Oil Pump: Service and Repair

Engine Oil Pump Overhaul

Exploded View





Oil Pump Removal

1. Set the No 1 piston at top dead center (TDC).. Cam Chain Removal

2. Remove the oil pan. Engine Oil Pan Removal

3. Remove and discard the oil pump chain tensioner.






4. To hold the rear balancer shaft, insert a 6 mm pin punch (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).






Oil Pump 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.










3. Check the pump housing-to-rotor axial clearance between the rotor (A) and pump housing (B). If the pump housing-to-rotor axial clearance exceeds the service limit, replace the oil pump.










4. Check the pump housing-to-outer rotor radial clearance between the outer rotor (A) and the pump housing (B). If the pump housing-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.





5. Inspect both rotors and the pump housing for scoring or other damage. Replace the 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.














3. Remove the pump housing.






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






5. Measure the inner diameter of the No. 1 bearing for the front balancer shaft hole and the rear balancer shaft hole.





Front





Rear





6. Measure the diameters of the No. 1 journals on the front balancer shaft and rear balancer shaft.





7. Clean both balancer shaft No. 2 journals and the bearing halves with a clean shop towel.

8. Place one strip of plastigage across each No. 2 journal.

Front





Rear





9. Reinstall the bearings and upper balancer shaft holder, then tighten the bolts.
NOTE: Do not rotate the balancer shafts during inspection.






10. Remove the upper balancer shaft holder and the bearings again, and measure the widest part of the plastigage. If the balancer shaft No. 2 journal oil clearance is out-of-tolerance, install new bearings, and recheck. If it is still out-of-tolerance, replace the balancer shafts.










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






12. Apply new engine oil to the threads of the 8 mm bolts (A).

13. Install the upper balancer shaft holder (B) and baffle plate (C).






14. Install the pump housing.






Oil Pump Installation

1. Make sure the No 1 piston is at TDC.. Cam Chain Removal

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 punch (A) into the maintenance hole in the lower balancer shaft holder and through the rear balancer shaft.






4. Apply new 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 punch (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 new oil pump chain tensioner.






10. Remove the set clip from the oil pump chain tensioner.

11. Install the oil pan. Engine Oil Pan Installation