Ford AT4Z-6505-A Exhaust Valve

It is important to check the valve clearances with the help of a cold engine. It is recommended that the valve clearances be checked and altered only after the camshaft(s) or any other related valve parts have been replaced, or when there is much rumbling noise in the valve-train. Start from disconnecting the cable that is connected to the negative terminal of the battery next is remove the spark plugs and the valve covers. Position the engine with the crankshaft pulley center bolt on the cylinder to be checked until cam lobes are out of the lifters as possible using socket and breaker bar. Gauge the clearance of each valve with a feeler gauge of the specified thickness; slight drag on the feeler gauge will tell that the clearance is correct. Record any valve which is out of specification as this will form part of the analysis when estimating the number of required replacement lifters. Again we shall repeat the same process for all the valves. Any of the clearance that exist must be adjusted by replacing the lifter with a new lifter whose thickness head is of a different measure. Stoke the lifters to be replaced and record their assorted valves. Head thickness of each lifter is to be measured using the micrometer on the center projection on the underside for accuracy. To calculate the correct thickness for a replacement lifter that will achieve the specified valve clearance, use the formula: A new lifter thickness would therefore be calculated as: N equal R + (M1-M2) These lifters are stamped on the bottom to show their size such a code 3.310 means the thickness is 3.31mm or 0.13 inch. This lifters are then marked according to their installation location, then applied with engine assembly lube and finally installed. To rectify the problem replace the lifters, reset the camshafts and timing chains and after that adjust the valve clearances.

Disconnect the cable from the negative battery terminal. Remove the spark plugs, then take off the valve cover. Loosen the right front wheel lug nuts, raise the front of the vehicle, and support it securely on jackstands before removing the wheel. Remove the fender splash shield. Using a wrench or socket on the crankshaft pulley bolt, rotate the crankshaft clockwise and check each lifter when its camshaft lobe is straight up, ensuring that the measurement is between the base circle of the camshaft lobe and the top of the lifter. Use feeler gauges to measure the clearances, ensuring a slight drag is felt as the feeler gauge is slid between the lifter and the camshaft. The clearance must be checked between each camshaft lobe and the lifter it operates, and careful notes of the measurements recorded for each lifter should be kept. If some measurements fall outside the recommended clearances, the camshafts must be removed, and the out-of-spec lifters replaced. New lifters are available with various thicknesses to correct the valve clearances, each marked with a thickness number. To determine the desired thickness for new lifters, add the thickness of the original lifter to the measured clearance, then subtract the mid-range figure for ideal clearance to find the proper lifter thickness to order, keeping in mind that not every thickness is available. Install the camshafts, then recheck the valve clearances. The remainder of the installation is the reverse of removal; run the engine and check for oil leaks.

The remainder of installation is the reverse of removal. Run the engine and check for oil leaks.

Checking and adjusting the valve clearance is only necessary after the replacement of the camshaft(s) or other valve-related parts, or if the valve train is making excessive noise.

Disconnect the battery cable from the negative battery terminal.

Using a wrench or socket on the crankshaft pulley bolt, rotate the crankshaft clockwise and check each lifter when its camshaft lobe is straight up. Ensure that the measurement is between the base circle of the camshaft lobe and the top of the lifter. Use feeler gauges to measure the clearances. If the clearance is correct, you should feel a slight drag as the feeler gauge is slid between the lifter and the camshaft.