BMW F87 M2 Engine Piston Header 3.0 Petrol N55 8629946

BMW F87 M2 Engine Piston Header 3.0 Petrol N55 is an original component from the Pistons and rings group, designed for a petrol-powered engine unit. Thanks to its factory origin from the BMW range, this component ensures a precise fit for the N55 engine architecture and maintains the operating parameters specified by the manufacturer.

Specifications and technical data

• SKU: 8629946-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 8629946
• Fuel type: Petrol
• Part type: Piston
• Category: Pistons & Rings

Purpose and function in the BMW 3.0 petrol N55 engine

The piston in a petrol engine is responsible for converting the energy of the fuel-air mixture combustion into mechanical motion, which is why its geometry, mass, and material must be precisely matched to the specific unit. In the case of the N55 engine, using a dedicated piston allows for maintaining the correct compression ratio, stable operation at high RPMs, and proper thermal parameters.

The original piston from the BMW family, used in the F87 M2 model, has been designed to withstand the loads characteristic of powerful, turbocharged petrol engines. The appropriate shape of the piston crown, guidance in the cylinder liner, and cooperation with piston rings reduce oil consumption and help maintain uniform pressure in the cylinders.

Benefits of using an original BMW piston

Using a piston from the same design family as the engine unit brings a number of practical service and operational benefits:

• maintaining factory engine operating parameters under loads typical for the BMW F87 M2,
• proper cooperation with the crankshaft-piston system and the cylinder head,
• adequate heat dissipation from the combustion chamber in a petrol engine,
• reducing the risk of improper fitment in the cylinder compared to universal aftermarket replacements.

For units powered by petrol fuel, it is crucial to maintain proper combustion chamber sealing and stable operation at high temperatures. The piston from the Pistons and rings group dedicated to the N55 supports these requirements, which translates into engine refinement and consistent performance.

Condition, selection, and service application

The component comes from the BMW range and is intended for service applications in the 3.0 petrol N55 engine, including repairs after mechanical damage, partial overhauls, or when replacing individual cylinders. When selecting a piston, it is recommended to:

• compare the design with the element currently installed in the engine,
• check the cylinder diameter and the condition of the liner before installation,
• use new piston rings matched to the same dimensional group.

A properly selected piston helps restore uniform compression pressure between cylinders, which is important for both power and the operation of engine control systems. This is particularly significant in modern petrol units, where combustion parameters are strictly monitored by electronics.

Complementary elements from the BMW Pistons and rings group

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other elements from the same group, such as additional pistons, piston rings, or compatible gudgeon pins, check the available parts in the BMW Pistons and rings category.

Technical support and service knowledge

For major repair work within the drivetrain, it is also worth paying attention to selecting the right gearbox for the engine's characteristics. To deepen your knowledge regarding typical transmission failures and the principles of purchasing used components, you can use the advice contained in the article Gearbox: manual, automatic, or DSG – typical failures and a guide to buying a used gearbox, which helps in better planning comprehensive work on the drivetrain.