Mark Howell from AVI demonstrates a valve lash adjustment on a PACCAR MX-13 2017 EPA engine. The required specs are on the engine tag.
Procedure:
- Remove the valve cover and disconnect the injector harness.
- Remove the injector harness and undo the injector connections beneath the valve cover.
- The engine firing order is 1-5-3-6-2-4.
- Use a special barring tool to rotate the engine at the side, removing the cover first.
- Bar the engine over to align the flywheel to the ‘1 and 6’ mark with the peg.
- Gather tools: 0.020″ intake feeler gauge, 0.028″ exhaust feeler gauge (special type), 5mm Allen head, and 18mm wrench.
- Adjustment: At the ‘1 and 6’ position, if cylinder 1’s valves are loose (not overlapped/tight), adjust them.
- Intake: Loosen the jam nut. Place the 0.020″ feeler gauge between the pad and the top of the bridge. Adjust the screw until snug with a slight drag. Hold the screw while tightening the jam nut. Check the clearance frequently, as tightening the jam nut increases the tension. The jam nut torque is 64 Newton meters (check your specific engine specs). Readjust if it becomes too tight after torquing.
- Exhaust (with engine brake): The exhaust is the longer rocker arm. Loosen the jam nut. Use the two-sided 0.028″ feeler gauge and align it with the copper pad. Adjust until snug.
- Bar the engine over to the next pair (e.g., ‘2 and 5’). Repeat the adjustment procedure following the 1-5-3-6-2-4 firing order.
- After adjusting, mark the component with a paint stick.
- The intake feeler gauge is placed under the pan on top of the bridge; the exhaust feeler gauge goes underneath the rocker arm and the top pad, aligning with the brass-looking part.
- Continue barring and adjusting until all cylinders (1, 5, 3, 6, 2, 4) are completed.
Contact AVI for any questions.
