Mercury E7ZZ-6571-A Valve Stem Seal

To replace broken valve springs or defective valve stem seals without removing the cylinder heads, specific tools and compressed air are needed. Remove valve cover(s) and spark plug(s) from affected cylinder. Ensure piston is at Top Dead Center on compression stroke. Thread adapter into spark plug hole and connect air hose from compressed air source. If no air pressure, insert nylon rope into combustion chamber to prevent valve drop. Remove rocker arm, fulcrum, and pushrod for affected valve. Apply compressed air to hold valves in place. Alternatively, with rope, stuff rags into cylinder head holes, use valve spring compressor to compress spring, remove keepers, and disassemble valve components. Inspect valve stem for damage, lubricate it, and install new valve guide seal. Reassemble valve components, release air pressure or rotate crankshaft, and reinstall rocker arm(s), pushrod(s), spark plug(s), and valve cover(s). Start and run engine, check for oil leaks and unusual sounds from valve cover area.

Valve springs and valve stem seals can be replaced without removal of cylinder head; normally it requires two special tools and compressed air. If there is no compressed air the valves can be secured in place using a length of nylon rope to stop them falling into the cylinder. Start with the removal of the camshaft cover, spark plug from Cylinder head with defective component or all spark plugs where replacing all valve stem seals. Rotate the crankshaft until the piston in the affected cylinder is at the TDC of the compression stroke and if doing all the seals, start with cylinder number one and do in the firing order sequence. Take an adapter and insert it into the spark plug fitting that is frequently used in connection with your air hose, and use the compressed air in order to secure the valves. In case of lack of air pressure, place the piston as near to top dead centre as possible on the compression stroke and push into the combustion chamber a nylon rope with its end left exposed for withdrawal. Plug up the cylinder head holes with shop rags so that no contaminants can get into the engine, then, use a valve spring compressor to compress the spring. After compressing the spring, take out the cam follower and the lash adjuster, the keepers, the spring retainer, the damper assembly and the valve spring. Remove the valve stem seal and if air pressure cannot retain the valve closed, you may be looking at a hassle with the valve face or seat that would require removal of the cylinder heads to have it fixed. Put a piece of a rubber band or an adhesive tape around the valve stem with the intention of preventing it from falling off.Now, allow the pressure to fade and give the valve stem a good check to ensure it rotates in the guide as required. Reverse the valve to keep it shut by applying air pressure, apply engine oil the valve stem and fit a new umbrella type guide seal. Put the installation cap on the stem of the valve, fit the valve stem seal over the cap and screw down till the seal is in contact with the guide. Take off the cap and insert, with a special installation tool or screwdrivers, the seal to the valve guide. It fits the valve spring, damper and retainer; compress the spring then fit the keepers; lash adjuster to be fitted along with cam follower. Release from the spark plug hole the air hose and the adapter if used or pull out the used rope as well. Last, replace the parts that were unbolted, turn on the engine, and look for possible signs like dripping oil or foreign noises emanating from the region of the camshaft cover.

Broken valve springs and defective valve stem seals can be replaced without removing the cylinder head, typically requiring two special tools and a compressed air source. If compressed air isn't available, a length of nylon rope can be used to prevent the valves from falling into the cylinder. Begin by removing the rocker arm cover and the spark plug from the affected cylinder, ensuring to remove all spark plugs if replacing all valve stem seals. Turn the crankshaft until the piston is at top dead center on the compression stroke, and if replacing all seals, start with cylinder number one, following the firing order. Thread an adapter into the spark plug hole and connect an air hose from a compressed air source. Loosen the rocker arm shaft support bolts to relieve valve spring tension, slide the rocker arms aside, and remove the pushrods. Apply compressed air to hold the valves in place; if there are leaks, an alternative method involves positioning the piston just before TDC and feeding nylon rope into the combustion chamber. Use shop rags to prevent debris from entering the engine, then compress the valve spring with a valve spring compressor and remove the keepers. If air pressure fails to hold the valve closed, the valve face or seat may be damaged, necessitating cylinder head removal for repairs. Wrap a rubber band or tape around the valve stem to prevent it from falling, then release the air pressure. Inspect the valve stem for damage and ensure it moves freely in the guide. Reapply air pressure to retain the valve, lubricate the valve stem with engine oil, and install a new seal, spring, and retainer. Compress the spring and position the keepers, applying grease to hold them in place. Remove pressure from the spring tool, disconnect the air hose, and reinstall the rocker arm assembly and pushrods, followed by the spark plug(s) and wire(s). Finally, install the rocker arm cover, start the engine, and check for oil leaks and unusual sounds.

Start and run the engine, then check for oil leaks and unusual sounds coming from the valve cover area.

The intake valve seals are identified by the marking "IN".

The valve spring compressor, utilizing the camshaft as a pivot point, applies pressure to release tension on the cam follower, while the spring spacer prevents over-compression.

After reassembling the valve components, the air pressure should be released or the crankshaft should be rotated.

Position the piston approximately 45-degrees before TDC on the compression stroke, then feed a long piece of nylon rope through the spark plug hole until it fills the combustion chamber. Rotate the crankshaft until slight resistance is felt.

Wrap a rubber band or tape around the top of the valve stem, then release the air pressure. If a rope was used instead of air pressure, turn the crankshaft slightly in the direction opposite normal rotation.

The valve face or seat is probably damaged, and the cylinder head will have to be removed for additional repair operations.

Specific tools and a compressed air source are needed.

Remove the valve cover from the affected cylinder head. If all of the valve stem seals are being replaced, remove both valve covers.