Originally Posted by ILUVMILS

The cost depends on what we find, once the cylinder heads are removed. In most cases, the piston rings are the only "hard parts" that need replacing. In this case, we do the job without removing the engine. We replace the rod bearings as well, since we've got them out, but they're usually in pretty good shape. Depending on mileage, we may also recommend replacing the valve stem seals as a pre-caution. It only adds a couple hundred dollars to an already large bill, but we leave the final decision up to the owner.

Occasionally, we find severe scoring of the cylinder walls. In this case, we replace the engine block, with pre-fitted pistons. The crankshaft and connecting rods are re-used. The rod, main, and thrust bearings must be replaced as well. Before we tear down any M112/113's though, we listen to it carefully. Sometimes, a slight knocking noise can be heard from the engine. It's not very noticeable, but it has a very distinct sound. Once you hear it, it's easily recognizable. This is the tell-tale sound made when the cylinder walls are scored. When we hear this noise, we inspect the cylinders with an articulated borescope. If we find cylinder wall damage, we can give the owner the bad news, but keep the diagnosis cost down.