Valve Clearance: Testing and Inspection
INSPECTIONCAUTION: Inspection and adjustment of valve clearance should be performed while engine is cold.
WARNING: INTAKE AND EXHAUST CAMSHAFTS FOR THIS DOHC ENGINE CAN BE INDEPENDENTLY ROTATED WITH TIMING BELTS REMOVED. AS CAN BE SEEN FROM THE FIGURE, IF INTAKE AND EXHAUST VALVES ARE LIFTED SIMULTANEOUSLY, THEIR HEADS WILL INTERFERE WITH EACH OTHER, RESULTING IN BENT VALVES.
- When timing belts are not installed, four camshafts are held at the "zero-lift" position, where all cams on camshafts do not push intake and exhaust valves down. (Under this condition, all valves remain un-lifted.)
- When camshafts are rotated to install timing belts, #2 intake and #4 exhaust cam of left-hand camshafts are held to push their corresponding valves down. (Under this condition, these valves are held lifted.) Right-side camshafts are held so that their cams do not push valves down.
- Left-hand camshafts must be rotated from the "zero-lift" position to the position where timing belt is to be installed at as small an angle as possible, in order to prevent mutual interference of intake and exhaust valve heads.
- Do not allow camshafts to rotate in the direction shown in the figure as this causes both intake and exhaust valves to lift simultaneously, resulting in interference with their heads.
1) Set the vehicle onto the lift.
2) Disconnect battery ground cable.
3) Remove canister (Taiwan spec. vehicles only).
4) Remove two bolts on the upper side which secure timing belt cover (RH).
5) Lift-up the vehicle.
6) Remove undercover (RH).
7) Remove canister bracket (Taiwan spec. vehicles only).
8) Loosen remaining bolt on under side which secures timing belt cover (RH), then remove belt cover.
9) Lower the vehicle.
10) Remove rocker cover.
- When inspecting #1 and #3 cylinders;
1) Disconnect connector from mass air flow sensor.
2) Loosen clamp which connects air intake duct to air intake chamber.
3) Remove the two clips from air cleaner upper cover.
CAUTION: Before installing air cleaner upper cover, align hole(s) with protruding portions of air cleaner lower case, then secure upper cover.
4) Disconnect blow-by hose from air intake duct.
5) Remove air intake duct and air cleaner upper cover as a unit.
6) Remove air cleaner element.
7) Remove air cleaner lower case.
8) Disconnect spark plug cords from spark plugs (#1 and #3 cylinders).
9) Place suitable container under the vehicle.
10) Disconnect PCV hose from rocker cover (RH).
11) Remove bolts, then remove rocker cover (RH).
- When inspecting # 2 and #4 cylinders;
1) Disconnect battery cables, and then remove battery and battery carrier.
2) Disconnect washer motor connectors.
3) Disconnect washer hoses from washer motors, then plug connections with suitable caps.
4) Remove washer tank.
5) Disconnect spark plug cords from spark plugs (#2 and #4 cylinders).
6) Remove under cover (LH).
7) Place suitable container under the vehicle.
8) Disconnect PCV hose from rocker cover (LH).
9) Remove bolts, then remove rocker cover (LH).
11) Turn crankshaft pulley clockwise until arrow mark on camshaft sprocket is set to position shown in figure.
12) Measure #1 cylinder intake valve and #3 cylinder exhaust valve clearances by using thickness gauge.
CAUTION:
- Insert the thickness gauge in as horizontal a direction as possible with respect to the shim.
- Measure exhaust valve clearances while lifting-up the vehicle.
Valve Clearance:
Intake: 0.20 ± 0.02 mm (0.0079 ± 0.0008 inch)
Exhaust: 0.25 ± 0.02 mm (0.0098 ± 0.0008 inch)
13) If necessary, adjust the valve clearance.
14) Further turn crankshaft pulley clockwise. Using the same procedures as in step 12) above, measure valve clearances.
1) Set arrow mark on camshaft sprocket to position shown in figure, and measure #2 cylinder exhaust valve and #3 cylinder intake valve clearances.
2) Set arrow mark on camshaft sprocket to position shown in figure, and measure #2 cylinder intake valve and #4 cylinder exhaust valve clearances.
3) Set arrow mark on camshaft sprocket to position shown in figure, and measure #1 cylinder exhaust valve and #4 cylinder intake valve clearances.
15) After inspection, install the related parts in the reverse order of removal.
ADJUSTMENT
CAUTION: Adjustment of valve clearance should be performed while engine is cold.
1) Measure all valve clearances.
NOTE: Record each valve clearance after it has been measured.
2) Remove shim of intake side.
1) Prepare the Special Tool (ST).
ST 498187100 SHIM REPLACER KIT
2) Rotate the notch of the valve lifter outward by 45°.
3) Set REPLACER No. 1 (A) to intake camshaft.
4) Set REPLACER No. 2 (B).
5) Set REPLACER No. 3 (C) to hole of REPLACER No. 1.
6) Rotate REPLACER No. 3 (C) until REPLACER No. 2 (B) pushes away valve lifter.
7) Insert tweezers into the notch of the valve lifter, and take the shim out.
3) Remove shim of exhaust side.
1) Prepare the ST.
ST 498187100 SHIM REPLACER KIT
2) Rotate the notch of the valve lifter outward by 45°.
3) Set REPLACER No. 1 (A) to exhaust camshaft.
4) Set REPLACER No. 2 (B).
5) Set REPLACER No. 3 (C) to hole of REPLACER No. 1.
6) Rotate REPLACER No. 3 until REPLACER No. 2 pushes away valve lifter.
7) Insert tweezers into the notch of the valve lifter, and take the shim out.
NOTE: By using a magnet, the shim can be taken out without dropping it.
4) Measure thickness of shim with micrometer.
5) Select a shim of suitable thickness using measured valve clearance and shim thickness, using the table.
S: Shim thickness to be used
V: Measured valve clearance
T: Shim thickness required
6) Set suitable shim selected in one step before, to valve lifter.
7) Turn crankshaft pulley clockwise until arrow mark on camshaft sprocket is set to position shown in figure.
8) Ensure that #1 cylinder intake valve and #3 cylinder exhaust valve are adjusted to specifications.
CAUTION:
- Insert the thickness gauge in as horizontal a direction as possible with respect to the shim.
- Adjust exhaust valve clearances while lifting-up the vehicle.
Valve Clearance:
Intake: 0.20 ± 0.02 mm (0.0079 ± 0.0008 inch)
Exhaust: 0.25 ± 0.02 mm (0.0098 ± 0.0008 inch)
9) Turn crankshaft two complete rotations. Check again to ensure that #1 cylinder intake valve and #3 cylinder exhaust valve clearances are within specifications. If necessary, re-adjust valve clearances.
10) Further turn crankshaft pulley clockwise. Using the same procedures as in two steps before, measure valve clearances.
1) Set arrow mark on camshaft sprocket to position shown in figure, and check #2 cylinder exhaust valve and #3 cylinder intake valve clearances.
2) Set arrow mark on camshaft sprocket to position shown in figure, and check #2 cylinder intake valve and #4 cylinder exhaust valve clearances.
3) Set arrow mark on camshaft sprocket to position shown in figure, and check #1 cylinder exhaust valve and #4 cylinder intake valve clearances.