Nissan 13207-2B500 Seal Valve

To replace failed valve springs and leaking valve seals without cylinder head removal, carry out the following steps meticulously. Start with removing the upper and lower intake plenum, as well as the valve covers, then move ahead to timing chain, camshafts and lifters from both cylinder heads disassembly. Remove spark plugs and turn the crankshaft until piston on affected cylinder reaches top dead center (TDC) on compression stroke doing one cylinder at a time in firing order sequence. Screw a long adapter into spark plug hole, connect an air hose from compressed air source to pressurize the cylinder. To prevent losing parts inside engine place shop rags in holes of the cylinder head around valves and then use valve spring compressor to compress spring freeing valve stem keepers. Take out keepers; check for damage on a valve stem and if it binds. Reapply air pressure to hold the valve closed, release any temporary restraints, lubricate oil engine into valve stems and using a special tool or deep socket with hammer install new seals of the stem for valves. Install valve spring, retainer and keepers ensuring that they are correctly positioned then remove compressor spring. Remove this hosepipe then fix back spark plug adapter after which you will finally proceed to putting camshaft lifters timing chain covers other than going down through spark plugs ignition coils upper lower intake plenum. Eventually begin engine running checking for oil leaks and any abnormal sounds from the vicinity of cover over valve areas.

Broken valve springs and defective valve stem seals can be replaced without removing the cylinder heads, typically requiring two special tools and a compressed air source. Begin by removing the valve cover(s) and the rocker arm assembly, followed by the lifter assembly. Remove the spark plug from the affected cylinder, or all if replacing all valve stem seals. Turn the crankshaft until the piston in the affected cylinder is at Top Dead Center on the compression stroke, starting with cylinder number one and working through the firing order. Thread a long adapter into the spark plug hole and connect an air hose from a compressed air source. Apply compressed air to the cylinder, taking care as the piston may be forced down, potentially causing the crankshaft to turn suddenly. Stuff shop rags into the cylinder head holes around the valves to prevent parts from falling into the engine, then use a valve spring compressor to compress the spring and remove the valve stem locks. Inspect the valve stem for damage, ensuring it doesn't bind in the guide. Reapply air pressure to retain the valve in the closed position, lubricate the valve stem with engine oil, and install a new valve stem seal, ensuring intake and exhaust seals are not mixed. Install the inner and outer springs over the valve, followed by the valve spring retainer, compressing the springs to position the valve stem locks. Remove pressure from the spring tool, disconnect the air hose, and remove the adapter. Reinstall the lifter assembly and rocker arm assembly, followed by the valve cover and spark plug(s). Start the engine and check for oil leaks and unusual sounds from the valve cover area.

If you want to replace damaged or worn out valve stem seals as well as broken valve springs without removing the cylinder heads,Begin by taking off the rocker arm assembly then the valve cover (s), and finally, you can remove the lifter guide assembly. Unscrew the spark plug from the affected cylinder (or all spark plugs if replacing all valve stem seals) and make sure the piston in that cylinder is at Top Dead Center on compression stroke moving through firing order sequence where necessary. Screw a long adapter into the spark plug hole and connect it to compressed air source. Introduce compressed air into the cylinder as well as place shop rags around each of the valves to prevent debris from falling into engine. Use pliers or magnet to remove them after releasing the valve keepers and compressing spring with a valve spring compressor. Ensure valves are kept in place using air pressure because poor face or seat conditions may cause air leaks. Take off the shield, spring retainer, valve spring and finally, remove the valve stem seal. Before releasing air pressure, secure its valve stem by using a rubber band or tape so that it will not slip down into combustion chamber. In case of binding between guide and stem, head should be removed for repair since it indicates either a damaged guide or valve which is extremely bad news when things like this happen inside an engine in motion. Reapply pressure again which would hold close both exhaust and intake valves, while taping is released along with booting of oils on new stems of valves before installing new ones too into guides meant for each cylinder's own sets of valves also being pushed down according to acceptable depth by tapping such until they become fully seated with their respective shoulders against top surface of cylinder head. The tool used for this purpose can be a socket extended deep inside of engine upon applying light blows with a hammer so that it fits up tightly just within limits allowed by configurations drawn up by manufacturers for an intake valve seal. Place exhaust seals in as far as just internal fingers will allow as soon as you see them ready to go home to the bottom of their respective counterbores. Be careful enough not to mix up intake and exhaust seals. Install the inner and outer springs with closely-wound coils against the cylinder head, then put the valve spring retainer on and finally, hold keepers in groove gently applying some grease to help keep them in place temporarily at least until pressure is off from such a tool of theirs for retention purposes. Remove pressure from the spring tool and ensure that keepers have been seated correctly. Disconnect air hose and adapter, install lifters assembly, rocker arm assembly, valve cover(s), spark plug(s) and wires. Start engine; check oil leaks as well as unusual sounds coming from valve cover area.