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

The +0.25mm sizing indicates that these bearings are designed for a crankshaft that has been machined down by 0.25mm. This is common when rebuilding an engine to ensure a proper fit and clearance with worn or resurfaced crankshaft journals.

What is the advantage of the bi-metal aluminum material?

The bi-metal aluminum construction offers a good balance of strength and conformability, which is ideal for the load conditions typically found in low to medium-load engines. This material helps to maintain proper oil film and reduce friction.

Are these bearings compatible with all 4Zb1 engines?

These main bearings are specifically designed for the 4Zb1 engine and are verified to fit the listed Isuzu models and years. Always confirm your engine code and vehicle fitment before purchasing.

Specifications

Brand: King Engine Bearings
Part #: MB5559AM1.25
UPC: 611500387265

King Engine Bearings Isuzu 4Zb1 (Size +0.25mm) Main Bearing Set

Name: King Engine Bearings Isuzu 4Zb1 (Size +0.25mm) Main Bearing Set
Brand: King Engine Bearings
SKU: king-engine-bearings-king-engine-bearings-isuzu-4zb1-size-0-25mm-main-bearing-se-t14-770833
Price: 50.12 USD
Availability: BackOrder

$50.12

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Fits 1986-1995 Isuzu Pickup. King Engine Bearings main bearing set for the 4Zb1 engine, sized +0.25mm. Built for reliable engine performance.

Key Features

Fits 1986-1995 Isuzu Pickup, 1989-1993 Amigo, 1985-1989 Impulse, and 1986-1987 Trooper.
Main bearing set for the Isuzu 4Zb1 engine.
Size is +0.25mm, intended for a machined crankshaft.
Constructed from a bi-metal aluminum material.
Features a lead-free composite for environmentally safe operation.
Suitable for low to medium-load engine applications.

⚠️ 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

This is a set of main bearings from King Engine Bearings, specifically for the 4Zb1 engine found in your 1986-1995 Isuzu Pickup, Amigo, Impulse, or Trooper. Main bearings are crucial components that support the crankshaft within the engine block, allowing it to spin smoothly while handling significant loads. This set is sized +0.25mm, meaning it's intended for crankshafts that have been machined to that specific undersize.

King Engine Bearings specializes in creating durable engine bearings. These particular main bearings are constructed from a bi-metal aluminum material, which is a solid choice for low to medium-load engines like those in your Isuzu. They also feature a lead-free composite, making them an environmentally safer option. This construction helps ensure consistent performance and longevity for your engine's rotating assembly.