Schleicher-Schumm Engine is Find of a Lifetime

Last surviving 10 HP Schleicher-Schumm slide-valve rescued and returned to original condition.

Schleicher Schumm

The finished product: A museum-grade restoration by Wayne Grenning.

Photo courtesy Wayne Grenning

Content Tools

Most engine collectors daydream of the “find of a lifetime”: Waiting in some forgotten barn or pump house, a very rare engine lies waiting, undiscovered, until fortune smiles and this engine comes home. For the vast majority of us, this is only a dream. For Bill Grimley, the dream became a reality. He came upon a 10 HP Schleicher, Schumm & Co. engine in an old factory in the 1970s when he was following up on a lead.

Company history

James and Adolph Schleicher came from Germany to the U.S. and, in 1876, set up a partnership to control N.A. Otto & Cie.’s patents in the U.S., and build and market their atmospheric engines. Before they were able to build any, Otto developed the 4-cycle “silent” engine, and it was this engine that they put into production. In 1877, they were joined by Herman Schumm, in Philadelphia, and set up Schleicher, Schumm & Co. in 1880. Nine engines were built that first year. The earliest engines were flame ignition slide-valve engines designed to run on illuminating gas, which was available in the larger cities at the time. These engines were available as late as 1892. In 1894 the company came under control of Gasmotoren-Fabrik Deutz and was reorganized as the Otto Gas Engine Works.

Engine history

This particular 10 HP engine started out as a single flywheel, slide-valve engine with an integral water pump used for running hydraulic elevators. All 10 HP engines not configured for pumping had twin flywheels, so, to compensate for the lack of a second flywheel, which was replaced by the pump drive gear, the flywheel was cast hollow and filled with lead for extra weight. Where this engine was used in the pumping capacity is unknown. Sometime around the turn of the century, when illuminating gas was phased out in favor of electric lighting, it was converted to poppet valve, hot tube operation, at which time extensive modifications to the head were made. All remnants of the slide-valve seating and guide surfaces were ground off. In addition to these irreversible modifications, the mounting boss for the gas valve was meticulously removed. It was not until the engine was cleaned in the beginning of the restoration that any trace of this surface could be found. The modifications also included a new intake valve chest with a natural gas mixer and hot tube bolted in place of the milled-off slide-valve features. A 5-inch spacer was added to the piston to increase compression, and the governor was set up to open the gas valve more or less as needed, and cutting off the gas entirely when it went over speed. The pump, bearings and drive gear were discarded, and a second flywheel, which was cast using the original as a pattern, was added. It was installed in the Eagle Woodenware Co., Hamilton, Ohio, around 1912, where it ran machinery along with a Hamilton Corliss steam engine.

In the 1970s the Corliss engine was removed from the factory by a couple of steam collectors, but the Schleicher-Schumm was left behind. Bill Grimley was in the market for an Otto-type engine at the time. The Corliss collectors had no interest in the Schleicher, so they put Bill in contact with the owner. He was able to purchase the engine, which was hoisted out of the factory basement with a belt-driven elevator, which would not lift the 7,500-pound load unless liberal amounts of belt dressing were applied. The find of the lifetime thus came home. It was displayed in this modified configuration for many years.

In 2011, Bill, realizing the significance of the engine, decided to have it converted back to its original slide-valve design. Wayne Grenning has extensive knowledge in the operation of slide-valve engines stemming from his work on his 3/4-scale Otto-Langen models, as well as experience with machining and a personal research library that is second to none. He was approached by Bill, and not being one to back away from a challenge, took on the job. The amount of research and machining, pattern making and parts scrounging is documented elsewhere. Go to Go to the bulletin board to see documentation detailing each step of the restoration. The results were nothing short of amazing.

The engine

The engine is one of only eight Schleicher-Schumm slide-valve horizontal engines in existence, and the only 10 HP left anywhere. At no. 1337, it is the fifth oldest Schleicher-Schumm engine in existence and the oldest American-built internal combustion engine in private hands. Much of the original paint was still on the engine since it did not spend any time outdoors. It features a bronze slide-valve along with an extra slide and bearing surface set, all hand-scraped by Wayne, like all original slide-valve engines that he had observed in his research. It also has the original-design gear train with spur and bevel gearing that was commonly used before the advent of spiral gearing found on newer sideshaft engines. It will run on propane as a main fuel source, but it relies on hydrogen for the ignition flame. Hydrogen closely mimics the burning properties of the original hydrogen-rich illuminating gas, and the ignition will not work with anything else.

Details such as the machining “striping” patterns on the bright metal, original-style oilers (and one original), and the exact, custom-made number stamps with the correct font in several sizes for the serial numbers on every part were not overlooked. Custom-made rubber gasbags were made to the original patterns, and cherry skids completed the restoration. The pattern work alone for the recast head is simply incredible. The use of modern 3D computer-aided design (CAD) was essential to this project. All of the CAD work was done by Wayne’s son, Alex.

As with all of Wayne’s projects, the engine runs beautifully. He made a set of weights that can be hung on the governor to change the engine speed. When warm, the engine can be idled down to less than 60 RPM, even though the flame ignition system does not lend itself to slow operation. This is due, partially, to the retention of the original heavy flywheel, in addition to the second flywheel. Although it wasn’t all smooth sailing, the problems, both small and daunting, were overcome one by one. The results speak for themselves.

See the Schleicher-Schumm in action on the Old Iron Videos blog.

Contact Woody Sins at 3 Edna Terr., New Hartford, NY 13413 •