Honda CRX silhouetteCRX

Engine Tune-up — Valve Clearance Adjustment

5-8prose procedure

Valve clearance procedure for the SOHC engine (D16A6/D16A7). DOHC engine procedure is covered separately.

Valve Clearance Adjustment

SOHC Engine:

  1. 1
    Remove valve cover.
    Top view of the SOHC cylinder head valve train identifying the INTAKE valves (No.4, No.3, No.2, No.1) along the top and the EXHAUST valves (No.4, No.3, No.2, No.1) along the bottom.
  2. 2
    Set No. 1 piston at TDC. "UP" mark on the pulley should be at top, and TDC grooves on the pulley should align with cylinder head surface. The distributor rotor must be pointing towards No. 1 plug wire.
    Number 1 piston at TDC: timing-belt pulley showing the "UP" MARK at top and the TDC GROOVES aligned with the cylinder head surface.
  3. 3
    Adjust valves on No.1 cylinder. Intake: 0.17-0.22 mm (0.007-0.009 in.). Exhaust: 0.22-0.27 mm (0.009-0.011 in.).
  4. 4
    Loosen locknut and turn adjustment screw until feeler gauge slides back and forth with slight amount of drag.
    Close-up of valve adjustment showing the feeler gauge, adjustment screw and locknut, with torque callout for the locknuts.
  5. 5
    Tighten locknut and check clearance again. Repeat adjustment if necessary.
  6. 6
    Rotate crankshaft 180° counterclockwise (cam pulley turns 90°). The "UP" mark should be at exhaust side. Distributor rotor should point to No. 3 plug wire. Adjust valves on No. 3 cylinder.
    Number 3 piston at TDC: timing-belt pulley showing the "UP" MARK pointing to the exhaust side and the GROOVES.
  7. 7
    Rotate crankshaft 180° counterclockwise to bring No. 4 piston to TDC. Both TDC grooves are once again visible and distributor rotor points to No.4 plug wire. Adjust valves on No.4 cylinder.
    Number 4 piston at TDC: timing-belt pulley showing the "UP" MARK and both TDC GROOVES visible.
  8. 8
    Rotate crankshaft 180° counterclockwise to bring No. 2 piston to TDC. The "UP" mark should be at intake side. Distributor rotor should point to No. 2 plug wire. Adjust valves on No. 2 cylinder.
    Number 2 piston at TDC: timing-belt pulley showing the "UP" MARK pointing to the intake side and the GROOVES.

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