How to Adjust Valves on Cars

by Contributing Writer

The valves on your Honda car. This corrects valve lash that may increase due to wear on the camshaft lobes and rocker arms. The results of this adjustment can be dramatic. Improved throttle response and power are common. Many companies make specialized tools for adjusting the valves on this and other engines, but this project can be completed by the average home mechanic without specialized tools. You should be able to complete the task in a couple of hours.

Under The Hood:

 How to Adjust Valves on a Shovelhead Harley Davidson

Remove original pushrods, with a screwdriver, by removing the retainer clips that hold the cover tubes in place. Then remove the cover tubes. As you are sitting on the motorcycle, the tubes containing the pushrods are located on the right-hand side of the engine, behind the air-cleaner.

Screw the pushrods, by hand, as far into the tubes as possible. Once you have adjusted pushrods to their shortest length, rotate the engine by placing the motorcycle on a jack and turning the rear wheel with the transmission in fourth gear, for ease of turning. Rotate the engine until at least one lobe of the cam sits at the lowest lift point. Tighten the pushrod until you are able to turn it from side to side, but there is zero lash, or up and down movement.

Tighten the pushrod locknut with two 7/16-inch wrenches for solid lifters. If your lifters are hydraulic, turn the pushrods longer by three and a half to four full turns before tightening the locknut.

Items you will need

  • Screwdriver

  • Jack

  • 2 wrenches, 7/16-inch

 How to Adjust Valves for a 1995 Nissan Truck

Run the engine to warm it thoroughly. Although valves can be adjusted cold, the manufacturer's specifications are for a hot engine and if they are adjusted cold, they will have to be rechecked hot and possibly readjusted.

Remove the air cleaner, spark plug wires and their supports from the rocker arm cover. Use a spark plug boot puller to remove the wires, so that they are not damaged.

Use a screwdriver to disconnect the brake booster vacuum hose and move it to the side for access.

Remove the bolts from the rocker arm cover, with a ratchet and socket. If the cover is stuck to the head, bump it with a wood block and a hammer to loosen it. Do not use a pry bar or you risk damaging the sealing surfaces of the head and cover, leading to future oil leaks.

Ensure that the parking brake is engaged and the transmission in neutral. Remove the coil wire from the center of the distributor cap and ground it to the engine block, using a jumper wire with alligator clips.

Note the position on the distributor cap and the No. 1 spark plug wire, and mark it on the distributor body. Remove the cap and set it aside.

Attach a large socket with a breaker bar to the bolt at the front of the crankshaft pulley and turn the crankshaft clockwise until the notch in the pulley lines up to the "0" mark on the timing plate. The objective is to bring the No. 1 piston to top dead center on the compression stroke.

Check the distributor rotor to ensure that it is pointing directly at the mark you made earlier on the distributor body. If is pointing to the No. 4 plug, it is on the exhaust stroke and you will have to keep turning one more full turn (360 degrees), until it comes back around on the compression stroke.

Check the rotor again to ensure you are on the proper stroke, and then you can proceed to check and adjust valve clearances for the 1, 2, 4 and 6 valves.

Insert a 0.012 inch (0.30 millimeter) feeler gauge between the adjuster screw and the valve stem. If the gauge fits with a slight drag, there is no adjustment necessary. If adjustment is necessary, loosen the screw's lock nut and adjust the screw as necessary, and then re-secure the lock nut. Recheck the clearance afterward to ensure that it did not change and repeat this procedure for each of the 1, 2, 4 and 6 valves.

Turn the crankshaft nut one more complete revolution to bring the No. 4 piston to top dead center on the compression stroke. From this position, you can adjust the 3, 5, 7 and 8 valves in the same manner as the other four.

Use a gasket scraper to remove the old gasket material from the head and rocker cover sealing surfaces, cleaning them thoroughly. Apply a continuous bead of sealant to the mating surface of the rocker cover, taking care to apply it also to the inside of the mounting bolt holes.

Place the new rocker cover gasket on top of the head, lining up all the holes, and install the rocker cover on top of it. Install the mounting bolts securely, while the sealant is still wet.

