5-34 ENGINE TOP END
Piston Ring, Piston Ring Groove Wear Inspection
Check for uneven groove wear by inspecting the ring seat-
The rings should fit perfectly parallel to groove surfaces.
If not, replace the piston and all the piston rings.
With the piston rings in their grooves, make several mea-
surements with a thickness gauge [A] to determine piston
Piston Ring/Groove Clearance
0.05 ∼ 0.09 mm (0.0020 ∼ 0.0035 in.)
0.03 ∼ 0.07 mm (0.0012 ∼ 0.0028 in.)
0.19 mm (0.0075 in.)
0.17 mm (0.0067 in.)
Piston Ring Groove Width Inspection
Measure the piston ring groove width.
Use a vernier caliper at several points around the piston.
Piston Ring Groove Width
0.84 ∼ 0.86 mm (0.0330 ∼ 0.0339 in.)
Second [B] 0.82 ∼ 0.84 mm (0.0323 ∼ 0.0331 in.)
0.94 mm (0.037 in.)
Second [B] 0.92 mm (0.036 in.)
If the width of any of the two grooves is wider than the
service limit at any point, replace the piston.
Piston Ring Thickness Inspection
Measure the piston ring thickness.
Use the micrometer to measure at several points around
Piston Ring Thickness
0.77 ∼ 0.79 mm (0.0303 ∼ 0.0311 in.)
Second [B] 0.77 ∼ 0.79 mm (0.0303 ∼ 0.0311 in.)
0.70 mm (0.028 in.)
Second [B] 0.70 mm (0.028 in.)
If any of the measurements is less than the service limit
on either of the rings, replace all the rings.
When using new rings in a used piston, check for un-
even groove wear. The rings should fit perfectly parallel
to the groove sides. If not, replace the piston.