Oil for the rocker arms comes from the oil manifold
will let the oil go around the oil cooler (6) when the oil is
(3) through passages in the cylinder block. The passages
cold or if the restriction in the oil cooler is more than the
in the cylinder block are in alignment with a passage in
other parts of the system. A difference in pressure of 12
each cylinder head.
to 15 psi (0.8 to 1.1 kg/cm2) between the oil inlet and the
oil outlet will open the bypass valve.
The passage to the cylinder head on the left side is
near the front of the cylinder block. The passage to the
There are two pressure outlets in the base for the oil
cylinder head on the right side is near the rear of the
cooler. The pressure outlets are on the outlet side of the
oil cooler and oil filters. The pressure outlets are for the
sending unit and switch for the oil pressure.
The passage in each cylinder head sends the oil into
an oil hole in the bottom of the mounting surface of the
Oil from the oil filters (12) goes through a passage in
bracket that holds the shaft for the rocker arms. The oil
the cylinder block to oil manifold (3). The oil manifold is in
hole is in the front bracket on the left side and in the rear
the center of the cylinder block above the camshaft and
bracket on the right side. The oil then goes up through
goes the full length of the cylinder block. Oil goes from
the bracket and into the center of the shaft for the rocker
the oil manifold to the bearings for the camshaft. There
arms. Oil goes along the center of the shaft to the
are grooves in the bore in the cylinder block around the
bearings for the rocker arms. From the rocker arms the
The bearing surfaces
oil is pushed through small holes to give lubrication to the
(journals) on the camshaft get lubrication from these
valves push rods cam followers and camshaft lobes.
grooves through a hole in the bearings for the camshaft.
After the lubrication oil has done its work it will return to
Some of the oil goes around the grooves and down
the oil pan for the engine.
through a passage to a hole and groove in the top half of
the main bearing. Oil from the hole and groove gives
lubrication to the bearing surfaces (journals) of the
NOTE: On marine engines the location of the oil cooler
crankshaft for the main bearings.
for the marine gear is on top of the flywheel housing.
Oil gets into the crankshaft through holes in the
bearing surfaces (journals) for the main bearings.
Passages connect each bearing surface (journal) for the
main bearing with the bearing surface (journal) for the
connecting rod next to it. The piston pins get lubrication
from oil thrown by other parts.