If you are getting ready to commit to a costly overhaul, are you sure your investment will last? Have you recently overhauled your engine only to have your headgasket blow 6 months after you leave the shop? If the Counterbore ledge in your engine has any pitting, you could be at risk for a blown headgasket even if the overhaul was done properly. Before your engine is rebuilt, take the time to have your counterbore ledge inspected for damage or pitting before your mechanic puts the engine back together. Counterbore repairs are performed in chassis. The block does not need to be sent out for machining.
Detroit 60s with pitting along the counterbore ledge can be repaired two ways. Light pitting can be repaired by machining out the damage to the ledge and installing shims. Heavier damage requires more boring to the block and installation of a sleeve. With good cooling system maintenance it is possible for the engine to run another million miles.
Caterpillar blocks can be repaired by inserts. The ledge must be machined to the measure of the insert. Caterpillar inserts should last the life of the overhaul.
The Cummins ISX engine with damage to the ledge can only be repaired by using shims. The ledge must be machined to accept the shim. N14 or NH 855 engines can be repaired with counterbore sleeves or shims depending on the extent of ledge damage.
