bgott
Veteran Member
There is a couple of reasons they used babbit as a bearing material. One is that it is softer than the crank. Another is embedability. Those old engines didn't run full flow oil filters, if they had one at all it was a bypass filter. That means the only oil it filtered was oil bypassing the pressure relief valve on it's way back to the sump. With no oil filtration you ended up with some good sized chunks of trash in the oil. With soft babbit bearings the junk would be pushed down into the bearing material rather than being held up where it could groove the crank.