Mercury 7T4Z-6250-B Camshaft

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When unbolting the rear bank cylinder head of the 3.0L V6 engine, the timing chain of the rear cylinder bank should be disconnected, and the position of each camshaft cap should be noted, and the caps should be marked if necessary to avoid confusing them. Slowly and equally undo the camshaft bearing cap bolts from the order in which the caps were tightened, and pull off the caps, slightly striking them if possible. Camshaft bearing cap and cylinder heads should be replaced at their original positions. When removing the intake and exhaust camshafts, use a marker to place reference points that will allow you to put them in the same positions during the assembling phase of the work and the same goes for the rocker arms that should be placed in a suitable container. Remove the hydraulic lash adjusters from their bores, ensure that you arrange them for reuse later. In the case of the front bank, rotate the crankshaft so that the keyway is at the 11 o'clock position, remove the timing chain, the water pump pulley, and as in the case of removing all the front camshafts, rocker arms, as well as lash adjusters. Each of the hydraulic lash adjusters must be checked for wear and to ensure there is no tapering of the diameters. Check rocker arms for cracks and camshaft lobes for wear; measure camshaft bearing journals for wear. For oil clearance check, cleaning of bearing surfaces, fitting of camshaft with plastigage and measurement of flattened width of plastigage only. Any bearing clearance which has gone beyond the specified tolerances must be corrected with the replacement of the camshaft or the cylinder head if required. To install, applying oil on the rocker arms, hydraulic lash adjusters and camshafts and placing it to its original position, tighten the bearing cap at the specified torque first at the upper then at the lower camshaft. Replace the timing chain and cover and put oil into the crankcase and check if there is any oil leak after connecting the battery. The 3.5L V6 engine requires special camshaft holding tools. Every timing chain and VCT assemblies should be deleted with the camshaft cap position An erector seat should also be used to lift the camshafts from the cylinder head. Lifters should be checked for wear and tear and should deb ideally able to operate smoothly. Reinstall lifters, correct any valve-lifter clearances that are required while lubricating them. For 2012 and earlier models, camshafts and bearing caps should be lubricated and fitted and the valve clearance checked once more. For camshafts updates to secures and for all 2013 and later models, with new seals in the grooves of the camshafts, lubricate the bearing journals and its position which should be followed in putting the bearing caps. Recheck the valve clearances, needing to rotate camshaft for the VCT unit putting back, and then assemble, with putting back of the primary timing chain and oil tubes, make sure that all the steps are in reverse order. It is advisable to fill the cooling system, change the oil and put on a new oil filter before turning on the engine.

If the camshafts have to be removed for any procedure, it is better to check the valve clearances prior to disassembly in order to order new lifters, if needed, from a dealership. Start with the timing chain removal-pay attention to the shape of the cam lobes of the no. 1 cylinder and slots in the ends of the camshafts. Disassemble the camshaft phaser and the sprockets that accompanies it with the help of an Allen wrench, and mark the parts that are to be reattached, with indelible ink. While holding the cam shaft in position, suspend the camshaft sprocket bolt just as much as necessary to allow loosening. Secondly there is need to, unsurprisingly, remove the Variable Camshaft Timing (VCT) solenoid fasteners and the front camshaft bearing cap bolts which lifts the cap off the two camshafts. Identify and indicate the bearing caps so that the right ones will be placed back in the correct position and with the correct orientation. Some of the camshaft bearing cap bolts may be extremely tight due to the pressure of the valve springs; as such, they can be removed progressively while loosening the tension of the springs, then remove the caps and take out the camshafts, noting that the exhaust camshaft has a reference lobe. It is important only to store each of the lifters in a clean container without swapping any of them. Look for worn out camshafts and lifters, check on the diameters of the lifters, and also look for signs of damages. If the engine contains loud noise at the valve components, setting the valve clearances could be called for. ScrollView the camshaft lobes and bearings for flatness and wear and measure the diameters of the journal. Measuring the bearing journal running clearance by Plastigage and if any clearance is beyond the service means, replace the camshaft or cylinder head. To get an indicator mark, clean those bearing surfaces and then to measure the camshaft endplay use a dial indicator. When installing ensure that the crankshaft is at the T DC; oil the lifter bores and the lifters and then place them back in their positions. Lubricate the camshaft bearing surfaces and then fit camshafts are to be in proper alignment. Remove all the dirt on the surfaces that are to be mated this is followed by application of RTV sealant on to the exhaust camshaft rear bearing cap. Place the camshaft bearing caps as indicated by the marked positions and then fasten them in the manner that was described above. Last, attach the variable camshaft timing solenoids, the phasers, the sprockets after which follows the reassembly of the timing chain, phaser and the re-timing of the valves, before fitting the valve cover the valve clearances should also be checked.

If the camshafts have to be removed for any procedure, it is better to check the valve clearances prior to disassembly in order to order new lifters, if needed, from a dealership. Start with the timing chain removal-pay attention to the shape of the cam lobes of the no. 1 cylinder and slots in the ends of the camshafts. Disassemble the camshaft phaser and the sprockets that accompanies it with the help of an Allen wrench, and mark the parts that are to be reattached, with indelible ink. While holding the cam shaft in position, suspend the camshaft sprocket bolt just as much as necessary to allow loosening. Secondly there is need to, unsurprisingly, remove the Variable Camshaft Timing (VCT) solenoid fasteners and the front camshaft bearing cap bolts which lifts the cap off the two camshafts. Identify and indicate the bearing caps so that the right ones will be placed back in the correct position and with the correct orientation. Some of the camshaft bearing cap bolts may be extremely tight due to the pressure of the valve springs; as such, they can be removed progressively while loosening the tension of the springs, then remove the caps and take out the camshafts, noting that the exhaust camshaft has a reference lobe. It is important only to store each of the lifters in a clean container without swapping any of them. Look for worn out camshafts and lifters, check on the diameters of the lifters, and also look for signs of damages. If the engine contains loud noise at the valve components, setting the valve clearances could be called for. ScrollView the camshaft lobes and bearings for flatness and wear and measure the diameters of the journal. Measuring the bearing journal running clearance by Plastigage and if any clearance is beyond the service means, replace the camshaft or cylinder head. To get an indicator mark, clean those bearing surfaces and then to measure the camshaft endplay use a dial indicator. When installing ensure that the crankshaft is at the T DC; oil the lifter bores and the lifters and then place them back in their positions. Lubricate the camshaft bearing surfaces and then fit camshafts are to be in proper alignment. Remove all the dirt on the surfaces that are to be mated this is followed by application of RTV sealant on to the exhaust camshaft rear bearing cap. Place the camshaft bearing caps as indicated by the marked positions and then fasten them in the manner that was described above. Last, attach the variable camshaft timing solenoids, the phasers, the sprockets after which follows the reassembly of the timing chain, phaser and the re-timing of the valves, before fitting the valve cover the valve clearances should also be checked.

Turn the crankshaft 1-2/3 turns (clockwise) until the crankshaft keyway is at 11 o'clock.

Withdraw each lifter in turn and place them in numbered containers, ensuring they are not interchanged.

No, this procedure can only be done with the engine removed.

The remainder of the reassembly procedure, including replacement of the timing chain and setting the valve timing, is as described in Section 8.

These engines are difficult to work on and require some special tools. On any procedure involving the timing chains, the steps must be read carefully and disassembly must proceed using the special tools, otherwise damage to the engine will result.