Heavy Duty Balanced Opposed Compressors

FOR MODELS: JG AND JGA SECTION 1 - DESIGN SPECIFICATIONS & DATA
TABLE 1-8: PISTON TO BORE CLEARANCE AND PISTON/RIDER RING END GAP, INCHES (mm) -
LUBRICATED M, P & SP CLASS CYLINDERS.
BORE
DIAMETERa PISTON TO BORE
PISTON/RIDER RING END GAP
CLEARANCE
NEW MAXIMUM
1.625 (41) 0.090 to 0.096 (2.29 to 2.44)
1.75 (44) 0.090 to 0.096 (2.29 to 2.44) 0.016 to 0.032 (0.41 to 0.81) 0.128 (3.25)
2.0625 (52) 0.090 to 0.096 (2.29 to 2.44) 0.020 to 0.036 (0.51 to 0.91) 0.144 (3.66)
2.25 (57) 0.090 to 0.096 (2.29 to 2.44) 0.023 to 0.039 (0.58 to 0.99) 0.156 (3.96)
2.5 (64) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
2.75 (70) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
3 (76) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
3.25 (83)) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
3.5 (89) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
3.75 (95) 0.090 to 0.096 (2.29 to 2.44) 0.044 to 0.060 (1.12 to 1.52 0.240 (6.10)
3.875 (98) 0.090 to 0.096 (2.29 to 2.44) 0.045 to 0.061 (1.14 to 1.55) 0.244 (6.20)
4.125 (105) 0.090 to 0.096 (2.29 to 2.44) 0.049 to 0.065 (1.24 to 1.65) 0.260 (6.60)
4.375 (111) 0.090 to 0.096 (2.29 to 2.44) 0.052 to 0.068 (1.32 to 1.73) 0.272 (6.91)
4.75 (121) 0.090 to 0.096 (2.29 to 2.44) 0.057 to 0.073 (1.45 to 1.85) 0.292 (7.42)
5.125 (130) 0.090 to 0.096 (2.29 to 2.44) 0.062 to 0.078 (1.57 to 1.98) 0.312 (7.93)
5.5 (140) 0.090 to 0.096 (2.29 to 2.44) 0.068 to 0.084 (1.73 to 2.13) 0.336 (8.53)
5.75 (146) 0.090 to 0.096 (2.29 to 2.44) 0.071 to 0.087 (1.80 to 2.21) 0.348 (8.84)
6.125 (156) 0.090 to 0.096 (2.29 to 2.44) 0.069 to 0.099 (1.75 to 2.51) 0.396 (10.06)
6.5 (165) 0.090 to 0.096 (2.29 to 2.44) 0.074 to 0.104 (1.88 to 2.64) 0.416 (10.57)
7.5 (191) 0.090 to 0.096 (2.29 to 2.44) b
b
8 (203) 0.090 to 0.096 (2.29 to 2.44) b b
a. Conventional piston rings are standard for all M, P and SP Class Cylinders, except for 1-3/4M-FS Class Cylinder with
bore diameters of 1.625” (41mm) and 1.75” (44) where piston/rider rings are standard. Piston/rider rings are optional for
all other lubricated M, P and SP Class Cylinders.
b. 8M x 3-1/2” (88.9 mm) stroke & 8SP-HE class cylinders, w/ 7.5” (191) bore: end gap, new is 0.099” to 0.129” (2.51 to
3.53), maximum is 0.516” (13.11).
8M x 3” (76.2) stroke, w/ 7.5” (191) bore: new 0.088” to 0.118” (2.24 to 3.00), maximum 0.472” (11.99).
8M x 3-1/2” (88.9) & 8SP-HE, w/ 8” (203) bore: new 0.106” to 0.136” (2.69 to 3.43), maximum 0.544” (14.07).
8M x 3” (76.2) w/ 8” (203) bore: new 0.095” to 0.125” (2.41 to 3.18), maximum 0.500” (12.70).
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