The second phase of a complete engine overhaul involves deep block cleaning, checking cylinder liner protrusion, and installing new main bearings. Precision is key to ensuring the engine handles maximum PTO loads without overheating.

During this critical phase, technicians must use micrometers to measure the crankshaft journals to ensure they are perfectly round and within OEM factory tolerances. Any scoring, heat discoloration, or micro-cracking on the crank requires immediate machining or complete replacement. Furthermore, the installation of piston rings must be executed with specific ring-gap alignments (often offset by 120 degrees) to prevent blow-by gases from pressurizing the crankcase once the engine is reassembled and put back into the field under heavy draft loads. Failure to observe these microscopic tolerances will result in premature engine failure and massive oil consumption.