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Toyota Supra JZA80

Valve clearance

Inspect and adjust the valve clearance when the engine is cold.
  1. Remove throttle body and intake air connector assembly (See page SF-19)
  2. Disconnect high-tension codes (See page IG-8 )
  3. Remove No.3, No.1 and No.2 cylinder head covers
    1. Remove the 4 bolts, 4 nuts and No.3 cylinder head cover.
    2. Remove the 4 bolts, No.1 cylinder head cover and gasket.
    3. Remove the 4 bolts, No.2 cylinder head cover and gasket.
  4. Set No.1 cylinder to TDC/compression
    1. Turn the crankshaft pulley and align its groove with the timing mark ”0” of the No.1 timing belt cover.
      Always turn the crankshaft clockwise.
    2. Check that the timing marks of the camshaft timing pulleys are aligned with the timing marks of the No.4 timing belt cover.
      If not, turn the crankshaft 1 revolution (360°).
  5. Inspect valve clearance
    1. Check only those valves indicated in the illustration.
      • Using a feeler gauge, measure the clearance between the valve lifter and camshaft.
      • Record the valve clearance measurements of those that are out of specification. They will be used later to determine the required replacement adjusting shim.
      Valve clearance (Cold):
      • Intake 0.15 - 0.25 mm (0.006 - 0.010 in.)
      • Exhaust 0.25 - 0.35 mm (0.010 - 0.014 in.)
    2. Turn the crankshaft pulley 1 revolution (360°), and align the groove with timing mark ”O” of the No.1 timing belt cover.
    3. Check only the valves indicated as shown. Measure the valve clearance. (See procedure in step (a))
  6. Adjust valve clearance
    1. Remove the adjusting shim.
      • Turn the camshaft so that the cam lobe for the valve to be adjusted faces up.
      • Turn the valve lifter with a screwdriver so that the notches are perpendicular to the camshaft.
      • Using SST (A), hold the camshaft as shown in the illustration.
        SST 09248–55040 (09248–05410)
      • Using SST (A), press down the valve lifter and place SST (B) between the camshaft and valve lifter. Remove SST (A).
        SST 09248–55040 (09248–05410, 09248–05420)
        • Apply SST (B) at slight angle on the side marked with ”7” or ”9”, at the position shown in the illustration.
        • Insert SST (B) gently from the inside as shown in the illustration.
        • Using a small screwdriver and a magnetic finger, remove the adjusting shim.
    2. Determine the replacement adjusting shim size according to the following Formula or Charts:
      • Using a micrometer, measure the thickness of the removed shim.
      • Calculate the thickness of a new shim so the valve clearance comes within specified value.
        T ......... Thickness of used shim
        A ......... Measured valve clearance
        N ......... Thickness of new shim
        Intake
        N = T + (A - 0.20 mm (0.008 in.))
        Exhaust
        N = T + (A - 0.30 mm (0.012 in.))
      • Select a new shim with a thickness as close as possible to the calculated values.
      Shims are available in 17 sizes in increments of 0.050 mm (0.0020 in.), from 2.500 mm (0.0984 in.) to 3.300 mm (0.1299 in.).
    3. Install a new adjusting shim.
      • Place a new adjusting shim on the valve lifter, with imprinted numbers facing down.
      • Press down the valve lifter with SST (A), and remove SST (B).
        SST 09248–55040
    4. Recheck the valve clearance.
  7. Reinstall No.1, No.2 and No.3 cylinder head covers
    1. Remove any old packing (FIPG) material.
    2. Apply seal packing to the cylinder head as shown in the illustration.
      Seal packing:
      Part No. 08826-00080 or equivalent
    3. Install the gaskets to the No.1 and No.2 cylinder head covers.
    4. Install the No.1 cylinder head cover with the 4 bolts.
      Torque: 8.3 N·m (85 kgf·cm, 74 in.·lbf)
    5. Install the No.2 cylinder head cover with the 4 bolts.
      Torque: 8.3 N·m (85 kgf·cm, 74 in.·lbf)
    6. Install the No.3 cylinder head cover with the 4 bolts and 4 nuts.
      Torque: 8.3 N·m (85 kgf·cm, 74 in.·lbf)
  8. Reconnect high-tension codes to cylinder head covers (See page IG-10 )
  9. Reinstall throttle body and intake air connector assembly (See page SF-25 )

Adjusting Shim Selection Chart (Intake)

Intake valve clearance (Cold):
0.15 - 0.25 mm (0.006 - 0.010 in.)

The 2.800 mm (0.1102 in.) shim is installed, and the measured clearance is 0.450 mm (0.0177 in.)
Replace the 2.800 mm (0.1102 in.) shim with a new No.12 shim.
New shim thickness mm (in.)
Shim
No.
Thickness
1 2.500 (0.0984)
2 2.550 (0.1004)
3 2.600 (0.1024)
4 2.650 (0.1043)
5 2.700 (0.1063)
6 2.750 (0.1083)
7 2.800 (0.1102)
8 2.850 (0.1122)
9 2.900 (0.1142)
10 2.950 (0.1161)
11 3.000 (0.1181)
12 3.050 (0.1201)
13 3.100 (0.1220)
14 3.150 (0.1240)
15 3.200 (0.1260)
16 3.250 (0.1280)
17 3.300 (0.1299)
New shims have the thickness in millimeters imprinted on the face.

Adjusting Shim Selection Chart (Exhaust)

Exhaust valve clearance (Cold):
0.25 - 0.35 mm (0.010 - 0.014 in.)

The 2.800 mm (0.1102 in.) shim is installed, and the measured clearance is 0.450 mm (0.0177 in.)
Replace the 2.800 mm (0.1102 in.) shim with a new No.10 shim.
New shim thickness mm (in.)
Shim
No.
Thickness
1 2.500 (0.0984)
2 2.550 (0.1004)
3 2.600 (0.1024)
4 2.650 (0.1043)
5 2.700 (0.1063)
6 2.750 (0.1083)
7 2.800 (0.1102)
8 2.850 (0.1122)
9 2.900 (0.1142)
10 2.950 (0.1161)
11 3.000 (0.1181)
12 3.050 (0.1201)
13 3.100 (0.1220)
14 3.150 (0.1240)
15 3.200 (0.1260)
16 3.250 (0.1280)
17 3.300 (0.1299)
New shims have the thickness in millimeters imprinted on the face.
This guide is based on the book edition Toyota (RM502U, 1997)

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