Reinstall the rest of the components removed, beginning with the distributor cap and spark plugs and ending with the air cleaner.

Items you will need

  • Spark plug boot puller

  • Screwdriver set

  • Ratchet

  • Socket set

  • Jumper wire with alligator clips

  • Breaker bar

  • Block of wood

  • Hammer

  • Feeler gauge set

  • Gasket scraper

  • Silicone sealant

 How to Adjust Valves on Honda Civic

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.

Items you will need

  • Socket set and ratchet

  • Open-ended wrenches

  • Feeler gauges

  • Flat-head screwdriver

 How to Adjust the Valves on a 1992 Honda Accord 2.2

Start with a cold engine. The manufacturer recommends that the engine be under 100 degrees Fahrenheit when making this adjustment.

Unplug the spark-plug wires from the spark plugs. Remove the the two 10 mm nuts that attach the valve cover to the cylinder head using a 10 mm socket and ratchet. Remove the four 10 mm bolts that attach the upper timing-belt cover to the valve cover and cylinder head using a 10 mm socket and ratchet. Set the timing cover and valve cover aside.

Rotate the engine counterclockwise, until the timing mark on the crankshaft pulley lines up with the pointer on the front of the lower timing cover, using a 1/2-inch drive ratchet and a 19 mm socket.

Check valve clearance on the number-one cylinder by slipping the correct thickness feeler gauge between the valve and the rocker arm. Exhaust valves should have a clearance between .009 and .011, and intake valves should be between .007 and .009. The exhaust valves are the valves closest to the exhaust system, and the intake valves are the valves closest to the intake manifold. To adjust the valve clearance, loosen the 12 mm jam nut on the adjuster and tighten or loosen the adjuster using a screwdriver. Tighten the jam nut while holding the adjuster still with the screwdriver.

Rotate the engine counterclockwise 180 degrees using the 1/2-inch drive ratchet and 19 mm socket. Check and adjust the valves on the number-three cylinder in the same manner as the number-one cylinder valves were adjusted. Rotate the engine again, 180 degrees counterclockwise, and adjust the number-four cylinder valves as needed. Rotate the engine again, 180 degrees counterclockwise, and adjust the number-two cylinder valves as needed

Items you will need

  • Socket set

  • Wrench set

  • Feeler-gauge set

  • New valve-cover gasket

 How to Adjust Valves in a Honda Accord

Remove the 10mm bolts that attach the valve cover to the cylinder head and the timing cover. Remove the valve cover and valve cover gasket from the cylinder head, and remove the upper timing cover from the engine. Remove the spark plugs.

Rotate the engine to top dead center on the number one cylinder compression stroke. Place a finger into the spark plug opening in the cylinder head and feel the compression as the engine nears top dead center to verify it is on the compression stroke. Stop when the timing mark on the crankshaft pulley indicates top dead center. The timing mark/pointer on the camshaft pulley will be straight up.

Refer to the service manual for the valve clearance specifications for your specific year and model. The specifications changed from engine to engine, and year to year. Valve clearance specifications are also listed on the emissions tag under the hood. Note that the clearance for the exhaust valves is not the same as the clearance for the intake valves. Slip the correct thickness feeler gauge under the valve rocker arm. Loosen the lock nut, and tighten the adjuster screw until there is a slight drag on the feeler gauge as it is moved. Tighten the lock nut, and check the clearance again. It is not unusual for the adjuster screw to tighten as the lock nut tightens, so it may take a few tries to get it right. Adjust both the intake and exhaust valves on the number one cylinder.

Rotate crankshaft 180 degrees counterclockwise. The camshaft will turn 90 degrees, and the timing mark/pointer on the cam gear will be 90 degrees from straight up. Adjust the valves, intake and exhaust, on the number three cylinder.

Rotate the crankshaft an additional 180 degrees; the cam gear will now point straight down. Adjust all of the valves on the number four cylinder.

Rotate the crankshaft 180 degrees one more time, and adjust the valves on the number two cylinder.

Reinstall the valve cover using a new gasket and the original 10mm bolts. Bolt the timing cover back onto the engine and front of the valve cover. Start the engine and let idle. Test drive to verify the repair.

