Standard Procedure - Injector Clearance
NOTE:
The injector clearance adjustment procedure must be performed any time an injector has been removed from the cylinder head.
NOTE:
The injector clearance adjustment procedure sets the minimum clearance between the tip of the injector pump piston and the bottom of the injector bore. The injector clearance adjustment procedure prevents the injector pump piston from contacting the bottom of the injector bore due to normal heat expansion of injector parts that will occur during engine operation.
- Using a suitable tool, rotate the crankshaft in the direction of engine rotation until the roller of the rocker arm (8) is positioned on the base of the drive cam.
- Mount a dial indicator gauge on the cylinder head cover mounting surface.
- Position the measurement tip (1) of the dial indicator gauge on the top edge of the adjustment screw (2) of the unit injector (3).
- Zero the dial indicator.
- Using a suitable tool, rotate the crankshaft in the direction of engine rotation until the roller of the rocker arm for the injector being adjusted is positioned on the peak of the drive cam.
- While observing the readings on the dial indicator, slowly rotate the crankshaft approximately 2° in the opposite direction of engine rotation and in the direction of engine rotation to determine the extreme bottom point of injector pump piston (1) travel inside the injector bore. The extreme bottom point of injector travel will be the point of crankshaft rotation where the readings on the dial indicator stop rising, but before the readings begin to decrease.
- Remove the dial indicator.
- If necessary, loosen the adjustment screw locknut (5). Using an Allen wrench, tighten the adjustment screw (4) into rocker arm until a firm resistance is felt. At this point, the injector pump piston is bottomed out at the base of the injector bore.
- Loosen the adjustment screw 225° to allow the injector pump piston to back off the base of the injector bore.
- Hold adjustment screw in this position and tighten the adjustment screw lock nut to 30 Nm/22 lb-ft.