Are 2-stroke diesels still manufactured?

Yes—but almost exclusively for large marine propulsion and certain industrial niches. While 2-stroke diesels disappeared from road vehicles decades ago, they remain the dominant choice for deep-sea ships and still appear in some locomotive, naval/marine, and power-generation roles. Modern two-stroke builders are focusing on cleaner dual-fuel designs (LNG, methanol, and soon ammonia) to meet stringent emissions rules, keeping the technology very much alive in specific sectors.

Where 2-stroke diesels are still built

Today’s 2-stroke diesel production is concentrated in heavy-duty applications where their efficiency and torque are most valuable. The following categories and companies illustrate current manufacturing activity.

• Large ocean-going vessels: Two-stroke, low-speed main engines are still the industry standard for container ships, bulk carriers, and tankers. Major designers and licensors include MAN Energy Solutions (ME-C/ME-GI/ME-LGIM families) and WinGD (X‑DF series), with engines manufactured under license at shipyard engine works in Asia and elsewhere. Japan Engine Corporation (J-ENG) also produces UEC-series two-strokes.
• Alternative-fuel marine engines: New two-stroke dual-fuel models capable of running on LNG, methanol, LPG, and ammonia are in production or entering service, enabling compliance with IMO Tier III NOx and CO2 lifecycle targets. Orders for methanol-capable two-strokes surged in 2023–2025; the first ammonia-fueled two-strokes are slated to enter commercial service beginning in 2025.
• Locomotive, marine, and stationary niches: Progress Rail/EMD continues to offer the EMD 710 two-stroke primarily for marine and power-generation markets, and for locomotives in regions where emissions rules allow. In the U.S., new Tier 4 freight locomotives use four-stroke engines, but two-stroke 710s persist in other markets and in remanufacturing.
• Naval and industrial opposed-piston engines: Fairbanks Morse Defense continues to produce and overhaul opposed‑piston two-stroke diesels for naval and heavy industrial customers, albeit in limited volumes. New opposed-piston military powerplants are also being developed and fielded in low-rate quantities.

In short, new two-stroke diesels are still being manufactured, but the action is overwhelmingly in ship propulsion and specialized industrial/military roles rather than consumer transport.

Why two-stroke diesels endure—and where they struggle

Advantages sustaining production

Two-stroke diesels offer performance and economic characteristics that suit large, slow-turning applications and tightly packaged powertrains.

• Class-leading efficiency at scale: Low-speed marine two-strokes are among the most thermally efficient heat engines in commercial use, delivering very low specific fuel consumption for long-haul shipping.
• High torque and power density: A power stroke every revolution boosts cylinder power, valuable for propeller-driven ships and compact installations.
• Simplified mechanical architecture: Port scavenging and fewer valvetrain components can reduce mechanical complexity in certain designs.
• Fuel flexibility: Modern two-strokes are being delivered as dual-fuel units capable of operating on LNG, methanol, LPG, and—with first commercial units due—ammonia, alongside conventional marine fuels.

These attributes preserve the two-stroke’s appeal where maximum propulsive efficiency and robust torque delivery matter most, especially at the scales seen in oceangoing ships.

Constraints and regulatory realities

Despite their strengths, two-stroke diesels face challenges that curtail their use in many markets, particularly land transport in advanced economies.

• Emissions compliance burden: Meeting IMO Tier III NOx and tightening greenhouse-gas targets requires aftertreatment (e.g., SCR, EGR) and/or cleaner fuels, adding cost and complexity. For locomotives, U.S. EPA Tier 4 effectively pushed new builds to four-stroke platforms.
• Local air quality rules: Stringent particulate and NOx standards in on-road/off-road segments make two-stroke adoption impractical without heavy aftertreatment systems.
• Market consolidation: Only a handful of firms design and license modern two-strokes, with most manufacturing done in specialized shipyard engine plants; this narrows the technology’s footprint.
• Operational considerations: While highly efficient at low rpm, two-strokes are less suited to the duty cycles, packaging, and NVH expectations of light- and medium-duty vehicles.

The regulatory and operational landscape explains why two-stroke diesels survive in shipping and select heavy-duty niches but have disappeared from mainstream road and many rail applications in high-regulation regions.

Notable developments (2023–2025)

The last two years have brought meaningful updates that underscore both continuity and change in two-stroke diesel manufacturing.

• Methanol momentum at sea: Major carriers placed large orders for methanol-capable two-stroke main engines; several methanol-fueled container ships have already entered service with MAN-designed engines.
• Ammonia on the horizon: MAN Energy Solutions and WinGD announced ammonia-fueled two-stroke variants, with first commercial deliveries targeted from 2025 onward, supporting shipowners’ decarbonization plans.
• Efficiency upgrades: WinGD’s X‑DF2.1 with advanced exhaust recirculation and control, and MAN’s latest ME-series refinements, aim to cut fuel burn and methane slip while easing Tier III compliance.
• Locomotive market shift: In North America, new freight locomotives moved decisively to four-stroke Tier 4 platforms (e.g., EMD 1010J, Wabtec Evolution). Two-stroke EMD 710 production continues mainly outside Tier 4 markets and in marine/power-gen roles.
• Defense powerplants: Opposed-piston two-stroke programs—developed with modern combustion and controls—are progressing for military vehicles and generators, with limited production ramping under defense contracts.

