Mercury F4AZ-6571-A Seal - Valve Stem

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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.

Damage to the valve springs and worn value stem seals can be done without removing the cylinder heads by two techniques. The manufacturer-recommended method allows for the removal of the valve springs and seals without taking out the camshafts, requiring two special tools: a valve spring spacer: T91P-6565-AH, and a valve spring compressor: T91P-6565-A which are manufactured especially for overhead cam engines. With the help of the camshaft, the compressor pushes down over the spring freeing the tension exerted on the cam follower and to prevent the spring from over compressing which may result in the damage of the valve stem seal there is the spacer. The second technique needs the withdrawal of the camshaft and even though it can yield good results, it uses a more readily accessible probe. In either case a compressed air source is often required or a piece of nylon line can be left in the cylinder to stop the valves falling in. Anything that involves taking off the valve cover, or removing the spark plugs or the crank to set the piston at the top of its compressional cycle at Top Dead Center is, in fact, a process of removal. Whenever machining a cylinder barrel, the air hose adapter which is threaded into the spark plug hole is used to hold the valves by application of compressed air. In the absence of compressed air, a long nylon rope may be inserted into the combustion chamber. One of the miracles of motor vehicles should be to stuff the shop rags into the cylinder head holes so that the parts do not fall in. The three hole spacer and the valve spring compressor are used in order to remove the camshaft roller follower, keepers, spring retainer and finally the valve spring. The valve stem seal is then pulled out and if air pressure do not retain the valve closed then additional repair work may be required. The camshaft and roller followers are then un- screwed out; then the valve spring compressor is fitted. When the spring has been compressed, the keepers, spring retainer, and valve spring are taken out; at the same time the stem seal is removed. During installation there is usually a rubber band or tape winding round the valve stem so that it cannot fall after sometime and to retain the valve in its closed position air pressure is red applied. The valve stem is lubricated and a new seal is put in place after which the spring and a retainer are put in place. Some of the keepers are located in the groove and the pressure on the spring tool is reduced so that it can snap back to make contact with the keepers. Last of all, the air hose connection is removed and the adapter is withdrawn, and if ever the camshaft was retrieved, it is then reinserted. Spark plugs are then replaced and the rest of the procedures are reverse of the removal process, the engine is then cranked and checked for oil leakages and unusual noises.

The valvesprings may become broken and the valve stem seals may be worn out and can be replaced while the cylinder heads remain in the engine, it only needs two special tools and a Air Compressor. However, if compressed air is unavailable, then it is possible to tie the valves with a nylon rope so that they do not drop into the cylinder. Starting this step by disconnecting the valve cover of the cylinder head or head or heads and in case all the valve stem seals are being to be renewed, both the covers must be removed. After this, remove spark plug from the cylinder which is affected, and if all seals are to be replaced, make certain that all the plugs have been removed. Slightly turn over the crankshaft to bring the piston in the cylinder in question to the TDC position on the compression stroke, and proceed through the firing order commencing with No 1 cylinder. A thread an adapter into the spark plug hole, then attached an air hose to a compressed air supply. The bolt, fulcrum, and rocker arm for the defective valve should be taken out and so also should be the pushrod. Attach compressed air to the cylinder in which the valves are supposed to be arrested; otherwise, the valves may be arrested by placing the piston about forty-five degrees before TDC and inserting nylon rope through the combustion chamber. Clean parts with shop rags so that they do not fall into the engine, and to compress the valve spring you require a valve spring compressor to remove the keepers. Should air pressure not be enough to keep the valve shut, the valve face or seat may get damaged, to be dealt with by having to get the cylinder head off. Then you need to immobilize the valve stem for instance by wrapping it with a rubber band or the tape before deflating the tire. Check up the stem of the valve for any sign of wear and ensure that it slides effortlessly in its guide. Use compressed air to maintain the valve shut, grease the valve stem, and fit a new guide washer. Place the spring over the valve, put in the retainer, compress the spring, and place the keepers and apply grease to prevent slipping of the keepers. Take off the pressure from the spring tool then, release the air hose then, take off the adapter. Last, place back the rocker arms and pushrods along with the spark plugs and the valve covers, start the car to inspect any oil leaks or abnormal sounds.

Valve Springs and valve stem seals are fairly simple therefore damaged ones can be changed without having to bare the cylinder heads and it usually require only two special tools and compressed air source. Start by taking off the valve cover of the cylinder head you suspect to have problems, although if all valve stem seals will be replaced, both covers should be removed. Subsequently, extract one of the spark plugs from the one cylinder with the damaged component and if replacing all the seals, to and remove all of the spark plugs. Adjust the crankshaft until the piston of the cylinder that has been identified to have the issue is positioned at the Top Dead Center at the compression stroke and should begin with cylinder number one and then follow the firing sequence. Insert an adapter into the spark plug hole together put an air hose connected to a compressed air. Depower the valve with the bad section and pull out the pushrod and the associated bolt, fulcrum, and rocker arm. Use compressed air to the cylinder and both valves should remain fixed on the cylinder. Work a rag into the cylinder head holes to keep parts from falling into the engine; to remove the keepers use a valve spring compressor and pull the spring to allow you to remove the keepers with needle nose pliers or magnet. In the event that the air pressure will not close the valve, there is possibility that the face or seat of the valve will be harmed or damaged, where the additional process of pulling the cylinder head will take place. Put a rubber band or tape around the head of the valve stem to ensure that the valve doesn't fall into the combustion chamber, then deflate it. Check the valve stem for sign of wear, it must rotate smoothly and the binding should not be present. Apply pressure on the valve again so they remain closed, finally remove the tape or rubber band that was used. Remove the old rubber guide seal wash the grease from the stem and lubricate it and install a new guide seal in addition to the spring and retainer. Compress the cover of the valve spring and place the keepers in the groove, and put a little grease to prevent the Keepers from falling. Take off the spring tool pressure and the keepers should seat themselves, after which the air hose and the adapter should be disconnected. The rocker arm(s) should be reinstalled, then the push rod(s), spark plug(s) and wire(s) should then be put back on and closed off with the valve cover(s). Open the hood and turn ignitions and examine for signs of oil seepage and any funny noises originating from the top of the engine.

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.

Thread an adapter into the spark plug hole and connect an air hose from a compressed air source to it. Apply compressed air to the cylinder.

Remove the spark plug from the cylinder with the defective component. If all of the valve stem seals are being replaced, remove all the spark plugs.

Yes, there is a method using a tool recommended by the manufacturer that allows for the removal of the valve springs and seals without removing the camshafts.