  Next month will continue with the rest of his career.

Coolspring Power Museum is now closed for the winter but tours can still be arranged by advance notice.  Please call 814-849-6883 or see our web site at for events and developments.  See you then!

Sintz First Patent

Photo 1: Sintz patent for a corn plow and cultivator

Sintz First Engine Patent

Photo 2: Patent for Sintz's first engine

Foos Endter Patent

Photo 3: Patent for four-cycle gas engine

Sintz Four-Cycle Engine 

Photo 4: Sintz four-cycle vertical engine

Foos Engine 

Photo 5: Foos four-cycle vertical engine

Sintz Four-Cycle Marine Engine 

Photo 6: Sintz four-cycle, twin-cylinder marine engine

Sintz Envelope 

Photo 7: Envelope that contained 1891 engine brochure

Sintz Columbian Exposition 

Photo 8: Clark Sintz at the Columbian Exposition

Sintz Cassier's Article 

Photo 9: Stationary two-cycle gasoline engine

Sintz Two-Cycle Three Port Patent 

Photo 10: Sintz three port, gasoline injected engine

Sintz Ad of 1902 

Photo 11: Sintz advertisement of 1902

Sintz Marine Engine 

Photo 12: Sintz marine engine

CPM Sintz Engine 

Photo 13: Sintz engine at the museum

Sintz Valve Chest Detail 

Photo 14: Valve chest on the museum's engine

Sintz Governor Detail 

Photo 15: Timing gears, governor, and fuel valve

Sintz Name Plate 

Photo 16: Brass name plate


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