Chevrolet 1977 light duty truck, Service Manual

Page: 469 / 861

1.
Pressure Regulator 6. Cover Gasket
Valve 7.
Idler Gear
2.
Pressure Regulator
8. Drive Gear and Shaft
Spring
9.
Pump Body
3. Retaining Pin
10. Pickup Screen and
4. Screws
Pipe
5.
Pump Cover
Fig. 6A-47--0il Pump (L6 Exploded)
4. If the pickup screen an d pipe assembly need
replacing, m ount the p u m p in a soft-jawed vise and
extract pipe from pump.
CAUTIO N: Do not disturb the pickup screen on
the pipe. This is serviced as an assembly.
Cleaning and Inspection
1. W ash all parts in cleaning solvent and dry with
compressed air.
2. Inspect the p u m p body and cover for cracks or
excessive wear.
3. Inspect p u m p gears for d a m a g e or excessive
wear.
4. Check the drive g ear shaft for looseness in the
p u m p body.
5. Inspect inside o f p u m p cover for w ear that
would perm it oil to leak past the ends o f the gears.
6. Inspect the pickup screen and pipe assembly for
d a m a g e to screen, pipe or relief grommet.
7. Check the pressure regulator valve for fit.
NOTE: The p u m p gears and body are not serviced
separately. If the pum p gears or body are dam ag ed
or worn, replacem ent o f the entire oil p u m p
assembly is necessary.
Assembly
1. If the pickup screen and pipe assembly was
removed, it should be replaced with a new part. Loss o f
press fit condition could result in an air leak and loss o f
oil pressure. M ount the p u m p in a soft-jawed vice, apply
sealer to the end o f pipe and tap the pipe in place with a
plastic h a m m e r using Tool J-8369.
CAUTION:
Be careful o f twisting, shearing or
collapsing pipe while installing in pum p.
Pickup screen m ust be parallel to bottom o f oil
p a n when oil p u m p is installed.
2. Install the pressure regulator valve and related
parts.
3. Install the drive gear and shaft in the p u m p
body.
4. Install the idler gear in the pu m p body with the
smooth side o f gear towards p u m p cover opening.
5. Install the pum p, with new gasket, and torque
attaching screws to specifications.
6. T urn drive shaft by hand to check for smooth
operation.
C O N N E C T IN G ROD BEARINGS
Connecting rod bearings are o f the precision insert
type and do not utilize shims for adjustm ent. DO N O T
FILE RODS O R R O D CAPS. If clearances are found to
be excessive a new bearing will be required. Bearings are
available in standard size and .001" and .002" undersize
for use with new and used standard size crankshafts, and
in .010" and .020" undersize for use with reconditioned
crankshafts.
Inspection and Replacement
1. With oil p a n and oil p u m p removed, remove the
connecting rod cap and bearing.
2. Inspect the bearings for evidence o f w ear or
dam age. (Bearings showing the above should not be
installed.)
3. W ipe the bearings and cran k p in clean o f oil.
4. Measure the crankpin for out-of-round or tap er
with a micrometer. If not within specifications replace or
recondition the cranksahft. If within specifications and a
new bearing is to be installed, measure the m axim um
d iam eter o f the crankpin to determ ine new bearing size
required.
5. If within specifications m easure new or used
bearing clearances with Plastigage or its equivalent.
NOTE: If a bearing is being fitted to an out-of-
round crankpin, be sure to fit to the m axim um
d iam eter o f the crankpin. If the bearing is fitted to