Ford AA5Z-6507-A Inlet Valve

The engine must be cold as the checking of the valve clearances should be done only in case where camshaft or other parts related to the valve have been changed or replaced or where excessive noise is heard coming from the valve train area. Loosen the connection of the cable from the negative terminal of the battery, next remove the spark plugs and the valve covers. Loosening the crankshaft pulley centre bolt one can use a socket and a breaker bar to rotate the engine until the camshaft lobes of the cylinder to be checked are positioned away from the tappets. With the feeler gauge, ascertain valve clearance for the valves which have been indicated and ensure they jot down all the readings taken; then compare the observed readings with the standard valve clearance in order to point out those valve clearances which are beyond the standard. Do the same process to all valves to obtain its initial measurement. If any clearance is out of specification, one has to replace the tappet with one of another thickness to correct it and, of course, the camshafts have to be removed in order to be able to deal with the tappets. Sticker the lifters for replacement and the valves that should go together with them using a micrometer to measure the thickness of the head of each lifter to the nearest 0.001 inches. If you'd like to know how thick the new lifter should be so as to achieve the desired valve clearance, then the formula N equal R + (M1-M2) should do it for you, where N is the thickness of the new tappet, R is the thickness of the old tappet, M1 is your measured valve clearance and M2 is the standard valve clearance. Coated lifters are coded on the bottom aspect to express their measurement where a marking of 3.310 denoted thickness of 3.31 mm or 0.13 inch. At last, select the new lifters that should be placed in the specific location, while apply the engine assembly lube on it, and place it into its correct position; replace the camshafts and timing chains back, and check it with the valve clearance.

Disconnect the cable from the negative terminal of the battery, then remove the spark plugs and the valve covers. Using a socket and a breaker bar on the crankshaft pulley center bolt, rotate the engine until the cam lobes on the cylinder to be checked are pointing away from the lifters. Measure the clearance of the valves with a feeler gauge, ensuring that the gauge has the specified thickness; if the clearance is correct, a slight drag should be felt when pulling it out. Record each measurement and compare them with the desired valve clearance found in the specifications, noting any that are out of specification for later reference regarding required replacement lifters. Repeat the measurement process until all valve clearances have been assessed. If any clearance is out of specification, replace the lifter with a new one that has a different thickness head to correct the clearance, which requires removing the camshafts to access the lifters. Mark the lifters to be replaced and record their corresponding valves, using a micrometer to measure the thickness of the head of each lifter precisely at the center projection on the underside. To calculate the correct thickness for a replacement lifter that will achieve the specified valve clearance, use the formula: N equal R + (M1 - M2), where N is the thickness of the new lifter, R is the thickness of the old lifter, M1 is the measured valve clearance, and M2 is the standard valve clearance. Lifters are marked on the underside to indicate their size; for example, a marking of 3.310 indicates a thickness of 3.31 mm or 0.13 inch. Finally, mark the new lifters for their destination, lubricate them with engine assembly lube, and install them. After replacing the lifters, reinstall the camshafts and timing chains, then re-check the valve clearances.