Lincoln Workshop Service and Repair Manuals

Piston: Specifications

Diameter [1] 

Without Coating

Red 1 ...................................................................................................................................................  90.167-90.180 mm (3.549875-3.550387 inch)
Blue 2 ..................................................................................................................................................  90.180-90.193 mm (3.550387-3.550898 inch)
Yellow 3 ..............................................................................................................................................  90.193-90.206 mm (3.550898-3.551417 inch)

With Coating

Red 1 ...................................................................................................................................................  90.187-90.238 mm (3.550669-3.552677 inch)
Blue 2 ..................................................................................................................................................  90.200-90.225 mm (3.551181-3.552165 inch)
Yellow 3 ..............................................................................................................................................  90.213-90.238 mm (3.551693-3.552677 inch)

Piston-to-Bore [2] 

Clearance Limit .............................................................................................................................................  0.012-0.026 mm (0.000472-0.001024 inch)

Piston Pin Bore ..........................................................................................................................................  22.0015-22.004 mm (0.866199-0.866297 inch)
Ring Groove Width: 

Compression, Top .........................................................................................................................................  1.530-1.550 mm (0.060236-0.061024 inch)
Compression, Bottom ....................................................................................................................................  1.520-1.530 mm (0.059842-0.060236 inch)
Oil .................................................................................................................................................................  6.996-7.224 mm (0.275433-0.284409 inch)

[1] Measured 42 mm (1.654 inch) from dome of piston, 90° to the pin. Piston diameter excludes 0.02-0.03 mm (0.000787-0.001181 inch) of coating.
[2] Piston-to-bore fit measurements must be done by measuring bore and matching corresponding bore color with the same piston color.