How to Adjust Valves on Honda Civicby William Zane
A valve adjustment is a routine tune-up procedure on all cars, including a Honda Civic. If the valves are severely out of adjustment, it can make a car run poorly and even make an engine stop running entirely. And though a valve adjustment sounds intimidating, it’s actually not that difficult with the right tools and approach. Valve adjustments for different models are usually labeled on a sticker in the engine bay, or the workshop manual will list them.
Remove the spark plug wires from the spark plugs. Remove the valve cover and the upper timing chain cover so that you can see the timing marks on the camshaft sprocket.
Rotate the engine with a 1/2-inch socket on the crank bolt so that the number one piston is at top dead center (TDC). You can remove the number one spark plug to determine if the piston is at TDC. Insert a long screwdriver into the spark plug hole while slowly turning the crank. TDC is where the screwdriver (and therefore the piston) is at the highest point before the piston starts to go back down. At this point, the camshaft pulley should be pointing straight up and the “TDC” marks aligned with the marks on the head. You can also shine a flashlight into the spark plug hole to visually confirm that the piston is at the top of its travel.
Check the valve clearance for each valve (intake and exhaust) for the number one cylinder. Loosen the lock nut that holds the adjuster in place, insert a feeler gauge of the proper thickness between the valve stem and the clearance adjuster and then tighten the lock nut over the feeler gauge until you feel it drag slightly on the feeler gauge. Hold the adjuster in place by placing a flat-head screwdriver into the slot on top of the adjuster while you tighten the lock nut with a wrench. The correct clearance will allow you to remove the feeler gauge, but you will feel resistance as you pull the gauge out. If you cannot remove the feeler gauge, the setting is too tight; if you can move the gauge easily, it is too loose. The intake and exhaust valves have different settings, so consult your manual for the proper settings.
Check the valves for the number three piston. Rotate the crankshaft counterclockwise (to the left) 180-degrees, which is half of a turn. The camshaft should turn a quarter of a turn. The “UP” mark on the camshaft pulley will be pointing towards the exhaust side of the motor. Check the clearance for the intake and exhaust valve in the same manner that was described in Step 3.
Check the valves for the number four piston. Turn the crankshaft counterclockwise a half a turn. The cam will turn another quarter turn. The “UP” mark on the crankshaft pulley will now be pointing down. Check the clearance for the intake and exhaust valve in the same manner that was described in Step 3.
Check the valves for the number two piston. Rotate the crankshaft another half turn counterclockwise; the camshaft will turn a quarter turn. The “UP” mark will now be pointing to the intake side of the motor. Check the clearance for the intake and exhaust valve in the same manner that was described in Step 3.
Replace the timing chain cover, valve cover and spark plug wires.
- When adjusting the valves, it is highly recommended that you replace the valve cover gasket to avoid having leaks later on.
Things You'll Need
- Socket set and ratchet
- Open-ended wrenches
- Feeler gauges
- Flat-head screwdriver
William Zane has been a freelance writer and photographer for over six years and specializes primarily in automotive-related subject matter among many other topics. He has attended the Academy of Art College in San Francisco, where he studied automotive design, and the University of New Mexico, where he studied journalism.