What does the .005 inch (0.25mm) undersize mean for these bearings?

This means the bearings are slightly smaller than standard size. They are intended for use when the engine's crankshaft journals have been machined down by 0.005 inches to ensure a precise fit and proper oil clearance during an engine rebuild.

What type of engine applications are these bearings best suited for?

These bearings are designed for Subaru FA20 and Toyota 4U-GSE engines, which are often found in performance-oriented vehicles. The tri-metal construction helps manage the higher loads typically seen in these applications.

What is the benefit of the tri-metal material used by King Engine Bearings?

The tri-metal material is a layered construction that offers a good combination of strength and the ability to conform to the crankshaft surface. This helps to maintain consistent oil pressure and reduce wear on both the bearing and the crankshaft.

Specifications

Brand: King Engine Bearings
Part #: MB5799SI0.25
UPC: 611500620232

King Engine Bearings Subaru FA20/ Toyota 4U-GSE/ O/S Housing .005in (Size 0.25) Main Bearing Set

Name: King Engine Bearings Subaru FA20/ Toyota 4U-GSE/ O/S Housing .005in (Size 0.25) Main Bearing Set
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-subaru-fa20-toyota-4u-gse-o-s-housing--t14-432515
Price: 53.95 USD
Availability: BackOrder

$53.95

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King Engine Bearings Subaru FA20/Toyota 4U-GSE main bearing set. Size 0.25in undersize.

Key Features

Main bearing set for Subaru FA20 and Toyota 4U-GSE engines.
Features a .005 inch (0.25mm) undersize for use with reconditioned crankshafts.
Constructed with King's tri-metal material for a balance of strength and conformability.
Helps maintain oil pressure and reduce friction in performance engines.

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About this part

Product Details

These King Engine Bearings main bearings are built with a .005 inch (0.25mm) undersize, meaning they are designed to be used when the crankshaft journals have been machined down to match this specific size during an engine rebuild. They are intended for Subaru FA20 and Toyota 4U-GSE engines, which are common in performance applications. King uses a unique tri-metal material that offers a good balance of strength and conformability, helping to protect your crankshaft from wear.

The tri-metal construction is key here. It’s a layered material that allows the bearing to flex slightly and conform to the crankshaft surface, which is crucial for maintaining consistent oil pressure and reducing friction. This is especially important in performance engines where loads can be higher. The .005 inch undersize is a specific machining step that ensures a precise fit when the crankshaft has been reconditioned.