Figure 1. Diagnostic Form
The following procedure will lead you through the Valve Clearance Test. For a reproduction of the applicable portion of the diagnostic form, see Figure
The purpose of the valve clearance test is to determine if the valve clearance is correct.
Follow these steps to test the valve clearance:
- Remove the valve cover/intake manifold.
- Rotate the crankshaft until the No. 1 piston is on the compression stroke and the timing mark on the damper pulley is aligned with the TDC mark on the timing indicator.
Note: Confirm that the No. 1 piston is on the compression stroke by turning both pushrods by hand to verify both valves are closed. The valves are closed when the pushrods are loose and can be turned easily.
- Check the valve lash by inserting the feeler gage between the rocker arm and valve step tip. If adjustment is required, loosen the locknut and turn the valve adjustment screw until the valve lever can support the feeler gage. See Figure
“Valve Lash Check”
2. Feeler Gage Insertion
Figure 2. Valve Lash Check
- Tighten the locknut once the adjustment is set and remove the feeler gage. Continue checking and adjusting valves (if necessary) following the valve sequence shown. See Figure
“Valve Lash Adjustment Sequence”
Note: Six valves are adjusted when the No. 1 piston is at TDC (compression stroke) and the remaining six are adjusted when the No. 6 piston is at TDC (compression stroke).
Figure 3. Valve Lash Adjustment Sequence
Figure 4. Diagnostic Form
- For valve lash adjustments, see Figure
. Install the valve cover/intake manifold on the cylinder head. Tighten the mounting bolts to 13 lb·ft. (18 N·m). See Figure
“Torque Valve Cover / Intake Manifold”
Figure 5. Torque Valve Cover / Intake Manifold
Possible causes for valve lash problems are:
- Worn valve train
- Valve seat or face wear
|Series 40E Troubleshooting Manual – 6SE241|
|Generated on 10-13-2008|