I am working on a Detroit DD15 that blew it's head gasket on #6 cylinder. When I checked it out, I found that the liner protrusion was at .005" (even with a new liner). I looked up the specification for liner protrusion, and found that the specification is .0055" to .0105". This trucker would like to turn the power up on his engine, but I am afraid that he will have more head gasket problems, if he does that. Does anyone know of a way to get the liner protrusion up to the high side of the spec, without removing the engine, and resurfacing the block deck? Does Detroit make shims or over length liners. As the counterbore is over 8", down in the block, I do not think that a counterbore cutter is made that will machine the counterbore that is that deep. It would have to be very accurate, as that is what controls the liner protrusion. I think that this would be neccesary, if a trucker wants to up the power considerably. Any help would be much appreciated. I have also seen some BADLY pitted counterbores on several of these engines.