Well, the problem is, "surface" rust doesn't grow on the surface, it is oxygen that combined with metal, is porous and occupies more space, and therefore sticks above the original surface of the metal over what is a pit. This is the way it is on a magnified level. The question is, will the oil film remain intact over the pits, and is there enough "high metal" between the pits to carry the load, until such time as the whole thing evens out from wear? only a "line" along the cam is actually in contact with the cam follower at any given moment during operation, and the pounds per square inch along that line are spectacular. The oil film sort of "floats" the cam on the cam follower. If the metal was actually touching, it wouldn't last, no matter what kind of metal it was.

IMO, lube it well (even with assembly lube), run it, look at it in a hundred miles, and if it's OK, forget about it. If not, there was nothing you could have done to "fix" it after it happened.

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

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