Honda Accord/Prelude 1984-1995 Repair Guide

General Information

Print

Periodic valve lash adjustment is not necessary on the Accord V-6. These engines are equipped with hydraulic tappets which automatically take up valve clearance during engine temperature changes and component wear. The adjusting nuts and screws on the exhaust rocker arms are provided for initial adjustment of the pushrods after cylinder head service. Please refer to Engine & Engine Overhaul for procedures.

As part of every major tune-up or service interval, the valve clearance should be checked and adjusted if necessary.

If the valve clearance is too large, part of the lift of the camshaft will be used up in removing the excessive clearance, thus the valves will not be opened far enough. This condition makes the valve train noisy as they take up the excessive clearance. The engine will perform poorly, since a smaller amount of air/fuel mixture will be admitted to the cylinders. The exhaust valves will not open far enough to vent the cylinder completely; retained pressure (back pressure) will restrict the entry of the next air/fuel charge.

If the valve clearance is too small, the intake and exhaust valves will not fully seat on the cylinder head when they close. This causes internal cylinder leakage and prevents the hot valve from transferring some heat to the head and cooling off. Therefore, the engine will run poorly (due to gases escaping from the combustion chamber), and the valves will overheat and burn (since they cannot transfer heat unless they are firmly touching the seat in the cylinder head).

While all valve adjustments must be as accurate as possible, it is better to have the valve adjustment slightly loose than slightly tight, as burnt valves may result from overly tight adjustments.

ADJUSTMENT



See Figures 1 and 2

Valve lash must always be adjusted with the engine cold. The head temperature must be below 100°F (38°C). Generally, this means allowing the engine to cool for at least 3 hours after driving. Overnight cold is best. If the valve adjustment is being performed as part of a routine maintenance or mileage service regimen, do it before the engine is warmed up to check timing or idle.



Click image to see an enlarged view

Fig. Fig. 1: If the feeler gauge passes with no drag or cannot be inserted, hold the adjusting screw with a screwdriver, then loosen the locknut



Click image to see an enlarged view

Fig. Fig. 2: Turn the adjusting screw to obtain the proper clearance, then tighten the locknut to its proper specification

Valve location will vary with the type of engine. As a guide, the intake valves always are aligned with the ports or runners of the intake manifold. The exhaust valves align with the tubes of the exhaust manifold.

Adjusting the valves requires positioning No. 1 cylinder at TDC, then rotating the engine to certain other precise positions. Rotate the engine with a socket on the crankshaft pulley. (The crank pulley is the lowest pulley on the engine.) This engine rotation is much easier if the spark plugs are removed before hand, eliminating the compression from the cylinders. Always rotate the engine in a counterclockwise direction as viewed from the pulley end.

If you miss a mark during the rotation, keep going in the same direction until it comes around again. Turning the engine backwards may cause the timing belt to jump a tooth or slacken, risking engine damage when restarted. Remember that cylinder No. 1 is the one closest to the pulley end of the engine.

The engine is at TDC No. 1 if ALL of the following are true:



The TDC mark on the flywheel or flexplate is aligned with the pointer in the timing inspection window at the rear of the engine. The TDC mark is generally white; it is never red
 
The distributor rotor is pointing at cap terminal or plug wire No. 1. Mark the cap with the corresponding wire numbers, then lift the cap check the rotor position
 
The alignment marks on the camshaft pulley are positioned as indicated in the individual procedure
 
The rocker arms for at least one of the valves on cylinder No. 1 is loose; the points or lobes of the cam are not putting pressure on the rocker arms
 

1984-89 Accord, 1984-87 Prelude and 1988-90 SOHC Prelude

See Figures 3, 4, 5 and 6

All engines in these vehicles use a Single Overhead Camshaft (SOHC) that operates the valves. The engines used in 1984-85 Accords use 2 intake valves, 1 exhaust and 1 auxiliary intake valve per cylinder. The auxiliary valves are located on the exhaust side and are smaller than the other valves. The other vehicles use the same arrangement without the auxiliary intake valve.



