Dodge RAM TRUCK 1500 1995 Service Manual page 881

B R 3 J L ENGINE 9 - 37
LUBRICATION S Y S T E M
A gear—type positive displacement pump is
mounted at the underside of the rear main bearing
cap. The pump draws oil through the screen and in­
let tube from the sump at the rear of the oil pan. The
oil is driven between the drive and Idler gears and
pump body, then forced through the outlet to the
block. An. oil gallery In the block channels the oil to
the Inlet side of the full flow oil filter. After passing
through the filter 'element, the oil passes from the
center outlet of the filter through an oil gallery that
channels the oil up to the main gallery which ex­
tends the entire length on the right side of the block.
The oil then goes down to the No. 1 main bearing,
back up to the left side of the block and Into the oil
gallery on the left side of the engine.
Galleries extend downward from the main oil gal­
lery to the upper shell of each main bearing. The
crankshaft is drilled Internally to pass oil from the
main bearing journals to the connecting rod journals.
Each connecting rod bearing has half a hole in it, oil
passes through the hole when the rods rotate and the
hole lines up, oil is then thrown off as the rod ro­
tates. This oil throwoff lubricates the camshaft lobes,
distributor drive gear, cylinder walls, and piston
pins.
The hydraulic valve tappets receive oil directly
from the main oil gallery. The camshaft bearings re­
ceive oil from the main bearing galleries. The front
camshaft bearing journal passes oil through the cam­
shaft sprocket to the timing chain. Oil drains back to
the oil pan under the number one main bearing cap.
The oil supply for the rocker arms and bridged
pivot assemblies is provided by the hydraulic valve
tappets which pass oil through hollow push rods to a
hole In the corresponding rocker arm. Oil from the
rocker arm lubricates the valve train components.
The oil then passes down through the push rod guide
holes, and the oil drain back passages in the cylinder
head past the valve tappet area, and returns to the
oil pan.