Oil Pump: Service and Repair

Oil Pump Overhaul






Removal
1. Set the No. 1 piston at top dead center (TDC).
2. Remove the oil pan.





3. Remove and discard the oil pump chain tensioner.





4. To hold the rear balancer shaft, insert a 6 mm pin driver (A) into the maintenance hole in the lower balancer shaft holder and through the rear balancer shaft.
5. Loosen the oil pump sprocket mounting bolt.





6. Remove the oil pump sprocket (A), then remove the oil pump (B).

Inspection





1. Remove the pump housing.





2. Check the inner-to-outer rotor radial clearance between the inner rotor (A) and outer rotor (B). If the inner-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.
Inner Rotor-to-Outer Rotor Radial Clearance
Standard (New): 0.02 - 0.16 mm (0.001 - 0.006 inch)
Service Limit: 0.20 mm (0.008 inch)





3. Check the housing-to-rotor axial clearance between the rotor (A) and pump housing (B). If the housing to-rotor axial clearance exceeds the service limit, replace the oil pump.
Housing-to-Rotor Axial Clearance
Standard (New): 0.02 - 0.07 mm (0.001 - 0.003 inch)
Service Limit: 0.12 mm (0.005 inch)





4. Check the housing-to-outer rotor radial clearance between the outer rotor (A) and pump housing (BY If the housing-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.
Housing-to-Outer Rotor Radial Clearance
Standard (New): 0.15 - 0.21 mm (0.006 - 0.008 inch)
Service Limit: 0.23 mm (0.009 inch)
5. Inspect both rotors and the pump housing for scoring or other damage. Replace parts if necessary.

Balancer Shaft Inspection
1. Seat the balancer shaft by pushing it away from the oil pump sprocket end of the oil pump.





2. Zero the dial indicator against the end of the balancer shaft, then push the balancer shaft back and forth and read the end play.
Balancer Shaft End Play:
Front Balancer Shaft:
Standard (New): 0.070 - 0.135 mm (0.0028 - 0.0053 inch)
Service Limit: 0.15 mm (0.006 inch)
Rear Balancer Shaft:
Standard (New): 0.070 - 0.135 mm (0.0028 - 0.0053 inch)
Service Limit: 0.15 mm (0.006 inch)





3. Remove the baffle plate (A) and upper balancer shaft holder (with bearings) (B), then remove the front balancer shaft (C) and rear balancer shaft (D).








4. Measure the inner diameter of the No.1 bearing for the front balancer shaft hole and the rear balancer shaft hole.
Bearing Inner Diameter:
Front:
Standard (New): 20.000 - 20.020 mm (0.7874 - 0.7882 inch)
Service Limit: 20.03 mm (0.789 inch)
Rear:
Standard (New): 24.000 - 24.020 mm (0.9449 - 0.9457 inch)
Service Limit: 24.03 mm (0.946 inch)








5. Measure the diameters of the No.1 journals on the front balancer shaft and rear balancer shaft.
NO.1 Journal Diameter:
Front:
Standard (New): 19.938 - 19.950 mm (0.7850 - 0.7854 inch)
Service Limit: 19.92 mm (0.784 inch)
Rear:
Standard (New): 23.938 - 23.950 mm (0.9424 - 0.9429 inch)
Service Limit: 23.92 mm (0.942 inch)
6. Clean both balancer shaft No. 2 journals and bearing halves with a clean shop towel.
7. Place one strip of plastigage across each No. 2 journal.
8. Reinstall the bearings and upper balancer shaft holder, then torque the bolts.

NOTE: Do not rotate the balancer shaft during inspection.





9. Remove the upper balancer shaft holder and bearings again, and measure the widest part of the plastigage. If the balancer shaft No. 2 journal oil clearance is out-of-tolerance, install the new bearings, and recheck. If it is still out-of-tolerance, replace the balancer shafts.
No. 2 Journal Oil Clearance:
Standard (New): 0.060 - 0.120 mm (0.0024 - 0.0047 inch)
Service Limit: 0.15 mm (0.006 inch)





10. Align the punch mark on the rear balancer shaft with the center of the two punch marks on the front balancer shaft, then install the balancer shafts in the lower balancer shaft holder.





11. Apply engine oil to the threads of the 8 mm bolts (A).
12. Install the upper balancer shaft holder (B) and baffle plate (C).





13. Install the pump housing.

Installation
1. Make sure the No. 1 piston is at TDC.





2. Align the dowel pin (A) on the rear balancer shaft with the mark (B) on the oil pump.





3. To hold the rear balancer shaft, insert a 6 mm pin driver (A) into the maintenance hole in the lower balancer shaft holder and through the rear balancer shaft.





4. Apply engine oil to the threads of the oil pump sprocket mounting bolt (A).
5. Loosely install the oil pump (B), then install the oil pump sprocket (C).
6. Remove the pin driver (D).
7. Tighten the oil pump mounting bolts.





8. Squeeze the new oil pump chain tensioner (A), then install the set clip (B) on it as shown.

NOTE: The set clip is supplied with the oil pump chain tensioner.





9. Install the oil pump chain tensioner.





10. Remove the set clip from the oil pump chain tensioner.
11. Install the oil pan.