Engine Oil Pump Overhaul

Exploded View
Oil Pump Removal
  1. Set the crankshaft to top dead center (TDC). Align the key (A) on the crankshaft with the pointer (B) on the chain case.
  1. Loosely install the crankshaft pulley.
  1. To hold the rear balancer shaft, insert a 8 mm long pin punch (A) (Snap-on PPC110LA or equivalent) into the maintenance hole in the balancer shaft holder and through the rear balancer shaft.
  1. Turn the crankshaft counterclockwise to compress the oil pump chain auto-tensioner.
  1. Align the holes on the lock (A) and the oil pump chain auto-tensioner (B), then insert a 2.5 mm (0.1 in.) diameter pin or stopper (P/N 13451-RBD-003) (C) into the holes. Turn the crankshaft clockwise to secure the pin.
  1. Remove the oil pump chain auto-tensioner.
  1. Loosen the oil pump sprocket mounting bolt.
  1. Remove the oil pump sprocket (A) and key (B), then remove the oil pump (C).
Oil Pump Inspection
  1. Remove the pump housing.
  1. 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):
    0.02−0.14 mm
    (0.0008−0.0055 in.)
    Service Limit:
    0.19 mm (0.0075 in.)

  1. Check the housing-to-rotor axial clearance between the rotor (A) and lower balancer shaft holder (B). If the housing-to-rotor axial clearance exceeds the service limit, replace the oil pump.
    Housing-to-Rotor Axial Clearance
    Standard (New):
    0.020−0.055 mm
    (0.0008−0.0022 in.)
    Service Limit:
    0.1 mm (0.004 in.)

  1. Check the housing-to-outer rotor radial clearance between the outer rotor (A) and lower balancer shaft holder (B). 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 in.)
    Service Limit:
    0.23 mm (0.009 in.)

Balancer Shaft Inspection
  1. Seat the balancer shaft by pushing it away from the oil pump sprocket end of the oil pump.
  1. 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
    Standard (New):
    0.070−0.140 mm
    (0.0028−0.0055 in.)
    Service Limit:
    0.15 mm (0.006 in.)

  1. Remove the pump housing.
  1. Remove the upper balancer shaft holder (with bearings) (A), then remove the front balancer shaft (B) and rear balancer shaft (C).
  1. Measure the inner diameter of the No. 1 bearing for the rear balancer shaft hole.
    Bearing Inner Diameter
    Standard (New):
    24.000−24.020 mm
    (0.9449−0.9457 in.)
    Service Limit:
    24.03 mm (0.946 in.)

  1. Measure the diameter of the No. 1 journal on the rear balancer shaft.
    Journal Diameter
    Standard (New):
    23.938−23.950 mm
    (0.9424−0.9429 in.)
    Service Limit:
    23.92 mm (0.942 in.)

  1. Clean both balancer shaft No. 2 journals and balancer shaft holders with a clean shop towel.
  1. Place one strip of plastigage across each No. 2 journals.
  1. Reinstall the bearings and upper balancer shaft holder, then torque the bolts.
    NOTE: Do not rotate the balancer shafts during inspection.
  1. 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, replace the balancer shafts and recheck. If it still out-of-tolerance; replace the oil pump.
    No. 2 Journal Oil Clearance
    Standard (New):
    0.050−0.082 mm
    (0.0020−0.0032 in.)
    Service Limit:
    0.11 mm (0.004 in.)

  1. Clean both balancer shaft No. 3 journals and bearings with a clean shop towel.
  1. Place one strip of plastigage across each No. 3 journals.
  1. Reinstall the bearings and upper balancer shaft holder, then torque the bolts.
    NOTE: Do not rotate the balancer shafts during inspection.
  1. Remove the upper balancer shaft holder and bearings again, and measure the widest part of the plastigage.
    If the balancer shaft No. 3 journal oil clearance is out-of-tolerance, install new bearings, and recheck. If it still out-of-tolerance; replace the balancer shafts.
    No. 3 Journal Oil Clearance
    Standard (New):
    0.060−0.120 mm
    (0.0024−0.0047 in.)
    Service Limit:
    0.15 mm (0.006 in.)

  1. 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.
  1. Apply new engine oil to the threads of the 8 mm bolts (A).
  1. Install the oil control orifice (B) with new O-ring (C), then install the upper balancer shaft holder (D).
  1. Install the outer rotor (A) and inner rotor (B) in the balancer shaft holder, then install the oil pump housing (C).
Oil Pump Installation
  1. Remove the crankshaft, and check the key (A) on the crankshaft and the pointer (B) on the chain case are aligned.
  1. Align the groove (A) on the rear balancer shaft with the mark (B) on the oil pump.
  1. To hold the rear balancer shaft, insert a 8 mm long pin punch (A) (Snap-on PPC110LA or equivalent) into the maintenance hole in the balancer shaft holder and through the rear balancer shaft.
  1. Apply new engine oil to the threads of the oil pump sprocket mounting bolt (A).
  1. Loosely install the oil pump (B), then install the key (C) and the oil pump sprocket (D), and tighten the mounting bolt.
  1. Remove the pin punch (E).
  1. Tighten the oil pump mounting bolt.
  1. Install the oil pump chain auto-tensioner.
  1. Remove the pin from the oil pump chain auto-tensioner.