“Looking confused when seeing the ‘NT’ on the engine nameplate or parts list?” What on earth does this letter represent? Many truck drivers and maintenance workers have encountered such a problem: they want to replace parts for a Cummins 855 engine, but they fall into a trap because they don’t understand the meaning of “NT” – either the piston model is incorrect or the cylinder assembly doesn’t fit, wasting money and delaying the project schedule. What’s even more troublesome is that one can’t tell whether their engine is an “old model” or a “new one”, and even has no idea about its horsepower and torque. When communicating with parts suppliers, misunderstandings often arise due to unclear descriptions.

Don’t worry! This article will thoroughly solve the mystery of “NT”, enabling you to accurately identify the engine model, avoid purchasing the wrong parts, and have a clearer understanding of the true performance of the equipment.

NT855 Cummins

The Definite Answer To “NT“

“NT” is a key prefix in Cummins engine models, representing “New Technology” or “New Torque”. It is not an independent engine series but a major upgraded version of the classic Cummins 855 engine.

In a nutshell: When you see “NT855”, it means that this is a newer, more powerful and technologically advanced engine than the previous 855 model.

Why Is “NT” Crucial To You?

1. Part compatibility is the lifeline!

Serious warning: The NT855 is not compatible with the vast majority of parts of older non-NT 855 models (such as Big Cam IV)! There was once a truck driver who bought a cylinder liner marked “Suitable for 855” to save money. However, when he installed it on the NT855, he found that the cylinder interface design was different and had to scrap it and buy a new one.

The key differentiating components include

• Cylinder block/Cylinder liner: The cylinder block structure of the NT855 has been strengthened, and the cooling system has been optimized. The size and waterway design are different from the previous model.
• Piston/connecting rod: Redesigned to withstand higher burst pressure, with differences in the shape of the piston top and the length of the connecting rod;
• Cylinder head/valve mechanism: The layout of the intake and exhaust channels is optimized, and the valve spring and rocker arm structures are different.
• Fuel system: It is often equipped with the more advanced “N” series fuel injectors/pumps, which do not match the fuel injection pressure and injection Angle of the older model.
• Solution : When purchasing parts, must recognize the products marked “Suitable for NT855“. Just looking at “855” may very likely lead to a trap!

2. It is of great significance to performance!

The upgrade of NT855 is not only technical but also directly affects the user experience of your device:

• Stronger power: Compared with the old model 855, the horsepower (HP) and torque (Nm) of the NT855 usually increase by 10%-15%. For example, a certain model NT855 can reach 350 horsepower, while the old Big Cam IV might only have 300 horsepower.
• Higher efficiency: Improved fuel economy, with fuel consumption possibly reduced by 1-2 liters per 100 kilometers, making long-term operating costs more cost-effective.
• Better emissions: In the era when it was launched (such as the 1980s and 1990s), the NT855 met the stricter emission regulations at that time and was more environmentally friendly than its predecessor.

3. Don’t mistake the engine any more!

How to identify NT855 with the naked eye? Three key characteristics:

• Rocker arm cover: This is the most intuitive sign – The rocker arm cover of the NT855 is mostly a flat rectangle (the old Big Cam was often circular dome-shaped);
• Casting mark of the cylinder block: Carefully inspect the side of the cylinder block. There may be the word “NT” cast on it.
• Nameplate information: The engine nameplate (usually at the front or side of the cylinder block) clearly indicates the model number “NT855” and comes with a serial number (ESN).

No matter what the appearance is like, the engine serial number (ESN) is the “ID card”. When ordering parts or inquiring about technical information, providing a complete ESN is the most reliable way to avoid errors. |

The Action Steps You Must Take (A Guide To Avoiding Pitfalls)

1.The Golden Rule: Hold onto the Engine Serial Number (ESN) tightly!

Whether you consult online or purchase parts offline, we will provide the complete ESN (usually consisting of 14 to 17 letters and numbers) at the first time. Parts suppliers can precisely match parts through ESN.

2. Visual inspection double insurance:

Lift the hood and check if the rocker arm hood is a flat rectangle.

Wipe the side of the cylinder body clean with a cloth and look for the “NT” casting mark or the words “NT855” on the nameplate.

3. Be clear about “identity” when communicating:

When communicating with repair shops or parts suppliers, be sure to say “My engine is NT855” instead of simply saying “855”. There was once a user who mistakenly bought the valve spring of Big Cam because he forgot to say “NT”, resulting in abnormal noises from the engine.

4. For data inquiries, please recognize “NT” :

When downloading the maintenance manual or checking the parts catalogue, choose the version marked “NT855 Exclusive” to avoid being misled by the general information.

5. Be vigilant against the “generic” trap:

When you see a part marked “suitable for 855 series”, be sure to ask if it includes NT855. If necessary, ask the merchant to provide a list of compatible models to reduce risks.

Conclusion: Master “NT” And Take The Initiative

“NT” is not just two letters; it is a symbol of “new technology” and “new torque” – it represents a more powerful and reliable Cummins 855 engine. Understanding the meaning of “NT”, you will:

1. Accurately identify the equipment model and bid farewell to “confused maintenance”;
2. Completely avoid the risk of mismatched parts and save real money.
3. Having a clear understanding of the upper limit of power makes choosing a vehicle and loading more reasonable.
4. Zero communication barriers make maintenance and parts procurement more efficient.

The next time you see “NT855”, you will no longer be confused. Only by having a clear understanding can you keep your engine in the best condition all the time and ensure the smooth operation of your transportation or engineering tasks!

Cummins NT855 Engine | 240-450hp (179-336kW)