Click image to see an enlarged view

Fig. Fig. 3: Valve placement on 1984-85 Accords

Clearances for the valves are:



Intake, including auxiliary valve on 1984-85 Accord: 0.005-0.007 in. (0.12-0.17mm)
 
Exhaust: 0.010-0.012 in. (0.25-0.30mm)
 

  1. With the ignition OFF , remove the valve cover.
  2.  
  3. Set the engine to TDC No. 1 cylinder. The UP mark or dot on the camshaft pulley should be at the top of the pulley. The two grooves on the back (valve) side of the pulley should both be visible and aligned with the surface of the cylinder head. The distributor rotor points to No. 1 terminal or wire.
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Position of the engine at TDC for cylinder No. 1; SOHC engines 1984-89

  1. Check the clearance on all the valves for cylinder No. 1 with a flat feeler gauge inserted between the tip of the valve and the contact surface of the rocker. The gauge should pass the gap with slight drag.
  2.  
  3. If the gauge passes with no drag or cannot be inserted, adjust as follows:
    1. Loosen the adjusting screw locknut.
    2.  
    3. Turn the adjusting screw to obtain the proper clearance.
    4.  
    5. Hold the adjusting screw in position and tighten the locknut. Correct locknut torque is 14 ft. lbs. (20 Nm), except on auxiliary valves which are 10 ft. lbs. (14 Nm). After the locknut is tightened, recheck the clearance and readjust as necessary.
    6.  

  4.  
  5. Rotate the crankshaft 180 degrees (the camshaft will turn 90 degrees). One of the grooves in the pulley is now vertical and aligned with the indented mark on the timing belt cover. The UP mark or dot is not visible and the distributor rotor points to terminal or wire No. 3.
  6.  



Click image to see an enlarged view

Fig. Fig. 5: Markers for correct positioning of pistons 3, 4 and 2



Click image to see an enlarged view

Fig. Fig. 6: Valve placement on 1986-89 Accord and SOHC Prelude to 1990

  1. Check all the valves for cylinder No. 3, repeating the adjusting steps previously described as necessary.
  2.  
  3. Rotate the crankshaft 180 degrees. Both grooves on the cam pulley are visible and aligned with the head surfaces. The distributor rotor points to terminal or wire No. 4.
  4.  
  5. Check all the valves for cylinder No. 4, repeating the adjusting steps previously described as necessary.
  6.  
  7. Rotate the crankshaft 180 degrees. One groove on the pulley is again vertical, aligned with the indentation on the timing belt cover. The UP mark or dot is visible, but is not at the top. The distributor rotor points to terminal or wire No. 2.
  8.  
  9. Check all the valves for cylinder No. 2, repeating the adjusting steps previously described as necessary.
  10.  
  11. Reinstall the valve cover.
  12.  

1990-95 Accord and 1992-95 SOHC Prelude

See Figures 7 and 8

The engines in these cars use 2 intake valves and 2 exhaust valves per cylinder.

Valve clearances for the valves are:



Intake: 0.009-0.011 in. (0.24-0.28mm)-0.10 in. (0.26mm) preferred
 
Exhaust: 0.011-0.013 in. (0.28-0.32mm)-0.012 in. (0.30mm) preferred.
 



Click image to see an enlarged view

Fig. Fig. 7: Valve placement on 1990-95 Accords and 1992-95 SOHC Preludes

  1. With the ignition OFF , remove the valve cover.
  2.  
  3. Set the engine to TDC No. 1 cylinder. The UP mark on the camshaft pulley should be at the top of the pulley. The two grooves on the side of the pulley should both be visible and aligned with the surface of the cylinder head. The distributor rotor points to No. 1 terminal or wire.
  4.  



Click image to see an enlarged view

Fig. Fig. 8: Camshaft pulley marks on 1990-95 Accords and 1992-95 SOHC Preludes. TDC on the No. 1 cylinder shown

  1. Check the clearance on all the valves for cylinder No. 1 with a flat feeler gauge inserted between the tip of the valve and the contact surface of the rocker. The gauge should pass the gap with slight drag.
  2.  
  3. If the gauge passes with no drag or cannot be inserted, adjust as follows:
    1. Loosen the adjusting screw locknut.
    2.  
    3. Turn the adjusting screw to obtain the proper clearance.
    4.  
    5. Hold the adjusting screw in position and tighten the locknut. Correct locknut torque is 14 ft. lbs. (20 Nm). After the locknut is tightened, recheck the clearance and readjust as necessary.
    6.  

  4.  
  5. Rotate the crankshaft 180 degrees (the camshaft will turn 90 degrees). One of the grooves in the pulley is now vertical and aligned with the indented mark on the timing belt cover. The UP mark is now at the exhaust side and the distributor rotor points to terminal or wire No. 3.
  6.  
  7. Check all the valves for cylinder No. 3, repeating the adjusting steps previously described as necessary.
  8.  
  9. Rotate the crankshaft 180 degrees. Both grooves on the cam pulley are visible and aligned with the head surfaces. The distributor rotor points to terminal or wire No. 4. The UP mark is upside down or at the bottom of the cam pulley.
  10.  
  11. Check all the valves for cylinder No. 4, repeating the adjusting steps previously described as necessary.
  12.  
  13. Rotate the crankshaft 180 degrees. One groove on the pulley is again vertical, aligned with the indentation on the timing belt cover. The UP mark is at the intake side. The distributor rotor points to terminal or wire No. 2.
  14.  
  15. Check all the valves for cylinder No. 2, repeating the adjusting steps previously described as necessary.
  16.  
  17. Reinstall the valve cover.
  18.  

