Brass or stainless steel? That is the question.

Does anyone have an opinion on the brass liner shims that Cummins is using on the ISX? It seams to me that if the cast iron wears out, wouldn't brass which is softer, wear out also? I worked on one that was worn .010" into the cast iron, on the right side, causing the liner to be have .009" protrusion on the left side & .001" below the deck surface on the right side. Needless to say, it would not hold a head gasket. I think that they should be run at .014" protrusion, which holds the liner tight, preventing it from moving around and wearing the counterbore surface. I am finding that the ones that are at .009"-.010" protrusion are the ones that wear out the counterbore. In my opinion, you should have the person that is cutting your counterbores, cut them for 1 stainless steel shim, and remove the brass shim from the liner, to give them .014" protrusion. Any comments?

 

I know that the early ones had trouble with the block warping all over the place. These are late model engines that I am working on. I think that the reason that these are wearing, is because the thrust of the piston firing is pushing the liner in an out on the right side. This sliding is causing the cast iron to wear away, thus the liner starts to sink on the right side. If it was clamped tighter, it could not move in & out.