Piston: Testing and Inspection
PISTON INSPECTION1. Measure the outer diameter of each piston at right angle 90° to the piston pin, 10.0 mm (0.40 in) above the under of the piston.
^ If not within the specification, replace the piston, piston pin and snap ring as a single unit.
Standard piston outer diameter
88.965-88.995 mm (3.5026-3.5037 in)
2. Measure the piston-to-cylinder clearance.
^ If not within the specification, replace the piston, piston pin and snap ring as a single unit.
Standard clearance between piston and cylinder
0.025-0.045 mm (0.0010-0.0017 in)
Maximum clearance between piston and cylinder
0.11 mm (0.0043 in)
3. Measure the piston ring-to-ring groove clearance around the entire circumference.
^ If it exceeds the specification, replace the piston ring.
Standard clearance between piston ring and ring groove
Top: 0.04-0.08 mm (0.002-0.003 in)
Second: 0.03-0.07 mm (0.0012-0.0027 in)
Oil: 0.06-0.15 mm (0.003-0.005 in)
Maximum clearance between piston ring and ring groove
Top: 0.17 mm (0.0066 in)
Second, Oil: 0.15 mm (0.0059 in)
4. Insert the piston ring into the cylinder by hand and use the piston to push it to the bottom of the ring travel.
5. Measure each piston ring end gap with a feeler gauge.
^ If it exceeds the specification, replace the piston ring.
Standard piston ring end gap
Top: 0.16-0.26 mm (0.0063-0.010 in)
Second: 0.31-0.46 mm (0.013-0.018 in)
Oil (rail): 0.15-0.40 mm (0.006-0.015 in)
Maximum piston ring end gap
1.0 mm (0.039 in)