1988-95 DOHC Prelude

See Figures 9, 10, 11, 12 and 13

These engines employ Dual Overhead Camshafts (DOHC) and use 4 valves per cylinder (2 intake and 2 exhaust). The intake valves are operated by one cam and the exhaust valves by the other. Valve adjustment on these engines is similar to other engines. Each camshaft pulley has UP or arrow marks and grooves; when the engine is rotated during the adjustment, the marks must be aligned both with the cylinder head and with each other.

Valve clearances for 1988-91 Preludes are:



Intake: 0.003-0.005 in. (0.08-0.12mm)
 
Exhaust: 0.006-0.008 in. (0.16-0.20mm)
 

Valve clearances for 1992 Preludes are:



Intake: 0.004-0.005 in. (0.09-0.13mm)
 
Exhaust: 0.006-0.007 in. (0.15-0.19mm)
 

Valve clearances for 1993-95 Preludes without VTEC are:



Intake: 0.003-0.004 in. (0.07-0.11mm)
 
Exhaust: 0.006-0.007 in. (0.15-0.19mm)
 

Valve clearances for 1993-95 Preludes with VTEC are:



Intake: 0.006-0.007 in. (0.15-0.19mm)
 
Exhaust: 0.007-0.008 in. (0.17-0.21mm)
 

  1. With the ignition OFF , remove the valve cover.
  2.  
  3. Set the No. 1 piston at top dead center (TDC). The UP or arrow marks on the pulleys should be at the top, and the TDC grooves on the edge or side of the pulley should align with the cylinder head surface. The distributor rotor should be pointing towards the No. 1 spark plug wire.
  4.  
  5. Check the clearance on all the valves for cylinder No. 1 with a feeler gauge. The gauge should pass the gap with slight drag.
  6.  



Click image to see an enlarged view

Fig. Fig. 9: Valve placement on DOHC Preludes to 1991



Click image to see an enlarged view

Fig. Fig. 10: Valve placement on 1992-95 DOHC Preludes



Click image to see an enlarged view

Fig. Fig. 11: Positioning the engine at TDC for No. 1 cylinder



Click image to see an enlarged view

Fig. Fig. 12: On DOHC engines, pass the feeler gauge under the cam lobe to check the valve clearance

  1. If the gauge passes with no drag or cannot be inserted, adjust as follows:
    1. Loosen the adjusting screw locknut.
    2.  
    3. Turn the adjusting screw to obtain the proper clearance.
    4.  
    5. Hold the adjusting screw in position and tighten the locknut. Correct locknut torque is 20 ft. lbs. (27 Nm) on models without VTEC and 14 ft. lbs. (20 Nm) on models with VTEC. After the locknut is tightened, recheck the clearance and readjust as necessary.
    6.  

  2.  
  3. Rotate the crankshaft 180 degrees counterclockwise (the cam pulley will turn 90 degrees). The UP or arrow marks should be at the exhaust side. The distributor rotor should point to the number three spark plug wire. At this point the valves on No. 3 cylinder can be checked. Repeat the adjusting steps previously described as necessary.
  4.  
  5. Rotate the crankshaft 180 degrees counterclockwise to bring the No. 4 piston up to TDC. Both UP or arrow marks should be at the bottom and the distributor rotor should point to the number four spark plug wire. The grooves on the pulley align with the cylinder head surface and with each other. Check the valves for cylinder No. 4. Repeat the adjusting steps previously described as necessary.
  6.  
  7. Rotate the crankshaft 180 degrees counterclockwise to bring the No. 2 cylinder up to TDC. The UP or arrow marks should be at the intake side. The distributor rotor should point at the number two spark plug wire. Check all the valves for cylinder No. 2, repeating the adjusting steps previously described as necessary.
  8.  
  9. Once all the valves have been adjusted and rechecked, reinstall the valve cover on the engine. Reinstall the distributor cap. Start the engine and check for oil leaks.
  10.  



Click image to see an enlarged view

Fig. Fig. 13: Marker positions for setting cylinders 3, 4 and 2 at TDC; DOHC engines

 
label.common.footer.alt.autozoneLogo