Bearings babbitt or brass

[Guest Rick001]

I'm building a 1908 Buick model 10 engine. Does anyone know why you can't machine brass beearings as opposed to having babbitt poured. Strength, Longevity, etc. Your expertise is appreciated. Thanking you in advance for your responses. Rick

[Guest BillP]

You may find brass is too weak to act as a bearing material. Bronze is a better alloy; stronger. If the bearings are running in the open, you might cut down bushings made of oil-lite, an oil impregnated bushing developed by Chrysler in the 20s-30s.

[Mark Shaw]

I got this from the Internet (author unknown) & condensed it for you:

Babbitt is a tin based alloy bearing material with two other primary elements; copper and antimony. Originally, Babbitt did not have ANY lead in it. But the name "Babbitt" soon became the generic name for any bearing material, & lead based bearing materials are now included in the term Babbitt.

Tin is a great metal for a bearing. It is soft, but not too soft. It will let dirt embed and it coats it so it will not score the shaft. If you run out of lubricant, the tin will melt some and liquid tin is a lubricant too. But it really is too soft to be used alone as a bearing in engines as it melts at too low a temperature (449* F)

Copper is used to make the tin harder. As the percentage of copper increases so does the melting point of the tin copper alloy. Copper melts at 1984* F.

Antimony also makes tin harder and increases its melting point. Antimony brings another unique property it shares with water. Antimony expands as it solidifies. Most metal shrinks as it cools. Shrinking means the bearing that was just poured will pull away from the block. Antimony melts at 1167* F.

Copper and antimony also affect the malleability of the alloy. They modify the proprieties of the tin and allow it to handle the impact force in the engine without cracking or become squished out like butter.

Draw your own conclusions, but for my money, tin Babbitt is the way to go. It is a good bearing material and will protect your crankshaft from being worn or scored.