All Engines Except 4XE1 (1.6L DOHC) and V6
The valves are adjusted with the engine COLD. It is best to allow an engine to sit overnight before beginning a valve adjustment. While all valve adjustments must be made as accurately as possible, it is better to have the adjustment slightly loose rather than slightly tight. A burned valve may result from overly tight valve adjustments.
- Remove the rocker arm cover and discard the gasket.
- Make sure both the cylinder head and camshaft retaining bolts are tightened to the proper torque.
- Rotate the crankshaft pulley until the No. 1 piston is at TDC of the compression stroke.
To make sure the piston is on the correct stroke, remove the spark plug and place a finger over the hole. Feel for air being forced out of the spark plug hole. Both valves on No. 1 cylinder will be closed. Stop turning the crankshaft when the TDC timing mark on the crankshaft pulley is directly aligned with the timing mark pointer.
- With the No. 1 piston at TDC of the compression stroke, adjust the clearance according to the "Valve Adjusting Sequence" illustrations in this section.
- Adjust the clearance by loosening the locknut and turning the adjusting screw. Retightening the locknut when the proper thickness feeler gauge passes between the camshaft or valve stem and has a slight drag when the clearance is corrected.
- Rotate the crankshaft 1 complete revolution (360and#x00B0;) to position the No. 4 piston at TDC of its compression stroke and adjust the clearances as shown in the illustration.
- After adjustment, use a new gasket, sealant and install the rocker arm cover.
Inspect and adjust the valve clearance when the engine is COLD. Retorque the camshaft bearing cap bolts to 7 ft. lbs. (10 Nm) before inspecting and adjusting valve clearance.
- Remove the cylinder head cover.
- Remove the spark plugs.
- Set the No. 1 cylinder to TDC on the compression stroke by turning the crankshaft pulley and align the notched line with the 0 mark on the timing cover. Check that the tappets on the No. 1 have play and tappets on the No. 4 have no play. If not, turn the crankshaft one revolution and align the marks as above.
- The allowable valve clearance is 0.004 and 190.008 in. (0.10 and 190.20mm) for intake and 0.008 and 190.012 in. (0.20 and 190.30mm).
- Measure the clearance between the cam lobe and adjuster (shim) of the valves. Refer to "Valve Adjuster Sequence" illustration in the section.
- Record the measurements which are out of the allowable clearance.
- Turn the crankshaft one revolution and measure the remaining valves, refer to the "Valve Adjuster Sequence" illustration.
- The valves are adjusted by replacing the shims.
- Press down the tappet by the cam lift, turning the camshaft. Place the spacer tool J-38413-2 on the upper circumference of the tappet from the outside of the cylinder head.
- Release the cam lift by turning the camshaft and hold the tappet down with the spacer tool. Remove the shim from the spark plug side with a small prybar or magnetic finger. Use the cutaway in the tappet to remove the shim.
- Determine the thickness of the shim by using the following formula and accompanying charts:
- Measure the thickness of the original shim with a micrometer.
- Calculate the thickness of an available shim so that the valve clearance comes within the allowable value.
- Ta = thickness of the available shim
- M = measured valve clearance
- To = thickness of original shim
- M + To = Ta
- Select the available shim with a thickness as close as possible to the calculated values.
- Install the shim by placing it into the tappet. Press down the tappet by turning the camshaft and remove the spacer tool.
- Install the cylinder head cover.
- Remove the rocker arm cover.
- Rotate the crankshaft until the No. 1 cylinder is on TDC of its compression stroke.
When the notch on the damper pulley is aligned with the 0 timing mark and the rocker arms of the No. 1 cylinder do not move, the engine is at TDC of the compression stroke of the No. 1 cylinder.
- With the engine at TDC of the No. 1 cylinder, adjust the following valves:
- Exhaust: 1, 2 and 3
- Intake: 1, 5 and 6
- Back out the adjusting nut until lash is felt.
- Tighten the adjusting nut until the lash is removed, then, turn the nut 1 1 / 2 additional turns to center the lifter plunger.
- Rotate the engine 1 complete revolution and reposition the notch on the damper pulley with the 0 make on the timing tab. this is the No. 4 firing position.
- With the engine at TDC of the No. 4 cylinder, adjust the following valves:
- Exhaust: 4, 5 and 6
- Intake: 2, 3 and 4
- Back out the adjusting nut until lash is felt.
- Tighten the adjusting nut until the lash is removed, plus, turn the nut 1 1 / 2 additional turns to center to lifter plunger.
- Using a new gasket and sealant, install the rocker arm cover.