To meet the demands of higher loads and operating temperatures in modern engines as well as the requirements imposed by high performance, babbitt has been replaced by an alloy of aluminum. Fatigue can be identified by craters in the bearing surface where sections of lining material have flaked out. When babbitt cam bearings are installed under these demanding conditions, the lining may extrude or fatigue. Babbitt is limited in its ability to survive under these conditions due to its relatively low strength. The trend in modern engines has been toward higher operating temperatures and higher valve train loads. As a bearing surface layer, babbitt possesses the desirable properties necessary to survive under adverse conditions such as foreign particle contamination, misalignment and marginal lubrication on start up. Babbitt is a soft slippery material made up primarily of lead and tin and is quite similar to solder. But the cam journals are the same as stock, so I don't know what gives.For many years, nearly all camshaft bearings were manufactured with a lining of babbitt. Is this a problem with Sealed power 1898M bearings? Do they run tight? I didnt get +/- because they werent spun, just worn, and I'm installing a new TSP 220r cam. We could scrape the bearing down, but with as tight as they are, I don't want to remove too much of the Babbitt material and find myself in the same position of having to replace them again before I would If they fit.

I figure some of this can be due to the Crush from installing them, but. No +/-) I noticed that the journals on the new cam bearings are 10 1000ths larger than the old cam bearings. So we mic'ed the old bearings to make sure they were the correct replacement (supposed to be direct replacement.

I'm in the process of rebuilding the engine, and we just finished cleaning up all the parts and started to put the cam bearings in so we can finish cleaning the block, and after test fitting the cam with only two bearings in, It damn near seizes in place and becomes hard to even remove, let alone turn. I drive a 2004 Chevy Avalanche base, 4x4, With the 5.3 LM7.

Ls1 cam bearings best