New engines coming from Zenith Power Products

The 1.6 L engine, shown here on the assembly line in Tomahawk, Wis., has been a popular size for Zenith Power Products. (Photo: Chad Elmore)

Zenith Power Products has been busy over the past several years. The company moved its headquarters and engine production from Abingdon, Va., to Tomahawk, Wis., in 2020 and with that came a renewed focus on the gaseous-fuel engine platforms that were core to its business. During that same year, the company’s owners brought on Lee Oberto as Zenith’s president, an engineer with a resume that includes work with Caterpillar’s 3600 large bore engines and as a professor at Michigan Tech.

Zenith Power Products is adding on to its factory in northern Wisconsin, shown here in early May 2025. (Photo: Chad Elmore)

Today, the company is in the process of doubling the footprint of its dedicated factory (a former Harley-Davidson plant) in northern Wisconsin, and there are already plans in the works for a third expansion.

Oberto said the company needs to increase its footprint to help it keep pace with the demand of its current products, including its popular Zenith NAG416 spark-ignited 1.6L gaseous-fuel engine line. Based on a water-cooled gasoline engine sourced from Hyundai Motors, the engine can be found in equipment ranging from concrete pumps, generators, air compressors and even a special-purpose vehicle designed for traveling across frozen lakes.

The factory expansion in Tomahawk is also required to ensure it is ready for new engine sizes that the company has under development.

First up will be 2.4 and 3.4L natural gas and propane engines for industrial applications and power generation. Under development for two years, these are diesel-based engines developed for prime power, continuous duty and or standby applications.

The company’s NA665, an inline six-cylinder 6.5L engine has also been popular. “We sell a lot of these engines in West Texas for vapor recovery in natural gas compression, and we do some power gen and a lot of irrigation applications with it,” said Mike Samoorian, who joined Zenith in a sales role back in 2017.

Oberto said testing is complete on 2.4L and 3.4L engines, each based on HD Hyundai Infracore (HDI) diesel engines that are popular in forklifts, , and they will be the next to join the Zenith line up. Both engines use a gaseous fuel system from EControls along with other changes.

Zenith Power Products’ 3.4 L gaseous fuel engine. (Photo: Chad Elmore)

The inline four-cylinder 2.4L engine is available in two separate fuel options, or dual fuel. P24 (for LPG) is rated 45kWm at 2500 rpm or G24 (LNG) is rated 39 kWm at 2500 rpm. The larger inline four-cylinder 3.4L engine is rated 55 kW at 2,500 rpm for the P34 (LPG) or 49 kW at 2,500 rpm for the G34 (LNG).

“We’ve got some of these out there in the field right now running, and they’re pushing 10,000 hours now,” said Samoorian. “The customers have said, ‘we haven’t done anything. We’ve just changed oil in them.’ It’s a fantastic engine. It’s got hydraulic lifters so there’s no maintenance on the head, which is great in pump applications or generators where it’s just expected to run. The ones we have out there now are in a continuous duty application. They’re on vapor recovery in gas compressors so they just run and run and run. It going to be a really good product for us.”

“Our product launch road map includes a lot of new engines, and the 3.4L and 2.4L are just the first two,” said Oberto. “We’re planning five or six new launches in the next three years. Soon, we will have engines in our catalog that range from 1.6L to 24L. There is a lot of stuff happening, and we have the financial commitment we need to develop the engines.

“We’re also excited about the engineering relationships we have with our suppliers like HDI, which we have access to the engineers who actually do the heavy lifting. It’s amazing, because that access completely changes how we can develop a product. We have the support of hundreds of engineers.”