Gas Engine Magazine

Old World Charm: 1918 3-4hp Lorenz Engine

By Staff

Manufacturer: Ignac-Lorenz Co., Kromeriz, Moravia, Czechoslovakia
Year: 1918
Serial No.: 7130
Horsepower: 3-4hp (rpm not listed)
Bore & stroke: 4in x 6in
Flywheel: 23in x 3in
Ignition: Spark plug w/magneto
Governing: Hit-and-miss, sideshaft governor
Cooling: Tank, thermosiphon

Large red flywheel of engine

Engine enthusiast Rudy Adrian had been keen on getting a Czechoslovakian-made Lorenz engine for years. Why? For starters, his wife, Xenia, is of Czechoslovakian heritage; her grandfather emigrated from Czechoslovakia and settled in Ohio. Plus, he just liked how they looked. “Years ago at the Baraboo, Wisconsin, show, a fellow had a Lorenz engine,” Rudy says. “I liked the way it looked. It still had the factory cart on it, and the wheels were neat-looking. It was very European in appearance.” But finding one in the U.S. took a bit.

A man in a red shirt and blue jeans standing next to his black and…


Finding a Lorenz

For many years, simply wanting a Lorenz was as far as Rudy’s aspirations went. But then one day he was talking to a customer at his magneto and igniter repair shop, Adrian’s Magneto Service. “We were just chatting on the phone about engines, and he asked if I had bought anything lately. I said, ‘No, I’m kind out of room, but I would like to buy a Lorenz engine, so if you ever come upon a small Lorenz that’s for sale, let me know.'” Rudy didn’t expect the immediate response he got. “I have too many engines, too, and I have a small Lorenz I would let go,” the caller said. Naturally, Rudy jumped at the chance to buy the engine.

Copper name plate

Not much is known about this particular 3-4hp Lorenz engine or how it made its way to the U.S. from Czechoslovakia, where it was manufactured by the Ignac-Lorenz company in 1918. Founded in Kromeriz, Moravia, in 1882, Lorenz established a factory for the repair and manufacture of agricultural machinery. The company was still in business after World War II, but when the Communist government came to power it seized the Lorenz buildings and machinery, and the company ceased production. How Rudy’s Lorenz got to Canada remains a mystery.

A close-up showing the Lorenz’s unique carburetor/mixer with atmospheric fuel valve.

When Rudy got the Lorenz, it was in good shape. “It was in the condition you see it now, but it had a couple of problems,” Rudy says. The magneto was fine, as Rudy had already rebuilt it for the former owner some years earlier, but the mixer/carburetor wasn’t working properly, something he discovered when he took it to a show shortly after he bought it. “I had a lot of problems with flooding and over fueling, so I took the mixer apart and made necessary parts on my lathe to get it to work.”

Rudy also had to tend to the governor, as the engine was running far too…

To get the governor working properly, he removed the side shaft rocker arms on the governor and rewound a new governor spring out of piano wire. Rudy used piano wire because its light gauge means it doesn’t take much to engage the governor and keep engine speed in check. “It took me three springs until I got it figured out,” Rudy says, adding, “A lot of engine work is hit-and-miss, no pun intended.” Rudy says the late Lee Anderson, who was a well-known engine collector, got him started using piano wire for governor springs. “It seems to be the best thing to use for springs. It comes in many different gauges.”

Ignition is via spark plug and high-tension magneto. Note the cowling on the mixer to…


On most hit-and-miss engines, the governor acts to hold the exhaust valve open, which keeps the atmospheric inlet valve from opening to draw in a fresh charge of fuel and air, thereby allowing the engine to coast. “But the Lorenz doesn’t work like a regular hit-and-miss,” Rudy notes. “There are two valves, the intake and one in the mixer. Fuel from the gravity-flow gas tank goes into a holding chamber in the mixer until the sideshaft moves the intake rocker and the engine calls for fuel, and then it fires. When it reaches governed speed it moves the cam on the sideshaft and holds the intake valve open.”

Rudy’s been a mechanic all his life, and says that figuring out how certain things work on an engine is sometimes straightforward, and sometimes a matter of guesswork. “The basic concept is always the same on a 4-stroke, but in the early days everyone figured they knew the best way to build an engine, so we have all these different types of engines. Everyone thought they had a better idea, and they didn’t have fancy machinery to make this stuff. It was all old-school world craft, and all done by hand. It’s amazing.”

Engine notes

The Lorenz is tank-cooled, relying on thermosiphon for water circulation. “The cooling tank is filled with water, which flows into the water jacket in the engine through a pipe. As the engine warms up, heated water rises up through the engine and back into the cooling tank at the top of the tank, and the cool water below flows into the cylinder jacket. It’s just like an old tractor or anything that cools without a water pump.”

The cart is an integrated part of the Lorenz engine’s layout.


The Lorenz is a side shaft engine with a semi-enclosed crankcase. “A closed crank usually has a cover on it, but the Lorenz has a one-piece block. It’s open on the side and the top is part of the main casting.”

Rudy says the 1918 Lorenz is a quality engine. “It’s a very well-built engine. It has brass bearing boxes on the connecting rods, and brass main oil well bearings. That means a longer life for the engine because it’s constantly running in oil. One young guy said he could tell it was a quality-made engine because he had Czechoslovakian cameras, and they were of good quality.” He’s also impressed with how well it runs. “I had a fellow comment that he had seen Lorenz engines on the internet, but never knew they could run slow like mine.”

A tag attached to the cart warns – in Czechoslovakian – the operator to drain…


An unusual aspect of the Lorenz is its horsepower rating, which is between 3hp and 4hp, depending on how fast it is run. “There’s a little spring-loaded knob at the front of the engine next to the side shaft,” Rudy says. “When the spring is tightened up, the engine runs fast because it puts pressure on the governor. It takes more rpm to overcome the spring pressure on the governor, so it runs faster and horsepower output increases.”

Looking forward

Rudy says he’s heard gloom and doom stories about the future of gas engine collecting, but he doesn’t buy them. “I remember about 1998, when a number of the old-timers passed away, and there were empty spots in the engine areas at shows. I’m in the magneto business, and it hasn’t slowed down. Whenever I talk to people, I invite them to attend our shows, especially Rollag, because I discovered that a lot of collectors kept their engines in the barn or wherever and were staying home and not taking them to shows, so the machines never saw daylight. But today, all the spots at the huge Rollag, Minnesota, show (Western Minnesota Steam Threshers Reunion) are filled. Rollag did not have a single gas engine spot left this year.”

A close-up of the sideshaft, magneto and intake and exhaust rocker arms.


Rudy adds that interest in gasoline engines at shows has to do with the interest of the people running the show. “If they really care about gas engines, there will be more gas engines there. Take a show like Baraboo. They have lots of gas engines, and they just bought more land.”

Cylinder head view of the Lorenz.


As for the Lorenz, he says it fits in nicely with the rest of his collection, which is mostly made up of farm engines. He likes that it’s a sideshaft, and that it was made in Europe and not made in the U.S., a fact that makes the engine that much more interesting to him, and other people.

Contact Bill Vossler at Box 372, 400 Caroline Ln., Rockville, MN 56369;

  • Published on Jan 14, 2020
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