Counter-bore tools and parts...

[ceff_by]

nice vid. If headgasket blown counterbores MUST be checked -- coolant pressure and blown gasket in 90% is consequence -- reason is bad counterbores (usually exhaust side) and\or head cracks. Wondering that many shops have no idea about liners fretting\moving issue, they just drop new gasket and replace bearings with the hammer.. Wtf. . Here is manual from cummins. Its easy way to see if liners need to be repaired even without actual measurement.