The lubrication system consists of the following components:
- Oil pump
- Pressure regulator valve
- Pressure relief valve
- Oil filters
- Oil filter adaptor
- Oil cooler
- Oil level dipstick
- Oil pan
- Ventilating system
Oil leaving the pump is forced through the full-flow filters to the oil cooler and bypass passage and then into the oil gallery in the cylinder block. From there the oil is distributed to the various engine bearings and moving parts. Prior to 1993, a bypass type, spin-on filter was used in addition to the two full-flow oil filters. A portion of the oil is continually fed through the bypass filter and returned to the engine oil pan. Drains from the cylinder head and other engine parts return oil back to the oil pan.
Oil from the cooler is directed to a longitudinal main oil gallery on the cooler side of the cylinder block. This gallery distributes the pressurized oil to the main bearings and to a horizontal, transverse passage at each end of the cylinder block. From each of these two horizontal passages, oil flows into two vertical bores (one at each end of the cylinder block) to vertical passages in the cylinder head.
These passages in the cylinder head deliver oil from the cylinder block to the No. 1 and 7 lower camshaft bearing saddles. From there, the oil is directed upward (through the enlarged stud hole) to the No. 1 and 7 upper camshaft bearing caps. A drilled passage in each of these caps exits at the rocker arm shaft seat area, where it indexes rocker arm bushings and intermediate upper camshaft bearings. Some of the oil supplied goes to the rocker arm camshaft follower, roller pin and bushing.
The rocker is also drilled to supply oil to the valve adjusting screw, valve button, retainer clip, intake and exhaust valve stems and the fuel injector follower. The No. 4 camshaft cap is Y drilled, forming an oil path connection between the front and rear rocker arm shafts, to ensure complete lubrication. The oil then drains through passages in the cylinder head and block, and back to the oil pan.
Oil for lubricating the connecting rod bearings, piston pins and for cooling the piston dome is provided through the drilled crankshaft from the adjacent forward main bearings.
