"Full pressure" usually refers to the engine having a drilled crankshaft, which pressurizes the rod bearings, instead of having Babbit bearings molded into the rods, spray nozzles, and a solid crankshaft with no oil passages. The rods are still technically "pressure-lubricated" by the dippers hitting the oil streams, but it's done externally. A bent spray nozzle will cause a rod bearing to burn at speeds above idle.
Jerry
