FUSO 4M4 – LUBRICATION – STRUCTURE AND OPERATION – Lubrication of Engine Components

• The engine oil in the main oil gallery lubricates the engine components in the following ways.

Main bearing and connecting rod bearing

Valve mechanism

• The engine oil flows from the main oil gallery to the oil passages in the cylinder head to lubricate every journal on the camshaft, and then returns to the oil pan.
• Engine oil flows from the cylinder head to the oil passages in the pivot bolt and the adjusting screw to lubricate the rocker arms and camshaft.

Check valves and oil jets

• An oil jet is fitted in the lower part of the subgallery for each cylinder.
• Engine oil is sprayed out of the oil jet into the piston to cool the piston.
• Each oil jet is fitted with a check valve that opens and closes at predetermined oil pressure levels. At low engine speeds, the check valve closes to maintain the required volume of oil in the lubrication system and prevent reductions in oil pressure.

Vacuum pump

• Engine oil flows to the vacuum pump through the oil pipe to lubricate the pump vanes.
• The used engine oil is discharged from the oil outlet port and returns to the oil pan.

Idler shaft

• The idler sprocket bushing is lubricated by the engine oil fed through the oil passage in the idler shaft.

Timing chain

• The timing chain is lubricated by the engine oil spouted from the oil injection hole of the oil jet fitted to the idler shaft.

Turbocharger

• Engine oil is fed to the bearing housing from the main oil gallery through the oil pipe to lubricate the inside of the turbocharger.
• The piston rings, which are installed on both sides of the turbine wheel shaft, serve as oil seals.

 

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