GMC T Series 1994 Repair Manual page 535

Figure 45— Measuring the Ring End Gap
Figure 46— Checking Ring Fit
3. Measure the space or gap between the ends of
the ring with a feeler gage (figure 45).
4. Refer to " Specifications" in the proper section.
5. This gap measurement applies to a new ring
used in a new bore for the service standard
piston. If a new ring is being used in a worn
bore, the end gap may be slightly more that
specifications.
* Assemble (Figure 46)
• Piston rings. Refer to the instructions furnished with
the parts package.
• While assembling rings onto piston rotate rings to
check for binding. If binding occurs inspect ring
grooves for dirt or damage, such as nicks caused
by improper installation (figure 46).
t j | Measure (Figure 47)
• Ring clearance. Use a feeler gage as shown in
figure 47. Compare with specifications at the rear
of this section.
B4979
Figure 47— Measuring Ring Clearance
INTAKE AND EXHAUST
Clean
• Old pieces of gasket from the gasket surfaces.
• Soot deposits from the intake manifold.
L®
Inspect
• Manifolds for cracks, broken flanges, and gasket
surface damage.
Important
• Whenever the camshaft needs to be replaced, a
new set of hydraulic lifters must also be installed.
I ?
Inspect (Figure 26)
• Camshaft lobes and journals for scratches, pitting,
scoring, and wear.
• Thrust plate (91) for wear and scoring.
Measure (Figure 48)
• Camshaft journals. Use a micrometer (figure 48).
The proper journal dimensions are as follows:
• #5 (rear) journal: 50.975 to 51.025 mm (2.0069
to 2.0089 inches).
•A ll others: 54.975 to 55.025 mm (2.1644 to
2.1663 inches).
CAMSHAFT BEARINGS
1?
Inspect
Camshaft bearings for scratches, pits, or loose fit in
their bores. Replace the camshaft bearings if nec­
essary.
MANIFOLDS
CAM SHAFT