Cylinder Block, Liners, Pistons and Rods
CHECK PISTON RING GROOVE WEAR
Pistons with tapered rods will use JDE62 Ring Groove
Wear Gauge and pistons with straight rods will use
JDG957 Ring Groove Wear Gauge.
1. Use the appropriate ring groove wear gauge (C) to
check wear of keystone ring groove (top groove).
Check grooves at several locations around the
circumference of piston.
Gauge shoulders should not contact ring land.
Clearance (D) between shoulders of tool and ring land
indicate ring groove is good.
If ring groove is worn, replace piston and liner as a
matched set. If ring groove is good, proceed to next
A--Piston with Good Keystone Ring Groove
B--Piston with Worn Keystone Ring Groove
C--Ring Groove Wear Gauge
E--No Clearance (Replace)
2. Check second and third ring grooves using a new
piston ring and a feeler gauge. Measure clearance at
several points. Compare measurements with
Piston Ring-to-Groove Clearance--New Piston Ring (Second and
Third Ring Grooves)--Specification
Maximum Clearance................................................... 0.20 mm (0.008 in.)
3. Replace piston and liner (as a set) if clearance