PUMP GP-PISTON 2400149 - Caterpillar

Illustration 1 g02803856
(1) Top Ring
(2) Intermediate Ring
(3) Oil Control Ring
(4) Piston Pin Snap Ring
(5) Piston
(6) Connecting Rod
(7) Piston Pin
Illustration 2 g03381826
Ring gap measurement
Illustration 3 g03381858
Ring groove measurement
Table 1
Specifications for Top Piston Ring
Top ring gap (New) 0.20 mm (0.00787 inch) to 0.35 mm (0.01378 inch)
Allowable Limit 1.20 mm (0.04724 inch)
Table 2
Specifications for Intermediate Piston Ring
Intermediate ring gap (New) 0.30 mm (0.012 inch) to 0.45 mm (0.018 inch)
Allowable Limit 1.25 mm (0.049 inch)
Clearance from the intermediate ring to the ring groove (New) 0.0850 mm (0.00335 inch) to 0.112 mm (0.00441 inch)
Allowable Limit 0.20 mm (0.008 inch)
Table 3
Specifications for Oil Control Ring
Oil control ring gap (New) 0.30 mm (0.01181 inch) to 0.55 mm (0.02165 inch)
Allowable Limit 1.25 mm (0.049 inch)
Clearance between oil control ring to ring groove (New) 0.020 mm (0.00079 inch) to 0.060 mm (0.00236 inch)
Allowable Limit 0.15 mm (0.0059 inch) Piston Pin Bore Inside Diameter
Illustration 4 g02811198
(8) Cylinder gauge
Measure the piston pin bore I.D. in the horizontal and vertical directions with a cylinder gauge.
Table 4
Inside diameter of piston pin bore (New) 22.000 mm (0.86614 inch) to 20.013 mm (0.78791 inch)
Allowable Limit 22.03 mm (0.86732 inch)
Measure the small end bushing inside diameter with an internal micrometer.
Table 5
Inside diameter of small end bushing (New) 22.025 mm (0.86712 inch) to 22.040 mm (0.86771 inch)
Piston pin outside diameter (New) 22.002 mm (0.86622 inch) to 22.011 mm (0.86657 inch)
Calculate the oil clearance.
Table 6
Oil clearance between piston pin outside diameter and small end bushing (New) 0.014 mm (0.00055 inch) to 0.038 mm (0.00150 inch)
Allowable limit 0.15 mm (0.0059 inch)
If the oil clearance is more than the allowable limit, replace the bushing.
If the oil clearance stays more than the allowable limit, replace the piston pin also.