Work vehicle engine with split-circuit lubrication system

An internal combustion engine for a work vehicle comprising:

• an engine block having a plurality of piston-cylinder arrangements;
• a valve head positioned above the engine block and at least in part containing a valve train;
• an engine oil sump positioned below the engine block;
• a pump unit fluidly connected to the engine oil sump to receive engine oil therefrom, the pump unit comprising:
• a first oil pump comprising a variable displacement pump;
• a second oil pump;
• a drive line mechanically coupled to the first oil pump and the second oil pump and that drives each of the first oil pump and the second oil pump;
• and
• a manifold that directs engine oil from the engine oil sump to the first oil pump and the second oil pump;
• a spray jet oil gallery fluidly coupled to the first oil pump to direct a first flow of engine oil to piston spray jets in the internal combustion engine;
• and
• a main oil gallery fluidly coupled to the second oil pump to direct a second flow of engine oil to one or more oiled engine components in the internal combustion engine;
• wherein each of the first oil pump and the second oil pump comprises a linear actuator port configured to receive an actuator therein that adjusts a flow rate of engine oil generated by a respective one of the first oil pump and the second oil pump.