BMW 3 Series E90 320si Petrol N45 Engine Crankshaft Crank Shaft N45B20A

BMW 3 Series E90 320si Petrol N45 Engine Crankshaft Crank Shaft is an original component from the Crankshafts group, designed for the N45B20A petrol engine. Using a crankshaft of this type allows for a technically correct engine rebuild while maintaining the factory performance parameters and characteristics of the power unit.

Specifications and technical data

• SKU: 7541302
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7541302
• Substitutable numbers: 11217541302, 7541302, ŁS
• Fuel type: Petrol
• Category: Crankshafts

Purpose and compatibility

The presented crankshaft is dedicated to the N45B20A engine used in the BMW 3 Series E90 320si petrol model. Using a component from the same design family ensures proper fitment with the engine block, bearings, and the piston-connecting rod assembly, which translates into stable operation of the unit across the entire rev range.

By maintaining the original geometry of the crankshaft, it is possible to preserve the correct balance of the system, which limits vibrations, reduces loads on the main and connecting rod bearings, and promotes smooth operation of the petrol engine.

Technical characteristics of the crankshaft

The crankshaft from this series has been designed with the specific characteristics of the sporty 320si variant in mind, with an emphasis on precision at higher rotational speeds. The design provides for an appropriate arrangement of main and connecting rod journals, oil channels, and surfaces interacting with the bearings, which enables the maintenance of stable oil pressure and effective lubrication under load.

Selecting the correct crankshaft for the N45B20A petrol engine is crucial for:

• maintaining correct compression and uniform cylinder operation,
• preserving the factory operating culture of the power unit,
• reducing the risk of damage to bearings and connecting rods,
• proper cooperation with the ignition system and engine management.

Application in engine repair and rebuild

The used crankshaft for the BMW 3 Series E90 320si is suitable for major overhauls, replacing a damaged crankshaft after seizure, or restoring the N45B20A unit to its stock parameters. Using an original component from the Crankshafts group allows for compliance with factory service documentation and the manufacturer's assembly procedures.

When selecting a crankshaft, it is worth paying attention to:

• compatibility with the specific version of the petrol engine,
• selection of appropriate main and connecting rod bearings,
• correct tightening procedure for main cap and connecting rod bolts,
• checking clearances and alignment after installation in the block.

Condition and benefits of choosing an original used component

The item is offered as a used part, which represents a reasonable compromise between repair costs and maintaining the original technical specification. Choosing an original crankshaft from dismantling allows for the preservation of factory material quality and processing technology, which are difficult to replicate in aftermarket replacements of unknown origin.

In practice, this translates into:

• better predictability of engine behavior after an overhaul,
• easier matching to the existing piston-connecting rod assembly,
• the ability to use factory BMW service data during assembly.

Related components and further system expansion

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 other shafts, components interacting with the crankshaft system, or parts for engine overhaul, check the available parts in the BMW Crankshafts category.

When planning broader service work, it is also worth familiarizing yourself with practical tips regarding the safe selection of components from the secondary market – the article Second-hand braking system: how to safely choose discs, calipers, and ABS? may be helpful, as it discusses universal principles for assessing used components in the context of safety and quality.