Ford F77Z-6268-BC Chain Assembly

To access the timing chain, you need to disconnect the negative terminal on the battery and turn the engine to TDC number one cylinder then rotate the crank well over 350 degrees such that while the number one piston is slightly before TDC. Withdraw the right valve cover and fit a dial indicator to the cylinder head with the plunger pointing at the number one rocker arm. Manually rotate the crankshaft until the number one piston is at TDC then observe the dial indicator to take up the initial play at the right side of the timing chain and zero the dial indicator. Gradually rotate the crankshaft backwards in anti-clockwise direction until there is oscillation on the dial indicator, measure here how far piston has moved away from TDC mark, if more than 10 degrees a new timing chain and sockets are required. With timing chain cover off, turn the engine to have the number one piston at Top Dead Centre on the compression stroke and rotate the crankshaft in an anti-clockwise direction until you feel a tight feel on the left side of the chain. Choose a reference mark on the block and scribe the length to the chain and replace the bolt in the crankshaft pulley and rotate the crankshaft to tighten up the left side. Find the distance from the reference mark to the chain; if the deflection is over 1/2 inch, replace the timing chain assembly. Check for signs of wear and or damage on the camshaft and crankshaft gears as these may lead to failure of the timing chain. Make sure that the number one piston is on the top dead centre before removing the timing chain cover, to prevent the crankshaft from rotating during pulley removal. Timing mark on the crankshaft and camshaft sprockets must be aligned prior to the removal of camshaft sprocket mounting bolt which after would unclasp the chain from the both sprockets. You will need to wash the cover and the faces of the engine block, and inspect them for warping around bolt holes; change the oil seal if needed. Fit the Woodruff key into the keyway in the crankshaft sprocket; the sprocket should be fitted on to the crankshaft without hammering. Place the crankshaft in such a way that the key is on the top followed by placing the chain on the camshaft sprocket and rotate it to make the timing mark to face down. Make sure that a line can be drawn through camshaft, the camshaft timing mark, the crankshaft timing mark, and the centre of the crankshaft before fixing the sprocket of the camshaft with the help of the camshaft sprocket bolt and a thread locking compound. Install the timing chain cover and crankshaft pulley back and screw the rest parts in their proper sequence of installation after refilling the coolant and checking the oil level the engine shall be tested for leakage.

To check camshaft end play, must first remove the timing chain cover and the rocker arm shafts. Rotate the camshaft as far back in its bore as possible or as far forward as possible and then install a dial indicator so that its index is on sprocket bolt with the indicator moved to zero. You can now pry the camshaft forward using a large screwdriver or pry bar between the camshaft sprocket and the block; then, compare a dial indicator reading taken at the beginning and at the end of this operation to the amount of end play recommend and if the end play exceed the camshaft thrust plate should be replace. For timing chain and tensioner inspection, too, ease off the timing chain cover and timing chain tensioner, noting a reference mark on the block. Twist the crankshaft anti-clockwise until the right side of the chain is tight then measure from the reference point to the right side. If the deflection is still present, turn the crankshaft clockwise to take up any lateral movement on the left side and recheck; the amount of either will depend on how much it changed to determine the degree of slack in the timing chain and, if severe enough, it should be replaced. It is the component that should be checked for any signs of wear or damage and if so should be changed; this part should be retracted before it is engaged. To remove the chain and sprocket you will have to drain off the cooling system and the engine oil, then remove the oil pan, the drive belt and finally remove the timing chain cover. Synchronize the timing marks by rotating the crankshaft, note/unscrew or remove the timing chain tensioner or camshaft sprocket bolt and/ or take off the sprockets and the chain but do not facilitate the crankshaft or the camshaft. If required then it is possible to take out chain guide bolts and then turn out the guide. For refitting, align the crankshaft and the camshaft sprocket timing marks, fit the crankshaft pulley if removed and tighten the guide bolts on the chain if removed. Position the sprockets in such a manner that their timing marks face each other, then fit them onto the crankshaft and the camshaft in order; confirm that the chain is central and not loose.Apply an additional 15-35 m/kg or ft/lb on the camshaft sprocket bolt, then compress the tensioner pad with the help of a sharp-tipped probe tool in order to pull back the tensioner into the required position.Last is to fit the timing chain tensioner and fasten it's nuts and bolts, after reinstalling other parts in reverse order start the engine and look for leakage of oil or coolant.

Remove the left valve cover and loosen the number 5 cylinder exhaust valve rocker arm, rotating it aside. Mount a dial indicator on the end of the pushrod to detect valve lifter movement. Turn the crankshaft clockwise until the number 1 piston is at Top Dead Center, ensuring the damper timing mark points to TDC on the timing degree indicator, which will take up slack on the right side of the chain. Zero the dial indicator and slowly turn the crankshaft counterclockwise until the slightest movement is seen on the dial indicator, checking how far the damper TDC timing mark has moved away from the pointer. If the reading on the timing indicator exceeds 6 degrees, replace the timing chain and sprockets. Next, turn the crankshaft clockwise until the number one piston is at Top Dead Center, disconnect the negative cable at the battery, and remove the timing chain cover. Unbolt the camshaft sprocket, ensuring the engine does not turn during bolt removal, and carefully remove the sprocket with the chain still attached. Pry the crankshaft sprocket off, taking care not to lose the small crankshaft key, and check the timing chain and sprockets for visible wear and damage, replacing them as a set if necessary. For installation, slide both sprockets and the chain onto the camshaft and crankshaft with the timing marks aligned, tapping the crankshaft sprocket into place with a brass drift and hammer. Install the camshaft bolt and washer, tightening the bolts to the specified torque, ensuring the camshaft bolt's drilled oil passage is open before installation, and do not substitute any other type of bolt. Apply oil to the timing chain and sprockets, then install the timing chain cover and the remaining components removed for installation.