What does the +0.25mm sizing mean for these bearings?

The +0.25mm sizing indicates that these bearings are slightly larger than standard size. This is typically used when the crankshaft journals have been machined down by 0.25mm during an engine rebuild to ensure proper oil clearance and a snug fit.

What is the advantage of a bimetal aluminum silicon base material?

A bimetal construction with an aluminum silicon base offers a good combination of strength and the ability to conform to the crankshaft surface. This helps to absorb shock and maintain consistent oil film, contributing to engine longevity.

Are these bearings sold individually or as a set?

This product is a main bearing set, meaning it includes all the necessary main bearings required for a complete engine rebuild for the specified applications.

Specifications

Brand: King Engine Bearings
Part #: MB4073SI0.25
UPC: 611500471858

King Engine Bearings Audi Acz/Aah/Ack. Aej/Asn (Size +0.25mm) Main Bearing Set

Name: King Engine Bearings Audi Acz/Aah/Ack. Aej/Asn (Size +0.25mm) Main Bearing Set
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-audi-acz-aah-ack-aej-asn-size-0-25mm-m-t14-770344
Price: 116.15 USD
Availability: BackOrder

$116.15

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Fits 1997-2005 Audi A4. King Engine Bearings main bearing set, size +0.25mm, for ACZ/AAH/ACK/AEJ/ASN engines. Essential for engine rebuilds.

Key Features

Fits 1997-2005 Audi A4, 1998-1999 and 2002-2006 Audi A4 Quattro, 1998-2004 Audi A6, 1998-2004 Audi A6 Quattro, and 1998-2000 Volkswagen Passat.
Main bearing set sized at +0.25mm for specific engine applications.
Constructed with a bimetal aluminum silicon base for durability and conformability.
Designed for Audi engines with codes ACZ, AAH, ACK, AEJ, and ASN.

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About this part

Product Details

Built with a bimetal aluminum silicon base, this main bearing set from King Engine Bearings is specifically sized at +0.25mm, making it a key component for engine rebuilds on certain Audi and Volkswagen models. These bearings are critical for maintaining proper oil clearance between the crankshaft and the engine block, ensuring smooth operation and preventing premature wear.

The bimetal construction offers a good balance of strength and conformability, allowing the bearing to adapt to the crankshaft's surface while providing durable support. This set is designed to fit Audi engines with codes ACZ, AAH, ACK, AEJ, and ASN, as well as the Volkswagen Passat from the late 90s into the early 2000s. Proper installation is crucial, as these bearings are a precise fit and directly impact the engine's longevity and performance.