Items you will need

  • Socket set

  • Wrench set

  • Feeler gauge set

  • Small screwdriver

  • Valve cover gasket

 How to Adjust the Valves on a 1968 Ford 302

Remove the six bolts that secure the valve cover to the top of the cylinder head with a socket wrench and a socket extension. Three bolts are located at the upper edge of the cover, and three bolts are located on the bottom edge of the cover.

Lift the valve cover off the cylinder head to expose the rocker arms.

Start the engine.

Turn the nut in the center of any one rocker arm in a counterclockwise direction with a deep-set socket wrench until the rocker arm produces a tapping sound.

Turn the rocker arm's nut in a clockwise direction just until the tapping sound stops.

Turn the rocker arm's nut in a clockwise direction one-half of one turn in a clockwise direction to finalize the adjustment process.

Repeat the process for the remaining rocker arms on that cylinder head.

Turn the engine off.

Remove the gasket from the underside of the valve cover.

Apply engine assembly sealant to a new valve cover gasket.

Insert the gasket into the lip that surrounds the edge of the valve cover.

Lower the valve cover over the rocker arms.

Install and tighten the six bolts that secure the valve cover to the engine with a socket wrench and a socket extension.

Repeat steps 1 through 13 to adjust the valves under the other cylinder head.

Items you will need

  • Socket wrench

  • Socket extension

  • Deep-set socket wrench

  • Engine assembly sealant

  • Valve cover gaskets

 How to Adjust the Valves on a Ford 9N

Nonadjustable Lifters

Remove the tractor hood, fuel tank, hoses and any other parts necessary to access the engine. Drain the coolant from the engine block by placing a drain pan under the block and then opening the cock valve just behind the starter. Remove the intake and exhaust manifolds and remove the cylinder head. Also remove the side panel covering the valve train that is underneath the exhaust manifold.

Rotate the engine by hand so the No. 1 cylinder is at the top of its stroke. When on top dead center the exhaust and intake valve will both be completely closed. Locate the No. 1 corresponding valve train through the side panel on the engine block. Measure the distance between the valve stem and the solid lifter on the No. 1 cylinder with a feeler gauge. If the clearance exceeds 0.012 inch intake and 0.016 inch exhaust, remove the valve and either select a longer valve for reinstallation or reface the valve and valve seat to decrease the clearance. If the clearance is less than 0.010 inch intake or 0.014 inch exhaust, select a shorter valve or remove the valve assembly and grind the lower end of the valve stem until 0.010 to 0.012 inch intake and 0.014 to 0.016 inch exhaust are established.

Rotate the engine to the top dead center point for the No. 2 cylinder and repeat the process. Repeat until all valves have been set correctly. Reassemble the motor. Close the radiator valve, refill the radiator with coolant and check for leaks.

Adjustable Lifters

Shut off the fuel and unscrew the fuel line running to the carburetor. Disassemble the linkage between the governor and the carburetor. Remove the intake and exhaust manifolds from the engine. Remove the side panel that covers the valve train assemblies.

Rotate the engine until the No. 1 piston is on top dead center. Align the timing marks on the vibration pulley with the raised bar on the timing cover. When properly aligned, the intake and exhaust valve stems corresponding to the No. 1 cylinder will both be relaxed, and a feeler gauge can be inserted in either valve.

Measure the distances between the valve stems and lifter. Intake valves should fall between 0.010 and 0.012 inch. Exhaust valves should measure 0.014 to 0.016 inch.

Insert the valve lifter adjusting tool onto the intake lifter. The metal extension on the tool will engage the oiling slot on the exhaust lifter and hold both lifters in place so they won't rotate as the adjusting nut on the intake is rotated. Insert the feeler gauge between the intake valve stem and the intake lifter and rotate the adjusting nut so the feeler gauge can be pulled out with very little resistance. Tighten the adjusting nut and repeat the process for the exhaust valve.

Repeat the process by rotating the engine to the top dead center for each piston and measuring the corresponding valve lifters. When finished reassemble the engine.

