This is how the Hungarian spark plug – Autó-Motor – was born

For many millions of cars around the world, only six mammoth factories and trusts make the approx. 300 million spark plugs. I wonder why so few factories are involved in the production of this important part? Partly because manufacturers are fearfully guarding the secrets of candle manufacturing — especially their measuring and control equipment — and partly because trusts have tacitly partitioned the world market and in these areas are already stifling any initiatives that could jeopardize their monopoly. Therefore, spark plugs were not made from domestic materials a long time ago, including in Hungary.
István Szilágyi, the young electrical engineer, was very fortunate when he was one of the many hundreds of unemployed graduates in the early 1930s who got a job at the Budapest Electric Works. He worked diligently, but unanimous work did not fill his interests. Although he had no hope that he would ever have a car, he was increasingly preoccupied with the issue of the spark plug. He had valuable ideas a few years later, but the capital was afraid of costly experimentation, and the Bosch family also “protested” against the implementation of Szilágyi’s patent.
By this time, the young engineer already had two patents. One is the bell-insulated, – the other is the low-voltage filament candle. Their news has even leaked abroad, as evidenced by a letter from an Italian company before us. The capitalist interests outright forbade the inventor to enter into the foreign relations necessary for production, but at the same time did nothing to exploit the patents at home.
István Szilágyi’s patents and recent drawings and ideas were dusted there in the desk drawer.
In 1948, returning home from captivity, he barely occupied his old job at Electric Works, and the Ministry of Heavy Industry commissioned him to develop a research plan based on his findings so far that we could make spark plugs from domestic materials. He was also told that previous attempts had failed.
Research work could begin in a small laboratory made available to it in an instrument factory. This is where the enormous potential of our people’s democracy has been demonstrated. The Planning Office, the Ministry and the National Office of Inventions all provided all the help for the experiments that was previously unthinkable. Szilágyi was now finally able to use the lessons of his many years of painstaking experiments and his expertise gained through continuous learning.
Experiments with heat- and spark-resistant electrode materials of unknown composition have begun. According to Szilágyi’s plans, this is the first test engine “brake bench” for the operational and “calorific value” tests of the finished spark plugs. He had to design and have a whole range of hitherto unknown measuring, control equipment and instruments.
Among many other difficulties, the issue of the quality of insulation materials has arisen. While he was aware that so-called “corundum” materials are commonly used for spark plug insulation around the world, he was also aware that their production required a special kiln heated to 1800 ° C. The requested factories and ceramic experts knew and undertook to produce the material, for which the raw material – alumina (bauxite) – was available to us in almost unlimited quantities at home. However, they did not have the 1800 degree furnace required for firing.
Here, engineer Szilágyi met the first big obstacle.
However, the anticipated confidence and love for the task provided a force that would have overcome an even greater obstacle. He recalled that in the 1940s, in the research laboratory of the Drasche porcelain factory, dr. A herbal chemical engineer conducted successful experiments with the then-emerging new chemical, sinter corundum, which seemed suitable for making spark plug insulators. The experimental dr. He searched herd in vain, finding no trace. He also remembered that the Drasche factory had a small 1,800-degree experimental furnace. The chase after the furnace began. He found it for a long time, but in a useless condition. Who could repair and install it?

Chief engineer of Szilágyi with his own control instrument. A special current of 100,000 volts conducted through the insulator body draws a huge arc of light between the poles of the instrument

