SERVICE MANUAL
CONNECTING RODS, PISTONS, RINGS & SLEEVES
Section 5
a.
After piston has been thoroughly cleaned, locate
the piston part number and engine model
number stamped on top of piston (See Fig. 17.)
IMPORTANT:
(Refer to Figure 18.)
•
Full keystone grooves use the 0.1150 in. gauge
pin to determine piston ring groove wear.
•
Half keystone grooves use the 0.0900 in. gauge
pin to determine piston ring groove wear.
•
Rectangular grooves DO NOT use gauge pins.
Use side clearance and ring gap dimensions to
determine piston ring groove wear.
b.
Select appropriate size gauge pins for groove being
measured (See Service Specification Chart for
piston ring groove widths).
c.
Place correct size gauge pin and spring
assembly in piston groove to be measured. BE
SURE THAT CENTER OF GAUGE PINS ALIGN
WITH CENTER OF PISTON SO GAUGE PINS
ARE PARALLEL. (See Fig. 19).
d.
Select correct size outside micrometer to
measure piston diameter over gauge pins as
follows:
Engine
Micrometer
Size
300 Series
3-4 in.
400 Series
4-5 in.
Figure 16. - Piston Groove Wear Measuring Tool (Tool No. 3020)
CGES-185-3
PRINTED IN UNITED STATES OF AMERICA
Page 17
