Valve Rocker Arm; Push Rods; Cylinder Block/Refinishing Cylinder Walls; Repairing Sand Holes Or Porous Engine Castings - Ford LSG 875 Service Manual

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BASIC ENGINE
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OVERHAUL (Continued) '
VALVE ROCKER ARM
If the pad at the valve end of the rocker arm
has a grooved radius, replace the rocker arm.
Do not attempt to true this surface by
grinding.
PUSH RODS
Following the procedures under Push Rod In-
spection, check the push rods for straightness.
If the runout exceeds the maximum limit at
any point, discard the rod.
Do not attempt to
straighten push rods.
CYLINDER BLOCK
REFINISHING CYLINDER WALLS
Honing is recommended for refinishing cylin-
der walls
only
when the walls have minor scuffs
or scratches, or for fitting pistons to the specified
clearance. The grade of hone to be used is de-
termined by the amount of metal to be removed.
Follow the instructions of the hone manufactur-
er. If coarse stones are used to start the honing
operation, leave enough material so that all
hone marks can be removed with the finishing
hone which is used to obtain the proper piston
clearance.
Cylinder wails that are severely marred and/or
worn beyond the specified limits should be re-
finished.
Before any cylinder is refinished, all
main bearing caps must be in place and
tightened to the proper torque so that the
crankshaft bearing bores will not become
distorted from the refinishing operation.
Refinish only the cylinder or cylinders that re-
quire it. All pistons are the same weight, both
standard and oversize; therefore, various sizes
of pistons can be used without upsetting engine
balance.
Refinish the cylinder with the most wear first
to determine the maximum oversize. If the cylin-
der will not clean up when refinished for the
maximum oversize piston recommended, re-
place the block.
Refinish the.. cylinder to within approximately
0.0015 inch of the required oversize diameter.
This will allow enough stock for the final step of
honing so that the correct surface finish and pat-
tern are obtained.
For the proper use of the refinishing equip-
ment, follow the instructions of the manufacturer.
Only experienced personnel should be allowed
to perform this work.
Use a motor-driven, spring pressure-type
hone at a speed of 300-500 rpm. Hones of grit
sizes 180-220 will normally provide the desired
bore surface finish of 1532 RMS. When honing
the cylinder bores, use a lubricant mixture of
equal parts of kerosene and SAE No. 20 motor
oil. Operate the hone in such a way as to pro-
duce a cross-hatch finish on the cylinder bore.
The cross-hatch pattern should be at an angle of
approximately 30 degrees to the cylinder bore. '
After the final operation in either of the two re-
finishing methods described and prior to check-
ing the piston fit, thoroughly clean and oil the
cylinder walls. Mark the pistons to correspond to
the cylinders in which they are to be installed.
When the refinishing of all cylinders that require
it has been completed and all pistons are fitted,
thoroughly clean the entire block and oil the cyl-
inder walls.
REPAIRING SAND HOLES OR POROUS
ENGINE CASTINGS
Porosity or sand hole(s) which will cause oil
seepage or leakage can occur with modern cast-
ing processes. A compete inspection of engine
and transmission should be made. If the leak is
attributed to the porous condition of the cylinder
block or sand hole(s), repairs can be made with
metallic plastic (Part No. C6AZ-19554-A).
Do
not repair cracks with this material.
Repairs
with this metallic plastic must be confined to
those cast iron engine component surfaces
where the inner wall surface is not exposed to
engine coolant pressure or oil pressure, for
example:
1. Cylinder block surfaces extending along the
length of the block, upward from the oil pan
rail to the cylinder water jacket but not in-
cluding machined areas.
2. Lower rear face of the cylinder block.
3. Intake manifold casting.
4. Cylinder head, along the rocker arm cover
gasket surface.