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.