We need to find Csordás’ former laboratory subordinate, chemist József Pétery, who worked with this furnace before the war. After a long search, he found it and his joy only intensified when Pétery stated that he would not only undertake the commissioning, but also remember the corundum material and make it. It took almost a year for the furnace to be set on its feet, searched for and found, and then supplemented with the high-temperature-resistant liner.
After all, after overcoming so many insignificant obstacles, the first Hungarian spark plug was completed in the autumn of 1949. Undoubtedly, the “newborn” was not flawless. The ceramic experts believed that the work of the Szilágyi family could not bring results. But the superiors tended to rely on the enthusiastic electrical engineer and provided him with an experimental laboratory with very valuable equipment in Székesfehérvár.
Fehérvár proved useful for a year. By this time, new news and announcements about the insulating production of some spark plug factories were already leaking. It turned out that the high firing temperature of 1800 ° C was more misleading in the individual descriptions than the candle insulator, because it is not feasible on an industrial scale. Thus, among other things, the seemingly uninteresting high firing temperature was traced from 1800 ° to 1650 °. Nevertheless, the insulating material retained all its good properties.
Choosing which of the many types of insulating compositions is most suitable for a spark plug would have taken many, many long months with previously known methods. Szilágyi edited and perfected an electrical measuring device with which all the data characteristic of a candle insulator can be determined in minutes. With this procedure, which is unique in the world, it is possible to reveal possible defects in the insulating body, which would otherwise only occur on many thousands of kilometers of test drive. With the device, the baby is heated to 2,000 degrees in an area of ​​barely a square millimeter, through which the path of 30-1,000,000 volts of special current passed through it reveals all the properties of the material. But here Szilágyi implemented even more of his ideas. He did the so-called oil suction pole, which prevents a hitherto almost ridiculous fault in the spark plugs, the so-called “oil short circuit”.
Unlimited experimental possibilities allowed him to implement another invention that grew beyond the borders of the country. He made the world’s first usable glass candle. By using a glass tube insulator, it has achieved what has hitherto only been possible on laboratory test engines by incorporating a quartz window – that it can be seen into the “kidney” of the engine during operation. It can be determined whether there is a normal ignition in each cylinder, whether combustion is perfect during the explosion, whether the carburetor is dosed correctly, and so on. A high-performance car ran 40,000 miles with experimental glass candles. (“Car-Engine” also reported on these candles at the time.)
The candle factory moved to Pesterzsébet as the last and final stop. Here it was officially called. “SPARK PLUG FACTORY”: the large letters on the facade of the building under the even bigger red star boast. But here, too, there were obstacles around construction and equipment. It caused a lot of problems e.g. design of a special tunnel kiln. Here, as in other areas of the work, the Soviet literature was of great help: among others, the articles of NP Stepichev, a Stalin-winner spark plug expert, and the publications of the thick volume of “Masinisztroenije”.
The construction of the Spark Plug Factory posed new problems for the researchers. Led by Szilágyi, a committee at the “Isolator” candle factory in Neuhaus went on a study trip to the German Democratic Republic at the end of last year, where hosts and guests exchanged experiences. An engineer from Szilágyi learned a lot from mass production technology, and German engineers adopted the principle of Szilágyi’s high-voltage candle insulation test.

In April of this year, after a lot of work, the cutting machines finally started. The mill, which grinds the baby’s raw material, alumina, to a finer size than flour, has started operating, and the large furnace that has been built in the meantime has been heated, from which thousands of insulating bodies fired from domestic materials come out, the composition of which is roughly the same as the best foreign candles. Finally, the first Hungarian spark plugs in the series were completed (from the first series, the National Automobile Experimental Station also received an investigation, the review of which was described in a few words in the previous issue of our paper).
The increasingly dynamic production allows chief engineer István Szilágyi to take his favorite job again, “move” to the laboratory richly equipped with expensive instruments, where he can continue with the glass-insulated candle, and now he can complete his successful experiments so far.
“I am most proud of the awards I have received so far,” said the otherwise very modest István Szilágyi, But I am aware that I could never have achieved these results without the help of my enthusiastic manual staff.

György Rózsa


Source: Autó-Motor by

*The article has been translated based on the content of Autó-Motor by If there is any problem regarding the content, copyright, please leave a report below the article. We will try to process as quickly as possible to protect the rights of the author. Thank you very much!

*We just want readers to access information more quickly and easily with other multilingual content, instead of information only available in a certain language.

*We always respect the copyright of the content of the author and always include the original link of the source article.If the author disagrees, just leave the report below the article, the article will be edited or deleted at the request of the author. Thanks very much! Best regards!