Ford F77Z-6571-AB Valve Stem Seal

Exhaust and intake valve springs may be replaced with the cylinder heads in the car, though they may need to be removed if the seats or seals on the stems have worn; replacement of these usually requires two specialized tools and compressed air. In case compressed air is not available, a piece of nylon rope can be employed such as to keep the valves from falling inside the cylinder. First, take off the valve cover of the cylinder head, which unfortunately need to be changed, and if all the valve stem seals are being replaced, the two covers. The next step is to remove the spark plug which will be located within the cylinder containing the faulty part ; if changing all seals this will require the removal of all spark plugs. Rotary the crankshaft in such a manner that the piston in the required cylinder is on the TDC of the compression stroke starting with cylinder no 1 and then following the firing sequence. Place the adapter to the spark plug hole, then attach the other end of the air hose to the compressed air. It is recommended that rocker assembly of the failed side be pulled off and, if replacing all the seals, remove both of them. To do this, the compressor should be connected to the cylinder, the valves should be secured in place in the cylinder. Have to use shop rags to block such holes on the cylinder head so that none of the parts drops inside the engine. Loosen the machine by rotating a valve spring adjuster and squeezing the valve spring by a valve spring compressor. After you have had your spring retainer and your valve spring removed, you also have to remove the valve stem seal. If the pressure of air does not shut the valve then the face or the seat of the valve is likely to be chafed, requiring the cylinder head to be pulled for repairs. Place the tip of the valve stem in the slot and wind a rubber band or some tape around the stem head to avoid it falling into the combustion chamber, then discharge the pressure. Check the valve stem for damage and the movement should be smooth without having to force the stem within the guide. Apply air pressure to maintain the closure of the valve and then, remove the tape or rubber or any such band. Cover the valve stem with engine oil and then put a new stem seal by using the seal installer tool. Align the spring over the valve; fit the valve spring retainer; compress the spring and the valve stem locks are put in while a drop of grease is used to hold the locks firmly. Release the pressure from the spring tool and make sure that the lock are properly positioned. Remove the air hose and take off the adapter from the spark plug hole and put in the rocker arm assembly, the spark plug or plugs with the wire, or wires and valve covers as appropriate. Last but not the least, turn on the ignition and look for the signs of oil dripping down on areas aside the valve cover and any strange sounds emanating from the areas.

Valve spring control and figure 'D' of the valve stem seal can be held from the lateral, with some minor portions demanding only two special tools and a compressed air resource, without requiring cylinder head extraction. Start by removing the valve cover from the cylinder head or heads and, if all of the valve stem seals are being changed, both covers. Subsequently, set back the spark plug of the particular cylinder in question, and, if want remove all the spark plugs. Rotate the crankshaft in such as manner that the piston in the concerned cylinder is at the topmost position of stroke sequence on the compression stroke and the firing order is one, two, three and four. Insert an adapter into the spark plug opening and attach an airline to a source of air pressure. Unlock the bolt of the valve and the fulcrum and rocker arm of the defective part, next withdraw the push rod. Put the compressed air to the cylinder so that the valves are secured in position because of the air pressure. Climb up and stuff shop rags into any holes in the cylinder head to stop parts from falling into the engine; now you will need a valve spring compressor to compress the spring and remove the locks on the valve stem. Then, with the spring retainer and valve spring assembly out, pop out the valve guide seal. If either the face or the seat does not seal adequately to help keep the valve shut, then face or seat requires cylinder head pull for repair. Using the assistance of a rubber band or narrow tape cover the distal end of the valve stem so that it cannot go into the combustion chamber and then release the pressure. Check the condition of the valve stem as well as its movement around the guide-it should not be tight. Apply air pressure to close the valve, and then remove the tape or rubber band that was used to stop air pressure. A new guide seal should be fitted and the valve stem lubricated before the spring and the valve spring retainer. Just as with the spring the on the engine side of the head, compress the upper valve spring and insert the valve stem locks with a small drop of grease on them. Take off the pressure from the spring tool and allow the locks to settle into place. Remove the air hose and the adapter from the spark plug hole-reinstall the rocker arm and push rod then the spark plugs along with the spark plugs wires if any. Last of all fit the valve cover(s) turn on the engine and check for any signs of oil leakage and noises emanating from the valve cover gasket area.

The valve springs can break over time and the valve stem seals can become defective; in either case, the individual components can be swapped without having to remove the cylinder heads due to a second method recommended by the manufacturer which also does not require removing the camshaft although a special tool exclusive to the SOHC engine is used. It is a valve spring compressor that just uses the camshaft as the fulcrum and with the aid of a ratchet to compress the spring and take off tension on the valve stem locks. The second procedure requires the utilization of a more familiar tool, but the valve springs are designed in such a way that they are recessed, and as a consequence, most clamp-type spring compressors cannot be employed unless the cylinder head is detached. When the cylinder head is pulled off, a normal C-clamp-type compressor is used on the spring pockets with an extension. For this operation, a compressed air source is sometimes required, therefore it is recommended to assemble the required tools in advance. The procedure starts with the dismantling of the valve cover and spark plug from the chosen cylinder and placing the piston on the top dead centre on the compression stroke. There is a thread air hose adapter inserted into the spark plug hole so that with the help of compressed air valve is held. Shop rags must be packed into the cylinder head holes to avoid that some parts may fall into the engine. The spring is then pushed to take out the rocker arm and every component is labelled for ease of reassembling. With the spring compressed, the lock of the valve stem is un-fastened and the spring retainer, the valve spring and finally the valve stem seal. If air pressure cannot retain the valve closed further checks on the valve face and seat are required and in some cases cylinder heads may have to be removed for further valve repairs. The valve stem is tied with a rubber band or a tape after which, the valve is checked for damage, lubricated and a new seal is fitted. The spring and retainer are then placed and the stem lock of the valve is greased if required. When the lock is properly positioned, the air hose is disconnected and the rest of the installation performed in the same manner as the removal. Last of all, the engine is started again and the bonnet is kept open in order to observe whether there is any oil leakage and also to listen to any unusual sound that may be produced by the engine.

Stuff shop rags into the cylinder head holes above and below the valves.

If air pressure fails to hold the valve in the closed position, the valve face or seat is probably damaged, and the cylinder head will have to be removed for additional repair operations.