What does the '+0.25' size mean for these main bearings?

The '+0.25' indicates that these bearings are 0.25mm larger in diameter than standard size. They are intended for use when the engine's crankshaft journals have been machined down by 0.25mm to remove wear or imperfections.

What type of engine is this bearing set best suited for?

This bearing set uses a lead-free composite material and bi-metal aluminum construction, making it ideal for engines that operate under low to medium loads. It's a well-built option for many BMW applications.

Does this main bearing set come with all the necessary components for installation?

This listing is for the main bearing set only. It is recommended to consult the manufacturer's installation instructions or a professional mechanic to ensure you have all other necessary components and supplies for a complete engine rebuild.

Specifications

Brand: King Engine Bearings
Part #: MB7039AM0.25
UPC: 611500387470

King Engine Bearings BMW M51/M57 (Size +0.25) Main Bearing Set

Name: King Engine Bearings BMW M51/M57 (Size +0.25) Main Bearing Set
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-bmw-m51-m57-size-0-25-main-bearing-set-t14-132701
Price: 130.46 USD
Availability: BackOrder

$130.46

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King Engine Bearings BMW M51/M57 main bearing set, size +0.25. A well-built option for engine rebuilds.

Key Features

Fits a wide range of BMW vehicles including 323Ci, 525i, and Z4 models.
Main bearing set sized at +0.25mm for use with machined crankshaft journals.
Constructed with a lead-free, environmentally safe composite material.
Features a bi-metal aluminum construction suitable for low to medium-load engines.
Specializes in engine bearings, with a focus on supplying well-built components.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

If you're rebuilding the engine in your BMW, these main bearings from King Engine Bearings are a solid option. They are specifically sized at +0.25mm, meaning they are designed to be used when the crankshaft journals have been machined down by 0.25mm to clean up wear or damage. King has been specializing in bearings since 1960, focusing on supplying well-built engine bearings for a wide range of applications.

This particular set uses a lead-free composite material that's environmentally safe and works well in engines that don't see extremely heavy loads. The bi-metal aluminum construction offers good performance for applications like the BMW 323i, 525i, or Z3 models. These bearings are designed to fit right and perform as expected during the critical break-in period and beyond.