- Machine Engines
During an engine overhaul, inspect the oil pump idler gear shaft. The gear shaft must be serviced if you can push in the gear shaft and the gear shaft can be turned in the bearing cap by hand. The bearing cap must be bored and an oversized idler shaft must be used. The new oversized idler shaft is 231-3497 Idler Shaft.
Note: The oversized idler shaft has an "S" that is stamped on the end of the large diameter of the shaft.
Use the following steps to remove the oil pump idler gear shaft:
- Remove the bearing cap from the engine.
- Remove the idler shaft from the bearing cap.
Use the following steps to install the new oil pump idler gear shaft:
- Ensure that the bore in the bearing cap for the idler shaft is clean.
- Ensure that the bearing cap is correctly supported on the front face that is machined.
Illustration 1 g02740896 Dimensions for the main bearing cap on four cylinder engines Illustration 2 g02740897 Dimensions for the main bearing cap on six cylinder engines Illustration 3 g01009904 View A-A
- Ensure that the correct datum is used. Refer to Illustration 1, Illustration 2, and Illustration 3 for the locations of the following dimensions.
(A) The location for center of bore from top of bearing cap on four cylinder engines ...
61.900 to 61.966 mm (2.4370 to 2.4396 inch)
(A) The location for center of bore from top of bearing cap for six cylinder engines ...
72.679 to 72.749 mm (2.8614 to 2.8641 inch)
(B) Location for center of bore from center line of bearing cap on four cylinder engines ...
16.637 to 16.688 mm (0.6550 to 0.6570 inch)
(B) Location for center of bore from center line of bearing cap on six cylinder engines ...
9.225 to 9.275 mm (0.363 to 0.365 inch)
(C) Diameter of original bore ...
16.695 to 16.570 mm (0.65728 to 0.65236 inch)
(D) Angle of chamfer ... 15 degrees
(E) Depth of chamfer ...
1.5 mm (0.06 inch)
- Bore the hole in the bearing cap for the idler shaft to a value of
18.000 to 18.025 mm (0.70866 to 0.70964 inch).
Note: The surface finish must be 1.6 µm. The perpendicularity of the bore must be
0.025 mm (0.0010 inch).
- Chamfer the bore for the idler shaft. Use Dimension (D) and Dimension (E). Remove all sharp edges.
- Apply 4C-9506 Retaining Compound to the small diameter of the 231-3497 Idler Shaft.
Illustration 4 g01009905
- The idler shaft (3) has oil hole (2). Ensure that oil hole (2) is toward the oil pump and that flat (1) is toward the crankshaft. This alignment must occur before the idler shaft is pressed into the bearing cap.
- Position the chamfer of the idler shaft into the hole in the bearing cap. Ensure that the idler shaft is square to the bearing cap.
- Press the idler shaft into the bearing cap. Remove any excess 4C-9506 Retaining Compound. Ensure that the oil hole is free from the retaining compound.