To adjust a lifter, specifically an intake lifter/rocker, you must accurately position the engine by observing the movement of the corresponding exhaust lifter.
How Do You Adjust an Intake Lifter/Rocker?
Adjusting an intake lifter, often done as part of valve lash setting, requires precise engine positioning to ensure the lifter is on the base circle of the camshaft lobe, allowing for accurate measurement and adjustment. The method described involves using the exhaust valve's position as a reference point for the intake valve of the same cylinder.
Step-by-Step Intake Lifter Adjustment
The procedure for adjusting an intake lifter/rocker, according to the provided method, focuses on observing the exhaust lifter's movement to achieve the correct engine position.
Here are the detailed steps:
- Rotate the Engine: Begin by slowly rotating the engine in its normal direction of rotation.
- Observe Exhaust Lifter: Carefully watch the exhaust lifter/rocker arm for the cylinder you intend to adjust.
- Low Portion of Cam: Continue rotating until the exhaust lifter is on the low portion of the cam, which indicates the exhaust valve is fully closed.
- Exhaust Lifter Starts to Rise: Keep rotating the engine slowly until the exhaust lifter just begins to rise. This point signifies that the exhaust valve is just starting to open.
- Stop Rotation: Immediately stop the engine rotation at this precise point.
- Adjust Intake Lifter: With the engine in this position, you are now ready to adjust the intake lifter/rocker for that specific cylinder. At this point, the intake lifter for the same cylinder will be on the base circle of its cam lobe, allowing for an accurate lash adjustment.
| Step | Action | Purpose |
|---|---|---|
| 1. Engine Rotation | Slowly rotate the engine. | To cycle through valve events and find the precise adjustment point. |
| 2. Observe Exhaust | Watch the exhaust lifter/rocker arm for the cylinder being worked on. | The exhaust lifter's movement indicates the cam lobe's position. |
| 3. Low Cam Portion | Rotate until the exhaust lifter is fully down. | Confirms the exhaust valve is closed, prior to its opening cycle. |
| 4. Exhaust Starts to Rise | Continue rotating until the exhaust lifter just begins to move upwards. | Signals the precise moment the exhaust valve is starting to open. |
| 5. Stop & Adjust | Stop the engine. The intake lifter/rocker for that cylinder is now in the correct position for adjustment. | Ensures the intake lifter is on the base circle of its cam for accurate lash. |
Understanding the "Exhaust Opening" Method
This specific method of adjusting the intake lifter by observing the exhaust valve's opening is a common technique, particularly for engines where the intake and exhaust valves share a common cam lobe profile or have a specific timing relationship. When the exhaust valve just begins to open, the corresponding intake valve for the same cylinder is typically on its base circle (fully closed and stable), which is the ideal position for setting valve lash or adjusting lifter preload. This ensures that the measurement is taken when there is no pressure from the cam lobe, providing the most accurate setting.
Key Considerations
- Precision is Crucial: Accurate engine positioning is paramount. Even slight over-rotation can lead to an inaccurate adjustment.
- Lifter Type: This adjustment method primarily applies to solid lifters where a specific lash (clearance) needs to be set. For hydraulic lifters, adjustment usually involves preloading to eliminate clearance rather than setting a specific gap. Always consult your vehicle's service manual for specific procedures and specifications.
- Proper Tools: Use appropriate feeler gauges (for solid lifters) or other specialized tools as required by the manufacturer's specifications for measurement and adjustment.
