Cracked Rear Main

[raventrone]

A friend with an engine that was totally rebuilt 17,000 miles ago as part of a frame-off restoration has been trying to figure out the cause of an oil leak. This past weekend he removed a section of the rear Main and discovered that the Babbitt was compromised. He is not on the forums and asked me to post these images hoping that someone might have some insight to offer.

The first pic is showing the problem found just a few minutes after removing the 2 mounting nuts.

The second pic is showing the piece of babbitt stuck in one of the two passageways which feed the oil return tube. The tube was otherwise clear.

The third pic is showing the piece of babbitt once removed from the passageway after using a screw drive to pry it out. When It was lifted it out it made a snapping sound to dislodge from the bearing passageway where it was sitting.

Simply put, the questions are:

1. What would cause the condition found in pic #1?

2. Would a piece of babbitt this large covering one of half of the oil return tube oil entry port contribute to the shorter life of the main?

This gentleman is meticulous about caring for his engine to a degree that borders on obsession. He is in the process of pulling the engine.

Thank you.











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