These developments show a mature technology adapting through cleaner fuels, better controls, and focused market positioning.

Where two-stroke diesels are no longer made or used

The technology’s retreat from certain sectors is comprehensive and unlikely to reverse.

• On-road vehicles: New two-stroke diesels for passenger cars, pickups, and highway trucks are not produced; the Detroit Diesel two-stroke families ended in the 1990s.
• High-regulation rail markets: New U.S. and Canadian freight locomotives use four-stroke Tier 4 engines; two-strokes persist only in legacy fleets, remanufacturing, or export markets with different standards.
• Light industrial and consumer segments: Packaging, emissions, and noise constraints keep two-stroke diesels out of modern compact equipment and generators, which favor four-stroke designs.

In these areas, emissions regulations, customer expectations, and economics have closed the door on new two-stroke diesel offerings.

Outlook

Two-stroke diesels remain integral to global shipping and a handful of industrial and defense niches. Their future hinges on continued progress with cleaner fuels—especially methanol and ammonia—and on aftertreatment that satisfies IMO and regional rules. On land, the center of gravity has shifted decisively to four-stroke diesels (and, increasingly, electrification), limiting two-strokes to specialized roles.

Summary

Yes, two-stroke diesels are still manufactured, chiefly for large ships and select industrial or defense uses. The sector is evolving toward dual-fuel and alternative-fuel designs to meet tough emissions targets. Outside these niches—particularly in road transport and new North American locomotives—new two-stroke diesels are no longer produced.

Can you get a 2-stroke diesel?

The General Motors EMD engine line is typical of the two-stroke diesel breed. These engines were introduced in the 1930s and power a large number of the diesel locomotives found in the United States. There have been three successive series in the EMD line: the 567 series, the 645 series, and the 710 series.

Do they still make 2-stroke diesel engines?

No, two-stroke diesel engines for most general applications are not still made, as modern emissions regulations, particularly in the 1990s and 2000s, made it impossible for their design to meet required standards, leading manufacturers like Detroit Diesel to switch to four-stroke engines. However, some companies like Achates Power are developing and bringing back two-stroke diesels for military and potentially other applications, utilizing modern technology to improve efficiency and meet stricter emissions targets. 
Why Two-Stroke Diesels Disappeared (For Most Applications)

• Emissions Standards: Two-stroke diesels inherently allow some unburned fuel to escape during the scavenging process, creating higher emissions than four-stroke engines. 
• Regulatory Shift: As emissions regulations, such as those set by the EPA, became more stringent, manufacturers found it increasingly difficult or impossible to meet the new standards with existing two-stroke designs. 
• Rise of Four-Stroke Engines: Four-stroke engines, like the Detroit Diesel Series 60, were able to meet these new standards more effectively and offered better fuel efficiency, leading to a large-scale shift in the industry. 

Are They Still Made At All? 

• Military and Specialized Applications: There are active developments and production of modern two-stroke diesel engines for niche markets, especially military applications, where the advantages of a high power-to-weight ratio and specific design features are critical.
• New Developments: Companies like Achates Power are pioneering new designs, such as horizontally opposed two-stroke engines, with new technologies like common rail injection to create more efficient and compliant two-stroke diesels for specific uses.
• Legacy Engines: While not actively produced for new on-road vehicles, support and replacement parts are still available for legacy two-stroke engines in certain industries like marine, oil and gas, and defense, where their unique characteristics are valued.

When was the last 2-stroke Detroit Diesel made?

The last Detroit Diesel 2-stroke engines were manufactured in 1998 when the company ended production to focus on its 4-stroke engines, primarily to meet new emissions regulations and improve fuel efficiency. While most production for highway vehicles stopped in 1995, other applications and specialty markets continued until the 1998 deadline. 
Reasons for the discontinuation

• Emissions Regulations: Opens in new tabStricter environmental laws enacted in the late 1990s made it difficult to meet the new standards with the existing 2-stroke design. 
• Fuel Efficiency: Opens in new tabThe company aimed to produce more fuel-efficient engines, a goal that the shift to 4-stroke technology supported. 
• Advancements in Engine Technology: Opens in new tabDetroit Diesel itself developed advanced 4-stroke engines with electronic control systems (DDEC), making the older 2-stroke designs obsolete for new applications. 

What happened next

• Detroit Diesel fully transitioned to 4-stroke engines. 
• The 4-stroke Series 60 engine, a pivotal 4-stroke engine for American trucking, became a focus. 
• While production ended, many 2-stroke Detroit Diesel engines continued to be used in existing applications, such as marine and industrial equipment, for years afterward. 

Why aren’t 2-stroke diesels made anymore?

If engines had personalities. This one was a bluecollar workhorse with a lunch pail and a nononsense attitude. But here’s where it starts to shift.