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How to Adjust Valves on a Four Cylinder Honda Car

How to Adjust Valves on a Four Cylinder Honda Car

By Dennis Bandy Copyright ©  



Honda Accord and Civic 4 Cyl Valve Adjustment
 
Typical valve clearance adjustment procedure for Honda Accord, Civic, Prelude etc. In most cases the engine needs to be under 100 degrees when the valve clearance is checked and adjusted. Remove the spark plug wires from the spark plugs, take the valve cover and upper timing cover off to allow the timing marks on the front of the cam sprocket to be seen. With a 1/2" ratchet rotate the crankshaft to the left (counter clockwise) so the number one piston is at top dead center. Remove the number one spark plug if needed to determine if the piston is at the top of it's bore. A long screwdriver in the spark plug hole while slowly turning the crank is an easy way to check this. Once the screwdriver reaches it's highest point and the "UP" on the camshaft pulley is straight up and the "TDC" marks are aligned with the head. The valves closest to the exhaust are the exhaust valves and the valves closest to the intake are the intake valves. The intake and exhaust valve clearance specifications can be found most of the time on the the white engine decal under the hood. Notice that a range is given, try to use the middle of this range if possible. 
 
Number One
Check the valve clearance with the feeler gauge for each valve for the number one cylinder, taking note if it is exhaust or intake since they have different specifications. If adjustment is needed loosen the lock nut and insert the feeler gauge, adjust the screw until the you feel a slight drag. The idea is to measure the gap accurately, if it is too loose or if the feeler is squeezed too tight, forcing the valve to open slightly against the force of the valve spring, the reading will not be accurate. With the feeler in place, hold the screw adjuster in place while tightening the jam nut. Recheck the clearance to make sure it did not move when tightening the jam nut.

 

Number Three
Rotate the crankshaft to the left (counter clock-wise) 180 degrees or a half turn, the cam will turn a quarter turn, 90 degrees. The "UP" mark should be pointed to the exhaust side of the engine. Check the valve clearance with the feeler gauge for each valve for the number three cylinder, again taking note if it is exhaust or intake since they have different specifications. If adjustment is needed loosen the lock nut and insert the feeler gauge, adjust the screw until the you feel a slight drag. Recheck the clearance to make sure it did not move when tightening the jam nut.
 
Number Four
Rotate the crankshaft to the left (counter clock-wise) 180 degrees or a half turn, the cam will turn a quarter turn, 90 degrees. The "UP" mark should be pointed down. Check the valve clearance with the feeler gauge for each valve for the number four cylinder, again taking note if it is exhaust or intake since they have different specifications. If adjustment is needed loosen the lock nut and insert the feeler gauge, adjust the screw until the you feel a slight drag. Recheck the clearance to make sure it did not move when tightening the jam nut.
 
Number Two
Rotate the crankshaft to the left (counter clock-wise) 180 degrees or a half turn, the cam will turn a quarter turn, 90 degrees. The "UP" mark should be pointed to the intake side. Check the valve clearance with the feeler gauge for each valve for the number two cylinder, again taking note if it is exhaust or intake since they have different specifications. If adjustment is needed loosen the lock nut and insert the feeler gauge, adjust the screw until the you feel a slight drag. Recheck the clearance to make sure it did not move when tightening the jam nut.
 
Tips
1. Don't rush the process take your time get it right before proceeding to the next step.
2. Use torque specifications, the jam nuts are small, usually 10 or 12 mm, avoid stripping them.
3. Consider replacing the valve cover gasket, use silicone on the corners where seams are located.
4. Valve adjustment specialty tools are not absolutely necessary (a screwdriver and and 10mm for most SOHC and a 12mm for most DOHC will do), however they do help to make the job a little easier.
5. Use an angled feeler gauge to allow easier insertion between the valve stem and the adjuster, if you only have a straight feeler it can be bent easily. 
 
 

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