The 8LV Marine Diesel: An Engine for the Needs of our Times


Reading Time : 4mins

The world’s leading yacht race, the 35th America’s Cup, is almost upon us. Yanmar will be supporting this prestigious event as the Official Marines Engines Partner.

We have previously introduced Yanmar’s relationship with the America’s Cup. Yanmar will again be providing the chase boats of defending champions Oracle Team USA with high-performance 8LV marine diesel engines and ZT drive systems. Not only were Yanmar engines chosen by the top team in this most demanding of high technology sports for their power, endurance and environmental performance, Yanmar’s marine diesel engines will also be used on the VIP shuttle boat, which takes guests out to the race course area to watch the best sailors in the world compete for the oldest trophy in international sport.

The 8LV marine diesel delivers a daunting 370 hp for smooth and powerful acceleration in a compact, low-noise, low-vibration engine. Incorporating Yanmar’s cutting-edge diesel technology, it is an advanced marine leisure boat engine for the next-generation.

We bring you an interview with the team behind this remarkable engine. They overcame the challenges of meeting strict emissions requirements, and developed the technologies needed to meet the demands of our times. As the engine prepares to play its vital role on the auspicious occasion of the America’s Cup, we bring you the inside story of this extraordinary engine.

ShigaKenji Shiga
Power Solution Business
Industrial Power Products
Management Division
Marine Engineering Division
Engine Development Division

【Profile】Kenji first joined Yanmar in1986. Following on from his role in the development of industrial engines, from 1991 Kenji dedicated his work to researching how to reduce emissions at the Oyamazaki research center in Japan. In 2000 he returned to the Nagahama factory where he specialized in developing marine engines.

OgataTomoo Ogata
Power Solution Business
Industrial Power Products
Management Division Engine Development Division
Testing Division

【Profile】Tomo joined Yanmar in 2006. He began working at Yanmar in 2006 following university studies relating to internal-combustion engines. At Yanmar he worked in the testing department at the Nagahama factory and 10 years later started working on testing for small marine engines.


Emissions Regulations Provide Opportunity For Larger Leaps Forward in Engine Performance.

Yanmar’s inline 6 cylinder 6LP marine diesel engine remained a mainstay product in the 300 horse power range pleasure boat use engine market, where demand remains high, since the commencement of its large-scale production in 1997. The introduction of the Tier 3 emission regulations by the United States Environmental Protection Agency (EPA) in 2012, however, necessitated a move away from the conventional mechanical fuel injection style engine design towards a common rail equipped electronically controlled engine. Meeting the Tier 3 regulations compounded by Yanmar’s continuous pursuit of furthering productivity is what led to Yanmar’s 8LV marine diesel engine.

Overcoming Rising Issues to Marinize the V8 Engine

From Yanmar’s 8LV base engines, the 4.5L V8 engine was chosen and designed for application on boats. Due to the spatial limitations of pleasure boats, auxiliaries such as the supercharger and the cooling system needed to be fixed to the side of the engine. For this reason the team had to devise the parts layout, on top of designing an engine with reduced vibration and noise to combat increases in the engine’s size and weight. Technology to marinize engines has been developed and refined over decades at Yanmar. However this time, as the team was working with a new base engine, the entire process needed to be reconsidered.

Kenji Shiga, who was looking after the design talks to us about the struggles he came up against at the time.

Shiga“30ft class pleasure boats have 2 engines alongside each other and 2 shafts. The V8 cylinder engine is a lot wider that the inline-6 cylinder and figuring out how to equip the engine in the same space as was used previously was the biggest issue.”

The cooling and power devices, which up until now had been attached horizontally to the engine, were fixed to the upper part of the engine. By implementing strategies, such as a including a cover which comes down over the devices, the team managed to solve strength and vibrational issues.

More Power with 370 Horse Power

In order to meet demands to increase the capacity of the connecting drive unit, the team needed to devise a way to optimize the power output of the engine.

Ogata“At the outset, the goal was to create a 350 horse power engine, however as development progressed we realized that this could be further raised to 370 horse power”

notes Tomo Ogata, who was overseeing testing of the engine.

Ogata“Actual testing of the engine provided us with an achievable goal to aim towards. This fueled our motivation to bring that goal into a reality.”

We conducted testing over and over again, inspecting the heat and stress caused by load on the engine itself and synchronizing the supercharger, each time coming closer to what we were aiming for.

Furthermore, by creating a Yanmar original power train with an electronic control unit, drive unit and reverse-reduction-gears, we were able to deliver an engine which offers high reliability and propulsion performance. Fusing together all of Yanmar’s technologies and 3.5 years of development, in January 2011, the 8LV engine was complete, signaling the start of the next generation in marine engines.

Recognized by Champions for Top Performance

The 8LV has been praised for its smooth operability, low vibration and quiet running

The 8LV has been praised for its smooth operability, low vibration and quiet running performance by users who have equipped the engine to their vessel.

Shiga“The desire to build an engine to please our customers was the motivating force behind the development of the 8LV. Everyone involved in the making of this engine, can say so with absolute pride,”

says Kenji.

Furthermore in 2013, the 8LV was used on the chase boats of the current two time successive champion of the America’s Cup, Oracle Team USA, highlighting the engine’s superb performance capabilities.

Ogata“We want the marine pleasure department to take the lead when it comes to Yanmar technology. Solving rising issues and potential needs of our customers with technology, while also leveraging it for industry”

stated Tomo. The team members’ passionate outlook to challenge past limitations continues.

While with the development of a new engine comes a multitude of challenges and the team’s key determination was to deliver absolute reliability. On the ocean where engine failure puts people’s lives at risk, increasing the quality of each device ensures that the engine continues to run in any condition and at all times.

“For Yanmar, there are no compromises in this area”.

The two men’s’ words of integrity echo the philosophy and ideals held by Yanmar.

Related information

  • Find out more about how ORACLE TEAM USA, the America’s Cup and Yanmar not only believe in a sustainable future, but are working actively toward its realization.

    Find out more about how ORACLE TEAM USA, the America’s Cup and Yanmar not only believe in a sustainable future, but are working actively toward its realization.

    More Details