New Main Bearing Set (030) 3.9 4B/4BT Cummins. These bearings are .030 inches undersized. If you have ground your crankshaft .030 undersize, these bearings are what you need.

Change bearings when you take your engines apart. I am shocked at the number of engines I see with holes in the block and that problem started with a bearing going bad.

This set includes the one thrust bearing and upper and lower bearings.

This set fits the older 4BT 8v engines.

Scroll down for more detailed compatibility information.

Short Product Description:

3802013 Main Bearing Set

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