Acura Coupes and Sedans 1994-2000 Repair Information

Valve Lash

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ADJUSTMENT 1.8L (B18B1, B18C1 and B18C5) Engines



While all valve adjustments must be as accurate as possible, it is better to have the valve adjustment slightly loose rather than too tight. Burned valves may result from overly tight adjustments. Perform the valve adjustment for each cylinder in the same sequence as the firing order: 1-3-4-2.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Be sure the engine is cold; cylinder head temperature must be below 100° F (38° C). Overnight cold is best.
  4.  
  5. Remove the cylinder head cover and the upper timing belt cover.
  6.  
  7. Set the No. 1 cylinder to Top Dead Center (TDC). The word UP should appear at the top and the TDC grooves on the pulley should align with the cylinder head surface or the mark on the rear belt cover.
  8.  
  9. Valve clearances are:
    1. B18B1 engine: Intake-0.003-0.005 in. (0.08-0.12mm), Exhaust-0.006-0.008 in. (0.16-0.20mm)
    2.  
    3. B18C1 and B18C5 Variable Valve Timing and Electronic Lift Control (VTEC) engine: Intake-0.006-0.007 in. (0.15-0.19mm), Exhaust-0.007-0.008 in. (0.17-0.20mm)
    4.  

  10.  

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Valve arrangement-1.8L (B18B1, B18C1, and B18C5) engines

  1. With the No. 1 cylinder at TDC, adjust the valves of the No. 1 cylinder by performing the following procedures:
    1. Hold the rocker arm against the valve and place the feeler gauge between the rocker arm and the camshaft lobe. There should be a slight drag on the feeler gauge.
    2.  
    3. If adjustment is required, loosen the valve adjusting the screw locknut.
    4.  
    5. Turn the adjusting screw to obtain the proper clearance.
    6.  
    7. Hold the adjusting screw and tighten the locknut(s) to 18 ft. lbs. (25 Nm).
    8.  
    9. Recheck the clearance.
    10.  

  2.  
  3. Turn the crankshaft 180 degrees counterclockwise; the cam pulley will turn 90 degrees. With the No. 3 cylinder at TDC, the UP marks should be at the exhaust side. Adjust the valves on the No. 3 cylinder.
  4.  

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Crankshaft pulley timing mark-1.8L engines

  1. Turn the crankshaft 180 degrees counterclockwise; the cam pulley will turn 90 degrees. With the No. 4 cylinder at TDC, both UP marks should be at the bottom. Adjust the valves on the No. 4 cylinder.
  2.  
  3. Turn the crankshaft 180 degrees counterclockwise. The No. 2 cylinder will now be on TDC and the UP marks should be at the intake side. Adjust the valves on the No. 2 cylinder.
  4.  
  5. Install the cylinder head cover and upper timing belt cover.
  6.  

2.3L Engine

The valve should be adjusted only when the engine temperature is below 100°F (38°C). Retighten the crankshaft pulley bolt to 181 ft. lbs. (245 Nm) after adjusting the valves.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Turn the crankshaft so the No. 1 piston is at Top Dead Center (TDC). Be sure the UP mark on the camshaft pulley is at the 12 o'clock position.
  4.  
  5. Adjust the valves on the No. 1 cylinder. To the following specifications:

    Intake-0.010 in. (0.26mm)
     
    Exhaust-0.012 in. (0.30mm)
     

  6.  
  7. Tighten the locknut to 14 ft. lbs. (20 Nm).
  8.  
  9. Turn the crankshaft counterclockwise 180degrees. Be sure the UP mark on the camshaft pulley is at the 9 o'clock position.
  10.  
  11. Adjust the valves on the No. 3 cylinder. Tighten the locknut to 14 ft. lbs. (20 Nm).
  12.  
  13. Turn the crankshaft counterclockwise 180 degrees. Be sure the UP mark on the camshaft pulley is at the 6 o'clock position.
  14.  
  15. Adjust the valves on the No. 4 cylinder. Tighten the locknut to 14 ft. lbs. (20 Nm).
  16.  
  17. Turn the crankshaft counterclockwise 180 degrees. Be sure the UP mark on the camshaft pulley is at the 3 o'clock position.
  18.  
  19. Adjust the valves on the No. 2 cylinder. Tighten the locknut to 14 ft. lbs. (20 Nm).
  20.  
  21. Retighten the crankshaft pulley bolt to 181 ft. lbs. (245 Nm) after adjusting the valves.
  22.  

2.5L Engine

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the cylinder head cover and the upper timing belt cover.
  6.  
  7. Rotate the crankshaft to align the white Top Dead Center (TDC) on the crankshaft pulley with the pointer on the cover. Be sure the UP mark on the camshaft sprocket is up and the TDC marks align with the edge of the cylinder head.
  8.  
  9. Align the No. 1 mark on the back of the camshaft sprocket with the notch in the camshaft holder.
  10.  
  11. Hold a No. 1 cylinder rocker arm against the camshaft and use a feeler gauge to check the clearance at the valve stem. Intake valve clearance should be 0.010 in. (0.26mm), exhaust valve clearance should be 0.012 in. (0.30mm). The service limit for both intake and exhaust valves is plus or minus 0.0008 in. (0.02mm). Loosen the locknut and turn the adjusting screw to adjust the clearance. Tighten the locknut and recheck the clearance.
  12.  
  13. Rotate the crankshaft counterclockwise to align the TDC marks for each piston with the notch. Adjust the valves of each cylinder. The adjustment order is 1, 2, 4, 5 and 3.
  14.  
  15. Install the cylinder head and timing belt covers.
  16.  
  17. Reconnect the negative battery cable.
  18.  

3.0L Engine See Figures 3 and 4

Click image to see an enlarged view

Fig. Fig. 3: Adjusting screw locations for valve lash adjustment-3.0L engine



Click image to see an enlarged view

Fig. Fig. 4: Slide the feeler gauge between the valve and rocker arm while turning the adjusting screw-3.0L engine

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove the cylinder head cover.
  4.  
  5. Remove the upper front timing belt cover.
  6.  
  7. Rotate the crankshaft so the No. 1 piston is at Top Dead Center (TDC) on compression to adjust the valves for the No. 1 cylinder.
  8.  
  9. Loosen the locknuts and adjust the screws until a slight drag can be felt with the feeler gage when the gage is placed between the valve and rocker arm tip as shown. The specifications are as follows:

    Intake-0.006-0.007 in. (0.15-0.18mm)
     
    Exhaust-0.007-0.008 in. (0.18-0.20mm)
     

  10.  
  11. Rotate the crankshaft clockwise until the No. 4 on the camshaft sprocket is near the pointer on the rear cover. This is the No. 4 cylinder firing position.
  12.  

See Figure 5

Click image to see an enlarged view

Fig. Fig. 5: Camshaft sprocket position when No. 1 piston is at TDC-3.0L engine

  1. Adjust the valves for the No. 4 cylinder while the sprocket is in this position. Tighten the locknuts to 14 ft. lbs. (20 Nm).
  2.  
  3. Continue to rotate the crankshaft and adjust the valves for each cylinder in this manner.
  4.  
  5. Install the timing belt and cylinder head covers.
  6.  

3.2L and 3.5L Engines

These engines are equipped with hydraulic valve lash adjusters on the rocker arms. No valve clearance adjustments are possible or necessary.

 
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