GMC 1989 Light Duty Truck Repair Manual page 345

Figure 18— Measuring Ring Clearance
T he oil c o n tro l rin g s are th re e p ie ce typ es,
consisting of two rails and an expander.
Expander.
Lower rail.
Upper rail.
Upper compression ring. Use J 25220 (figure 5).
Lower compression ring. Use J 25220 (figure 5).
Flex all rings to make sure the rings are free. If
binding occurs at any point the cause should be
determined. If binding is caused by the ring groove,
correct by dressing the groove with a fine cut file. If
binding is caused by a distorted ring, check a new
ring.
$
M easure (Figure 18)
Ring clearance. Use a feeler gage as shown in
figure 18. Compare with " Specifications'
the proper section.
Installing the Piston Rings
(6.2 L Engines)
• All compression rings are marked on the upper side
of the ring. When installing the compression rings,
make sure the MARKED SIDE IS TOWARD THE
TOP OF THE PISTON.
GENERAL ENGINE MECHANICAL 6A-11
The top compression ring is a keystone type.
The oil ring is a two-piece type, consisting of an
expander and a scraper ring.
1^, M easure (Figures 7 and 16)
Ring end gap as follows:
1. Select rings comparable in size to the piston
2. Slip the compression ring in the cylinder bore;
3. Measure the space or gap between the ends
4. R efer to " S p e c ific a tio n s " in th e p ro p e r
5. If the gap between the ends of the ring is not
B-05078
Inspect (Figure 17)
13
Ring fit as follows:
1. Fit each compression ring to the piston on
2. Slip the outer surface of the top and second
*
Assem ble
Piston rings. Refer to the instructions furnished with
the parts package.
M easure (Figure 18)
in
• Ring clearance. Use a feeler gage as shown in
figure 18. Compare with " Specifications" in the
proper section.
being used.
then press the ring down into the cylinder bore
about 7 mm (1 /4-inch) above ring travel. Be
sure the ring is square with the cylinder wall.
of the ring with a feeler gage (figure 16).
section.
as specified, remove the ring and try another
for fit.
which it is going to be used.
compression ring into the respective piston
ring groove (figure 17), to make sure that the
ring is free. If binding occurs at any point, the
cause should be determ ined. If binding is
caused by the ring groove, correct by dressing
the groove with a fine cut file. If the binding is
caused by a distorted ring, check a new ring.