Items you will need

  • Drain pan

  • Wrenches

  • SAE standard socket set

  • Valve lapping tools

  • Bench grinder

  • Valve lifter adjusting tool

  • Feeler gauge

 How to Adjust the Valves on a Ford Mustang 289

Remove the two valve covers with a socket wrench to access the rocker arms. Each valve cover is secured to the top of the cylinder head with six bolts. Remove the bolts with the socket wrench, and lift the valve covers off the cylinder head.

Turn the engine on and let it idle.

Loosen the adjusting nut on any one rocker arm with a socket wrench until an audible taping is heard. The adjusting nut is located in the center of the top of the rocker arm. Turn the adjusting nut in a counterclockwise direction to loosen it.

Tighten the rocker arm's adjusting nut by turning the nut in a clockwise direction with the socket wrench just until the tapping sound stops.

Turn the rocker arm's adjusting nut an additional 1/4 turn with the socket wrench to complete the adjustment process for that rocker arm.

Repeat Steps 1 through 5 for the remaining 15 rocker arms while allowing the engine to idle.

Turn the engine off.

Apply engine sealing compound to a pair of new valve cover gaskets, then position the gaskets onto their respective valve covers.

Lower the valve covers onto the cylinder heads, then tighten each cover's six retaining bolts with a socket wrench.

Items you will need

  • Socket wrench

  • Engine sealing compound

  • Valve cover gaskets

 How to Adjust Valves on a GM 350 Engine

Start the engine and allow it to reach normal operating temperature.

Remove both of the valve covers. A single valve cover is located on either side of the intake manifold. Each valve cover is attached to its cylinder head with a total of four bolts. Two of the bolts are located on the top of the cover, while the remaining two are on the bottom. Remove the four bolts with a wrench, then lift the valve cover off the cylinder head.

Identify each rocker arm's adjusting nut. The 350 engine uses a total of 16 rocker arms. In the center of each rocker arm is a single nut. It is this nut that is either tightened or loosened to adjust its corresponding valve. Also note that the tip of each rocker arm rests on top of a metal rod, called a pushrod.

Start the engine and allow it to idle. Loosen the single nut in the center of one rocker arm with a wrench until a clattering sound is heard, then tighten the nut just until the clattering stops. Turn the adjustment nut in a clockwise direction one full turn with the wrench to complete the adjustment for that valve. Repeat the processes for the remaining 15 valves, then turn the engine off.

Install the valve covers. Each of the two valve covers use a single gasket to prevent oil from leaking onto the engine. These gaskets are not reusable, and must therefore be replaced. Peel the old gasket off of the valve cover, then apply a single bead of gasket sealer onto one side of a replacement gasket. Place the coated side against the inner lip of the valve cover, then apply a single bead of gasket sealer onto the opposite side of the gasket. Place the valve cover onto the cylinder head, then install and tighten each of the cover's four retaining bolts. Repeat the process for the remaining valve cover.

Items you will need

  • Wrench

  • Valve cover gaskets

  • Gasket sealer

 How to Adjust the Valves on My Triumph Spitfire

Apply the parking brake, shift the car into neutral and chock the wheels.

Remove the spark plugs, valve cover and valve cover gasket.

Number the rocker arms and valves from #1 to #8, starting at the front of the engine.

Rotate the engine with a 1 13/16-inch socket and 3/4-inch breaker bar until the #1 valve is fully open and just starting to close. Adjust the #8 valve to .010 clearance with a 1/2-inch wrench and screwdriver.

Rotate the engine with the 1 13/16-inch socket and 3/4-inch breaker bar until the #2 valve is fully open and just starting to close. Adjust the #7 valve to .010 clearance.

Adjust the valves from front to rear using the "rule of nines." The "rule of nines" is: 9 - (# of the valve fully compressed) = the # of the valve to adjust. For example, when valve #3 is in position, it is time to adjust valve #6 (9 - 3 = 6).

Repeat Step 6 until all valves have been adjusted. Replace the spark plugs, valve cover and valve cover gasket.

Items you will need

  • Wheel chocks

  • Metric socket set

  • 1 13/16-inch socket

  • 3/4-inch breaker bar

  • 1/2-inch combination wrench

  • Flat head screwdriver

  • Valve cover gasket