C3.3B Tier 4 Final Engines for Caterpillar Built Machines Caterpillar

Illustration 1	g03361184
View of oil pump

Clearance between Inner Rotor and Outer Rotor

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Illustration 2	g02914136

1. Measure the clearance between the lobes of the inner rotor and the outer rotor with a feeler gauge.
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   Table 3

   Clearance between Inner Rotor and Outer Rotor	Factory specification	0.030 mm (0.0012 inch) to 0.090 mm (0.0035 inch)
   	Allowable limit	0.3 mm (0.01 inch)

2. If the clearance exceeds the allowable limit, replace the oil pump rotor assembly.

Clearance Between Outer Rotor and Pump Body

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Illustration 3	g02914137

1. Measure the clearance between the outer rotor and the pump body with a feeler gauge.
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   Table 4

   Clearance between outer rotor and pump body	Factory specification	0.100 mm (0.00394 inch) to 0.184 mm (0.00724 inch)
   	Allowable limit	0.3 mm (0.01 inch)

2. If the clearance exceeds the allowable limit, replace the oil pump rotor assembly.

3. If still the clearance exceeds the allowable limit after replacing the oil pump rotor assembly, replace the gear case.

Clearance Between Rotor and Cover

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Illustration 4	g02914138

1. Put a strip of Plastigage on the rotor face with grease.

2. Install the cover and tighten the screws with the specified torque.

3. Remove the cover carefully.

4. Measure the width that Plastigage becomes flat with the scale to get the oil clearance.
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   Table 5

   Clearance between rotor and cover	Factory specification	0.025 to 0.075 mm (0.00099 to 0.0029 inch)
   	Allowable limit	0.225 mm (0.00886 inch)

5. If the clearance is more than the allowable limit, replace oil pump rotor assembly and the cover.