Valve Clearance: Adjustments
THIS ARTICLE HAS BEEN UPDATEDNOTE:
- Valve adjustment can be done either on-vehicle or off-vehicle.
- To measure exhaust valves, you need a 0.25 mm and a 0.35 mm feeler gauge.
- To measure intake valves, you need a 0.23 mm and a 0.33 mm feeler gauge. Since these are odd sizes, you may need to stack two gauges (for example, 0.11 mm and 0.12 mm to make 0.23 mm). If you do this, make sure the gauges are clean and in good condition. If you're not sure the gauge stack is correct, measure it with a micrometer.
On-Vehicle Valve Adjustment
1. Make a copy of the Valve Inspection Chart.
2. Make a copy of the Valve Shim Replacement Chart, then tape the pages together, side-by-side.
3. Remove the cylinder head covers.
4. Measure the valve clearances using the Go/No-Go method (see the note below). The clearances must be
- Intake valves: 0.25 mm +/- 0.05 mm
- Exhaust valves: 0.30 mm +/- 0.05 mm
NOTE:
- To measure with the Go/No-Go method, use two feeler gauges, one to measure the smallest allowable clearance, and the other to measure the largest.
- If the small gauge fits and the large gauge doesn't, the valve adjustment is OK.
- If the small gauge doesn't fit, or if the large gauge slides easily, the valve needs adjustment.
- The feeler gauges slide through the clearance gap at a slight angle, making the drag a little more than it would be on other engines.
5. For valves with the correct clearance, draw an "X" in the appropriate circle on the Valve Inspection Chart. For valves with incorrect clearances, write down the clearance you measured in the circle.
6. If you need to replace a valve shim, turn the crankshaft (or camshaft) until the cam lobe for the valve points away from the valve.
7. Turn the valve tappet with a pick or a small screwdriver until the tappet notch is within the indentation in the head.
8. Turn the crankshaft (or camshaft) pulley clockwise until the cam lobe presses the valve fully open.
9. On the tappet side closest to the bearing cap, insert the valve adjuster holder (T/N J-42659-AH) between the camshaft and the tappet. The tool should rest on the edge of the tappet without touching the shim.
10. Slowly turn the crankshaft (or camshaft) pulley counterclockwise so that when the valve closes, the tool catches between the camshaft and the tappet, holding the valve slightly open.
NOTE:
Do not turn the crankshaft (or camshaft) pulley too far or in the wrong direction. If you do, you might break the tool, or worse yet, damage the cylinder head.
11. Insert a pick or a small screwdriver into the tappet notch, and pry out the shim.
12. Wipe off the shim, then write its number on the Valve Inspection Chart for that valve and cylinder. If there is no number on the shim, measure its thickness with a micrometer, and write down the measurement on the Valve Inspection Chart.
13. Follow the directions on the Valve Shim Replacement Chart to select the correct shim.
14. Insert the correct shim, number side down, into the tappet. Make sure the shim is fully seated.
15. Release and remove the tool by turning the crankshaft (or camshaft) pulley clockwise.
16. Turn the crankshaft (or camshaft) pulley clockwise until the cam lobe again points away from the valve.
17. Recheck the valve clearance using the Go/No-Go method (see step 4).
- If the clearance is OK, repeat steps 6 thru 17 for the other valves needing adjustment.
- If the clearance is still incorrect, repeat steps 6 through 17 until it is correct, then adjust the remaining valves.
18. Turn the camshaft pulleys until the single timing dot (right cylinder bank) and dual timing dots (left cylinder bank) align with the single timing dots on the camshaft drive gears.
19. Install the cylinder head covers with new gaskets. Torque the cover bolts to 9 N.m (6.5 lb-ft).
Off-Vehicle Valve Adjustment
1. Make a copy of the Valve Inspection Chart.
2. Make a copy of the Valve Shim Replacement Chart, then tape the pages together, side-by-side.
3. Measure the valve clearances using the Go/No-Go method (see the note below). The clearances must be
- Intake valves: 0.25 mm +0.05 mm
- Exhaust valves: 0.30 mm +0.05 mm
NOTE:
- To measure with the Go/No-Go method, use two feeler gauges, one to measure the smallest allowable clearance, and the other to measure the largest.
- If the small gauge fits and the large gauge doesn't, the valve adjustment is OK.
- If the small gauge doesn't fit, or if the large gauge slides easily, the valve needs adjustment.
- The feeler gauges slide through the clearance gap at a slight angle, making the drag a little more than it would be on other engines.
4. For valves with the correct clearance, draw an "X" in the appropriate circle on the Valve Inspection Chart. For valves with incorrect clearances, write down the clearance you measured in the circle.
5. Rotate the camshaft pulley until the dual timing dots (exhaust camshaft) and single timing dot (intake camshaft) align with the timing dots on the camshaft drive gear.
6. Lock the camshaft gear to its subgear with a 5 x 0.5 mm bolt through either side of the hole in the gears. This holds the spring-loaded subgear in place so you can remove the camshaft. Do this for each camshaft you need to remove.
7. Remove the camshaft bearing caps, noting the location and direction of each cap.
8. Remove the camshaft(s).
9. For each valve needing adjustment, do steps 10 thru 13.
10. Insert a pick or a small screwdriver into the tappet notch, and pry out the shim.
11. Wipe oft the shim, then write its number on the Valve Inspection Chart for that valve and cylinder. If there is no number on the shim, measure its thickness with a micrometer, and write down the measurement on the Valve Inspection Chart.
12. Follow the directions on the Valve Shim Replacement Chart to select the correct shim.
13. Insert the correct shim, number side down, into the tappet. Make sure the shim is fully seated.
14. Install the camshafts (see steps 2 thru 9 of CAMSHAFT SUBGEAR PRELOADING, GEAR TIMING, AND CAMSHAFT INSTALLATION).
15. Rotate the camshaft pulleys a few turns to ensure the new shims are fully seated.
16. Recheck the clearances of the valves you adjusted with the Go/No-Go method (see step 3). If any clearances are incorrect, readjust them.
Valve Shims (While 41 shims are available, the 10 sizes will cover most valve adjustments):
Valve Inspection Chart
Valve Shim Replacement Chart