As the Coolspring Power Museum’s Air Blast Injection project is progressing well, I certainly understand the confusion about the mysterious Graz Diesel. It will be the third engine in the ABI building, and it will compliment the Augsburg (MAN), and the Benz (not air blast, but significant). This will be a world-class display.
Back in 2019, Gordon Jones, Edith Rice, Tom Rapp, and I made a trip to visit our friend Dr. Friedrich Busch in the small city of Hof in Bavaria, Germany’s southernmost state, to learn how to operate our Augsburg Diesel. He had installed his in the original configuration, showing air tank and compressor location, fuel system design, and all necessary pipe pits. We flew to Munich and drove about an hour to Hof. Our rooms were at the delightful Hotel Burghof and we next met Friedrich for a delicious dinner to make plans for the next day.

The next morning we made the short drive to Friedrich’s home for a special day. We learned all about his MAN Diesel, interrupted only to go to his home for scrumptious snacks, provided by his wife, and look at endless photos and drawings. He explained the compressed air system, the cooling system, and the fuel system. After learning the pre-lubrication procedure, we all had our turns starting it.

We met two of Friedrich’s friends and a great dinner at a local Brewhaus to conclude the day. We felt quite at home.
We viewed his operating Graz but had no idea it would ever come to Coolspring. Surprisingly, in 2020, Friedrich offered it to me providing it be set up at CPM. How could I refuse? Funds were secured and a down payment was made. Friedrich wished we’d return to Hof to learn about its operation and help with the disassembly and packing. It would then be loaded into an awaiting container. The trip sounded exciting and we chose a group to go and had preparations made including airline and hotel reservations. All arrangements were made with a packing and shipping firm and the Graz would arrive that summer.

But then Covid struck. How long would it last? Would it postpone the venture a while? The possibility of obtaining it this year looks bleak. Friedrich and I are remaining patient and it will certainly come to CPM. That is a promise.
Importance of the Graz
The Graz is No. 19 and built in 1904. Being 12hp, it perfectly matches the other two engines in the ABI building. It is the oldest, Austrian-made, operational air blast diesel in the world.
Let’s go over to Austria and visit the small city of Graz. It is a beautiful city and home of Grazer Waggon & Maschinen Fabriks, a firm that became known as a major manufacturer of diesel engines.
Beginning of the 20th Century
Johann Weitzer (1832-1902) had grand plans to manufacture railroad cars, founding a firm in 1854 in Graz, Austria. He chose to build self-powered electric trolleys, as cities all over Europe were replacing their horse-drawn trolleys with the much cleaner new electric ones. He also made railroad box cars for freight and passenger cars. The firm thrived and became a corporation in 1899.


At that time, they began to manufacture diesel engines, licensed from Augsburg. Again, the venture proved successful, and the company became the largest producer of air blast diesels in Austria. Although this did not eclipse the trolleys, their sales increased rapidly. They gained an excellent reputation due to the engines’ solid construction.
Grazer Motor
After 1908, the diesel patents had expired, so instead of having to use “Patent Diesel,” they chose the name “Grazer Motor.” At that time the engines got an extra plate in the finest Art Nouveau design.


The firm was building a 1,000hp engine in 1926 and a mammoth 3,000hp engine in 1933, but the company peaked in 1928 and 1929. Newer designs replaced the air blast system and the marque was last used in 1939. After many mergers, it still exists today as Astra Vagoane Calatori.
The most famous landmark of Graz Diesels is Diesel Centrale in Vienna, Austria. It was in operation from the 1900s through the 1950s. To view all the wonderful photos, go to Diesel Centrale, Austria.

The Graz, Coming Soon
It is a much heavier built engine than the Augsburg, but has a similar operation. The main difference is that it does not have an integral air compressor; instead it uses a belted, two-stage compressor to provide the necessary 800psi for starting and running.

Surprisingly, this does have an advantage. The compressor can be powered by another source such as a small engine, or in this case, an electric motor. Hence, the tanks can be filled for starting, then the belt reconnected to the engine to maintain operating air. A vintage electric motor is used as an alternative power source for the compressor, and we can fill both the Graz and Augsburg tanks. CPM had just the right motor.
Austria-Hungarian in 1615
In Graz, a part of the Austria-Hungarian empire, a settlement of the Merciful Brothers of Graz was founded. Brother Gabriel Ferrara unexpectedly healed the Archduke Maximilian Ernst, preventing his arm being amputated. So the Hospital of St. John of Graz was founded, and has never closed its doors to people seeking help and medical treatment. The Hospital and Convent of the Bramherzigen Brothers remains active today.


The Brothers were very progressive, both in 1904 and today. They offer the finest medical care available, and are proud to be the oldest hospital in Austria. They also have a new facility offering every service imaginable. They welcome all in need, caring for the sick since 1615.
In 1904, they decided to electrify their hospital, ordering two Graz engines, a 12hp and a 16hp, both complete with dynamos and all accessories. Unfortunately the 16hp was lost over the years, but the 12hp is the engine coming to CPM. Friedrich removed it from its original location in 1983, meticulously restored it, and installed it at his location. He has all the original literature, detailed maintenance records, as well as the factory supplied tool board and wrenches.

Preparing for the Graz

Ground has been broken for the new Air Blast Injection building. First, our contractor will establish the floor level, then install the Augsburg and Benz foundations. The Graz foundation will have to wait until we return to Hof to take precise measurements. Friedrich supplied us with a copy of the foundation that he used. It is a great start.
Would you like to help preserve the history of early combustion engine technology for future generations and contribute to CPM’s dream? Make a contribution at the Coolspring Power Museum.
Dr. Paul Harvey, founder of Coolspring Power Museum, is a regular contributor to Gas Engine Magazine and can be emailed at engdoc8@gmail.com.