GMC T Series 1994 Repair Manual page 305

HONING
1. When honing the cylinders, follow the hone manu­
facturer's recommendations for use, cleaning, and
lubrication during honing. Use only clean, sharp
stones of the proper grade for the amount of mate­
rial to be removed. Dull, dirty stones cut unevenly
and generate excessive heat. When using coarse
or medium grade stones, use care to leave suffi­
cien t metal so that all stone m arks may be
removed with the fine stones used for finishing to
provide proper clearance.
2. Occasionally, during the honing operation, the cyl­
inder bore should be thoroughly cleaned and the
piston selected for the individual cylinder checked
for correct fit.
3. When honing to eliminate taper in the cylinder,
make full strokes of the hone in the cylinder. Also
check measurement at the top, middle, and bottom
of the bore repeatedly.
NOTICE: Handle the pistons with care and do
not attempt to force them through the cylin­
der until the cylinder has been honed to the
correct size. The piston can be distorted
through careless handling.
4. When finish honing a cylinder bore to fit a piston,
move the hone up and down at a sufficient speed
to obtain very fine uniform surface finish marks in a
cross-hatch pattern at the specified angle.
• 2.2L: 45 degrees
• All others: 45 to 65 degrees
5. The finish marks should be clean but not sharp,
free from imbedded particles and torn or folded
metal.
6. By measuring the piston to be installed at the siz­
ing point specified in the proper section, and
adding the average of the clearance specification,
the finish hone cylinder measurement can be deter­
mined. It is important that both the block and piston
be measured at normal room temperature.
7. It is of the greatest importance that refinished cylin­
der bores are trued up to have less than the speci­
fied out-of-round or taper. Each bore must be final
honed to remove all stone or cutter marks and
provide a smooth surface.
8. Refer to " Specifications" in the proper section for
piston to bore clearance tolerances.
9. After final honing and before the piston is checked
for fit, clean the bores with hot water and deter­
gent. Scrub with a stiff bristle brush and rinse thor­
oughly with hot water. It is essential that a good
cleaning operation be performed. If any of the
abrasive material is allowed to remain in the cylin­
der bores, it will wear the new rings, cylinder bores,
and bearings lubricated by the contaminated oil.
After washing, the dry bore should be brushed
clean with a power-driven fiber brush.
10. P erm anently mark the piston for the cylinder to
which it has been fitted.
11. Apply clean engine oil to each bore to prevent rust­
ing.
PISTON AND CO NNECTING
ROD ASSEM BLIES
DISASSEMBLY
Disassemble (Figures 4, 5, and 6)
❖
Tools Required:
J 24086-B Piston Pin Remover and Installer
1. Piston rings. In most cases the rings should be dis­
carded and replaced with new ones at assembly.