Valve Clearance: Adjustments
Valve Lash Adjustment^ Tools Required
- J 26900-13 Magnetic Indicator Base
- J 8001 Dial Indicator Set
- J 45785-1 Valve Spring Compressor
Important:
^ Valve clearance measurement should only be done on a cold engine.
^ To change the valve clearance on a given valve, the valve shim must be replaced by one that is thicker or thinner in size.
^ Valve shims are available in 41 different sizes, in increments of 0.020 mm (0.0008 inch).
^ Valve shims range in size from 2.000 mm (0.0787 inch) to 2.800 mm (0.1102 inch).
1. Remove the cylinder head cover.
2. Turn the crankshaft clockwise until the alignment notch on the crankshaft pulley is aligned with the "0" mark on the engine front cover tab.
3. Check that the point marks on the camshaft gears are aligned. If the point marks on the camshaft gears are not aligned, turn the crankshaft clockwise one revolution in order to align the camshaft gears.
4. Using a feeler gage, measure the clearance between the intake valve shims and the intake camshaft for cylinders #1, and #2.
Intake Valve Clearance (Cold): 0.08 - 0.18 mm (0.0031 - 0.0071 inch)
Important: Record any out of specification valve clearance measurements. The measurements will be used later to determine the required replacement shim.
5. Using a feeler gage, measure the clearance between the exhaust valve shims and the exhaust camshaft for cylinders #1, and #3.
Exhaust Valve Clearance (Cold): 0.22 - 0.32 mm (0.0087 - 0.0126 inch)
Important: Record any out of specification valve clearance measurements. The measurements will be used later to determine the required replacement shim.
6. Turn the crankshaft clockwise 1 revolution until the alignment notch on the crankshaft pulley is aligned with the "0" mark on the engine front cover tab.
7. Using a feeler gage, measure the clearance between the intake valve shims and the intake camshaft for cylinders #3, and #4.
Intake Valve Clearance (Cold): 0.08 - 0.18 mm (0.0031 - 0.0071 inch)
Important: Record any out of specification valve clearance measurements. The measurements will be used later to determine the required replacement shim.
8. Using a feeler gage, measure the clearance between the exhaust valve shims and the exhaust camshaft for cylinders #2, and #4.
Exhaust Valve Clearance (Cold): 0.22 - 0.32 mm (0.0087 - 0.0126 inch)
Important: Record any out of specification valve clearance measurements. The measurements will be used later to determine the required replacement shim.
9. If there were any valve clearances that were out of specifications, the valve shims must be replaced.
Valve Clearance Adjustment
1. Turn the crankshaft so the related rocker arm, where the valve clearance is to be adjusted, is fully pushed down.
2. Install J 45785-1 onto the spark plug tube.
Important: To avoid unlocking the valve spring keeper, do not allow clearance between the valve retainer and J 45785-1.
3. Operate the lever on J 45785 so the tool seat surface comes to contact with the valve retainer and lock them with the set screw.
4. Lock the set screw on the spark plug tube side of J 45785.
5. Rotate the crankshaft so the camshaft is positioned as shown.
6. Using J 45785, remove the valve adjusting shim as follows:
7. Lift the rocker arm and remove the valve adjusting shim.
Valve Shim Selection
Important: In order to maintain the specified valve clearance the proper shim must be selected. Perform the following procedure in order to select the proper shim:
1. Determine the valve(s) clearances that were out of specifications.
2. Remove the shim(s) from the out of specification valves.
3. Use a J 26900-13 and J 8001 to measure the thickness of the removed shim.
4. After measuring the shim, determine the size of the replaced shim according to the formula as follows:
^ A = Thickness of used shim
^ B = Measured valve clearance
^ C = Thickness of new shim
Intake Valve: C = A + (B - 0.13 mm (0.0051 inch)) x 1.5
Exhaust Valve: C = A + (B - 0.27 mm (0.0106 inch)) x 1.5
Shims are available in 41 size increments of 0.020 mm (0.0008 inch), from 2.000 mm (0.0787 inch) to 2.800 mm (0.1102 inch).
5. After selecting the proper shim, re-measure the valve clearance.
6. Install the cylinder head cover.