1991 1999 ford explorer chilton User Manual

INSPECTION
Now that the engine block and all of its components are clean, its time to inspect them for wear and/or
damage. To accurately inspect them, you will need some specialized tools:
Two or three separate micrometers to measure the pistons and crankshaft journals
· 
A dial indicator
· 
Telescoping gauges for the cylinder bores
· 
A rod alignment fixture to check for bent connecting rods
· 
If you do not have access to the proper tools, you may want to bring the components to a shop that does....

Use a telescoping gauge to measure the cylinder bore diameter-take several readings within the
same bore
The amount of cylinder wall wear is always greater at the top of the cylinder than at the bottom. This wear is
known as taper. Any cylinder that has a taper of 0.0012 in. (0.305mm) or more, must be rebored.
Measurements are taken at a number of positions in each cylinder: at the top, middle and bottom and at two
points at each position; that is, at a point 90 degrees from the crankshaft centerline, as...

Crankshaft
Inspect the crankshaft for visible signs of wear or damage. All of the journals should be perfectly round and
smooth. Slight scores are normal for a used crankshaft, but you should hardly feel them with your fingernail.
When measuring the crankshaft with a micrometer, you will take readings at the front and rear of each journal,
then turn the micrometer 90 degrees and take two more readings, front and rear. The difference between the
front-to-rear readings is the journal taper and the...

CONNECTING ROD
You should have the connecting rod checked for straightness at a machine shop. If the connecting rod is bent,
it will unevenly wear the bearing and piston, as well as place greater stress on these components. Any bent or
twisted connecting rods must be replaced. If the rods are straight and the wrist pin clearance is within
specifications, then only the bearing end of the rod need be checked. Place the connecting rod into a vice, with
the bearing inserts in place, install the cap to the...

Use a ball type cylinder hone to remove any glaze and provide a new surface for seating the
piston rings
Pistons and Connecting Rods
Only pistons with the wrist pin retained by C-clips are serviceable by the home-mechanic. Press fit pistons
require special presses and/or heaters to remove/install the connecting rod and should only be performed by a
machine shop.
All pistons will have a mark indicating the direction to the front of the engine and the must be installed into
the engine in that manner....

Varnish build-up or C-clip groove burrs may increase the difficulty of removing the wrist pin. If
necessary, use a punch or drift to carefully tap the wrist pin out.
Insure that the wrist pin bushing in the connecting rod is usable, and lubricate it with assembly lube.
3. 
Remove the wrist pin from the new piston and lubricate the pin bores on the piston.
4. 
Align the forward marks on the piston and the connecting rod and install the wrist pin.
5. 
The new C-clips will have a flat and a rounded side to...

Apply a strip of gauging material to the bearing journal, then install and torque the cap
Install cap and tighten bolts to specifications. Do not turn crankshaft while Plastigage® is in
place.
2. 
Remove the cap. Using the supplied Plastigage® scale, check width of Plastigage® at widest
point to get maximum clearance. Difference between readings is taper of journal.
3.  HOW TO USE THIS BOOK
ASSEMBLY 481 

After the cap is removed again, use the scale supplied with the gauging material to check the
clearance
If clearance exceeds specified limits, try a 0.001 in. or 0.002 in. undersize bearing in
combination with the standard bearing. Bearing clearance must be within specified limits. If
standard and 0.002 in. undersize bearing does not bring clearance within desired limits,
refinish crankshaft journal, then install undersize bearings.
4. 
After the bearings have been fitted, apply a light coat of engine...

Mount a dial gauge to the engine block and position the tip of the gauge to read from the crankshaft
end.
1. 
Carefully pry the crankshaft toward the rear of the engine and hold it there while you zero the gauge.
Carefully pry the crankshaft back and forth while reading the dial gauge for end-play
2. 
Carefully pry the crankshaft toward the front of the engine and read the gauge.
3. 
Confirm that the reading is within specifications. If not, install a new thrust bearing and repeat the
procedure. If the...

Checking the piston ring-to-ring groove side clearance using the ring and a feeler gauge
Check the ring side clearance of the compression rings with a feeler gauge inserted between
the ring and its lower land according to specification. The gauge should slide freely around
the entire ring circumference without binding. Any wear that occurs will form a step at the
inner portion of the lower land. If the lower lands have high steps, the piston should be
replaced.
The notch on the side of the bearing cap...