21538022 Volvo.Penta Air filter

The piston pin plug prevents the piston pin from scuffing the cylinder wall. The piston pin plug does not retain the pin into the assembly. Once the piston assembly is removed from the cylinder liner, the piston pin is free to fall out of the piston assembly at any time.
(1) The piston is a symmetrical with a center crater.Lubricate the entire piston in zone (A) prior to assembly into the cylinder block. Use clean engine oil.(2) Top piston ring Install the piston ring with the side marked "UP-1" toward the top of the piston. The red stripe faces to the right of the piston ring end gap.The ends of the piston ring have a clearance when the piston ring is installed in a cylinder line with a bore of 125.000 mm (4.9213 inch). Clearance ... 0.625 0.185 mm (.0250 .0073 inch)The piston ring has an increase in clearance for each 0.03 mm (.001 inch) increase in the cylinder liner bore. Increase ... 0.09 mm (.004 inch)Minimum depth of the groove in new piston for the top ring ... 5.43 mm (.214 inch)(3) Intermediate piston ring Install the piston ring with the side marked "UP-2" toward the top of the piston. The blue stripe faces to the right of the piston ring end gap.Width of groove in new piston for intermediate piston ring ... 3.061 0.013 mm (.1205 .0005 inch)Minimum depth of groove in new piston for intermediate piston ring ... 5.43 mm (.214 inch)Thickness of new intermediate piston ring ... 2.988 0.013 mm (.1176 .0005 inch) Clearance between groove and intermediate piston ring ... 0.047 to 0.099 mm (.0019 to .0039 inch)The ends of the piston ring have a clearance when the piston ring is installed in a cylinder liner with a bore of 125.000 mm (4.9213 inch). Clearance ... 0.625 0.125 mm (.0246 .0049 inch)The intermediate piston ring has an increase in clearance for each 0.03 mm (.001 inch) increase in the cylinder liner bore. Increase ... 0.09 mm (.004 inch)(4) Oil control piston ring The ends of the oil control piston ring should be a distance of 180 degrees from the ring end gap when the oil control piston ring is assembled. The orange colored portion of the piston ring must be visible at the ring end gap.Width of groove in new piston for oil control piston ring ... 4.033 0.013 mm (.1588 .0005 inch)Minimum depth of groove in new piston for oil control piston ring ... 3.727 mm (.1467 inch)Thickness of new oil control piston ring ... 3.987 0.013 mm (.1570 .0005 inch) Clearance between groove and oil control piston ring ... 0.020 to 0.072 mm (.0008 to .0028 inch)The ends of the piston ring have a clearance when the piston ring is installed in a cylinder liner with a bore of 125.000 mm (4.9213 inch). Clearance ... 0.44 0.15 mm (.017 .006 inch)The piston ring has an increase in clearance for each 0.03 mm (.001 inch) increase in the cylinder liner bore. Increase ... 0.09 mm (.004 inch)After the piston rings have been installed, rotate the piston rings so that the end gaps are 120 degrees from each other.(5) Crown assembly(6) Piston pin bore diameter that is in the piston skirt ... 50.815 0.005 mm (2.0006 .0002 inch)Piston pin bore diameter that is in the bearing of the crown assembly ... 50.830 0.008 mm (2.0012 .0003 inch)Thoroughly lubricate the piston pin with clean engine oil prior to assembly.(7) Piston skirt