Piston and Piston Ring Inspection
Piston and Piston Ring InspectionPiston
Visual inspection
Inspect piston for cracks or other damages.
Damaged or faulty piston should be replaced.
Piston diameter
As indicated in figure, piston diameter should be measured at specified position "a" from piston skirt end in the direction perpendicular to piston pin.
Piston diameter specification
Standard size: 88.949 - 88.961 mm (3.5019 - 3.5024 in.)
Piston clearance
Measure cylinder bore diameter and piston diameter to find their difference called piston clearance. Piston clearance should be within specification. If it is out of specification, replace cylinder block, piston rings and/or pistons.
NOTE:
Cylinder bore diameters used here are measured in thrust direction at two positions.
Piston clearance
Standard: 0.031 - 0.059 mm (0.0012 - 0.0023 in.)
Ring groove clearance
Before checking, piston grooves must be clean, dry and free of carbon deposits.
Fit new piston ring (1) into piston groove, and measure clearance between ring and ring land by using thickness gauge (2). If clearance is out of limit, replace piston.
Ring groove clearance
Piston Ring
Piston ring end gap
To measure end gap, insert piston ring (1) into cylinder bore and then measure the gap using thickness gauge (2).
If measured gap exceeds limit, replace ring.
NOTE:
Remove carbon and clean top of cylinder bore before inserting piston ring.
Piston ring end gap
