Ford AT4Z-6256-B Camshaft Sprocket

These engines some how are not easily serviceable and usually they need special tools. Any procedure that requires getting close to the timing chains should be done with caution, and any disassembly must be done with the special tools; otherwise, an engine is doomed. Again, since this is an interference engine design, if the timing chain has broken, there is bound to be valve and possibly piston damage and this will mean that the cylinder heads have to be pulled. Timing is especially tricky, and errors will lead to serious damage to the engine, for instance. Do not perform this procedure unless very comfortable with this type of repair; if in any doubt seek advice from a specialist. Check all work and be absolutely sure that all is correct before trying to switch on the engine. On 2010 and earlier engines, this procedure must be carried out with the engine removed and a pair of narrow-headed camshaft holding tools are needed. On 3.5L and 3.7L engines, the water pump Is located behind the timing chain, and it is convenient to replace the water pump during the timing chain replacement. First, you keep off the negative terminal of the battery, then the valve covers along with the timing chain cover. As for the 2.7L models, replace the old crankshaft pulley bolt, rotate the engine to the direction of the keyway on the crankshaft being in the 11 o'clock position, and be certain that the triangle timing marks on VCT units. Take off the right side tensioner and guide, take the timing chain off the VCT units, and turn over pulley bolt. The same should be done to the left-side chain with the same specification of the alignment of the timing marks. For removing the VCT unit engage the special tool over the camshafts to pull the locking tabs the center bolts of VCT unit and then slide off the VCT unit from the camshafts. Finally for 2010 and earlier 3.5L and 3.7L models replace the crankshaft sprocket bolt, align the engine TDC for the cylinder number 1, and fit the special holding tools for the camshaft. The following should be done: VCT assembly mounting bolts, primary timing chain tensioner and chain should be taken out. For the models produced after the year 2011, make the engine clockwise rotate until the VCT units align themselves to 90 degrees of camshaft position and then remove the tubes of valve train oil and install the two special camshaft locking tools. Take out the principal timing chain and the second timing chains, if they are required. For installation make sure the timing marks are aligned, install new VCT unit center bolts and tighten to the specified torque value. Insert all the other parts in reverse manner, then turn the crankshaft by your hand at least two full turns and check whether there is any do not apply resistance. Last is to fit a new oil filter, replace engine oil and coolant and start the engine let it to warm up to examine any leakage.

Pull the timing chain cover and take the crankshaft position sensor trigger wheel off the crankshaft thus observing the position of the slot and the key way on the trigger wheel so that the pulse wheel may go in the correct position. Take out spark plugs because these engines have two timing chains; one is ahead, which operates camshaft sprocket on the rear cylinder head and the other is the one closest to the block and controls the camshafts for the front cylinder head. Bolt in the crankshaft pulley retaining bolt and rotate the crankshaft clockwise till the key way is aligned at the 11 O'clock position & TDC marks noted on the camshaft sprockets are lined. If not aligned turn the crankshaft one full turn and then check it again. Check the marks on the sprockets and mark the chain links if required and turn the Crankshaft to the 3 o'clock position to align the rear Camshaft sprockets in their non-operational position distancing the valves from the pistons. As for the VCT assembly, you should unbolt the mounting bolts of the assembly as well as the bolts of the timing chain tensioner of the rear chain after which, you should take out the rear timing chain from the cam sprockets. The crankshaft bolt, the chain guide/VCT assembly bolts and open the rear timing chain sprocket and take it off. Turn the crankshaft 600 degrees anticlockwise to position the front camshafts at top dead center, then loosen the front timing chain tensioner bolt and raise the front timing chain off the sprockets. If required, remove the front timing chain crankshaft sprocket from the crankshaft end. For the 3.5L engine the timing chain cover should be removed, the crankshaft sprocket bolt is fitted with the engine at TDC for cylinder No. 1. Screw in special camshaft holding tools to hold the camshafts at TDC, then remove the VCT assembly mounting screws and the primary timing chain tensioner. Scribe the chain links opposite the timing marks and then take out the primary timing chain and then the upper chain guide. If secondary timing chains and camshaft sprockets are to be removed, turn the tensioners to the left compressing them and inserting a pin to retain in position. Take the bolts of intake and exhaust camshaft sprockets but make sure that the camshaft holding tool is fitted. For 2013 and later models place the engine clockwise so that the VCT units lie parallel to the cylinder heads and then remove the valve train oil tubes and lock the camshaft with the special tools. If timing marks are concealed, painting of dots is done on the object in question as a guide during alignment. Take out the timing chain tensioner and the lower chain guides, and also the bolts fastening the VCT solenoids. Wash all components of the engine and check accidentally wounded or used components before reestablishment of the engine. Before installing the timing chain ensure the timing chain tensioners are fully compressed and locked for easy installation of the chain whereby, coloured links match index marks on the sprockets. Any of the colored links should align with index marks and tighten the timing chain guides and tensioners. Crank the engine in the normal fashion at least two full turns the look for binding and then add more oil and coolant to the crank case reconnect the battery to the starter and start the engine to look for any leakage.

These engines some how are not easily serviceable and usually they need special tools. Any procedure that requires getting close to the timing chains should be done with caution, and any disassembly must be done with the special tools; otherwise, an engine is doomed. Again, since this is an interference engine design, if the timing chain has broken, there is bound to be valve and possibly piston damage and this will mean that the cylinder heads have to be pulled. Timing is especially tricky, and errors will lead to serious damage to the engine, for instance. Do not perform this procedure unless very comfortable with this type of repair; if in any doubt seek advice from a specialist. Check all work and be absolutely sure that all is correct before trying to switch on the engine. On 2010 and earlier engines, this procedure must be carried out with the engine removed and a pair of narrow-headed camshaft holding tools are needed. On 3.5L and 3.7L engines, the water pump Is located behind the timing chain, and it is convenient to replace the water pump during the timing chain replacement. First, you keep off the negative terminal of the battery, then the valve covers along with the timing chain cover. As for the 2.7L models, replace the old crankshaft pulley bolt, rotate the engine to the direction of the keyway on the crankshaft being in the 11 o'clock position, and be certain that the triangle timing marks on VCT units. Take off the right side tensioner and guide, take the timing chain off the VCT units, and turn over pulley bolt. The same should be done to the left-side chain with the same specification of the alignment of the timing marks. For removing the VCT unit engage the special tool over the camshafts to pull the locking tabs the center bolts of VCT unit and then slide off the VCT unit from the camshafts. Finally for 2010 and earlier 3.5L and 3.7L models replace the crankshaft sprocket bolt, align the engine TDC for the cylinder number 1, and fit the special holding tools for the camshaft. The following should be done: VCT assembly mounting bolts, primary timing chain tensioner and chain should be taken out. For the models produced after the year 2011, make the engine clockwise rotate until the VCT units align themselves to 90 degrees of camshaft position and then remove the tubes of valve train oil and install the two special camshaft locking tools. Take out the principal timing chain and the second timing chains, if they are required. For installation make sure the timing marks are aligned, install new VCT unit center bolts and tighten to the specified torque value. Insert all the other parts in reverse manner, then turn the crankshaft by your hand at least two full turns and check whether there is any do not apply resistance. Last is to fit a new oil filter, replace engine oil and coolant and start the engine let it to warm up to examine any leakage.

Remove the timing chain cover and try to avoid turning the crankshaft.

These engines are difficult to work on and require special tools. Procedures involving the timing chains must be read carefully, and disassembly should use the special tools to avoid engine damage.