Lincoln 8T4Z-6A257-B Camshaft Position Sensor

The VCT units have two timing marks on them, a triangle and a circle. When removing and installing the left-side VCT, use the circle marks. Starting with the left-side chain, install the left-side VCT units onto the camshafts with the circle timing marks at the 10 o'clock (intake) and 12:30 (exhaust) positions. Install new VCT unit center bolts and tighten the bolts to the torque. Slide the inner crankshaft sprocket over the end of the crankshaft. Place the left-side timing chain over the VCT units with the single colored links aligned with the circle timing marks on the VCT units at the 10 o'clock and 12:30 positions, then align the double colored links on the chain so the timing mark on the crankshaft sprocket is in between both links. Install the chain guide and bolts and tighten the guide bolts to the torque. Slide the left-side timing chain tensioner arm onto the pivot. Slide the tensioner piston out of the tensioner body. Using a vise, cover the vise jaws with covers or towels to prevent damage to the tensioner piston, then mount the piston vertically in the vise. Using a flat-blade screwdriver, push the ratchet mechanism down inside the tensioner piston, then rotate the screwdriver clockwise, one full turn until a click is heard. Note: If an audible click is not heard, the ratcheting mechanism is not locked in place. Remove the tensioner piston from the vise and insert the piston into the tensioner body until a retaining pin can be inserted through the hole in the tensioner body to lock the piston in the retracted position. Install the left-side tensioner and tighten the bolts to the torque. Make sure the end of the tensioner is properly engaged with the tensioner arm. With the tensioner piston properly engaged with the tensioner arm, remove the retaining pin. Install the oil pump chain over the crankshaft and oil-pump drive sprockets. Install the oil pump chain guide and bolts, then tighten the bolts to the torque. Install the oil pump chain tensioner and bolt, then tighten the bolt to the torque, then remove the retaining pin. Install the crankshaft mounting bolt, then rotate the crankshaft one full turn (360-degrees) until the keyway on the crankshaft is at the 11 o'clock position. Remove the crankshaft bolt and replace it with a new one, then slide the crankshaft sprocket onto the end of the crankshaft. Install the right-side VCT units onto the camshafts with the triangle timing marks at the 2 o'clock (intake) and 11 o'clock (exhaust) positions. Install new VCT unit center bolts and tighten the bolts to the torque. Place the right-side timing chain over the VCT units with the single colored links aligned with the triangle timing marks on the VCT units at the 2 o'clock and 11 o'clock positions, then align the double colored links on the chain so the timing mark on the crankshaft sprocket is in between both links. Install the chain guide and bolts and tighten the guide bolts to the torque. Slide the right-side timing chain tensioner arm onto the pivot. Slide the tensioner piston out of the tensioner body. Using a vise, cover the vise jaws with covers or towels to prevent damage to the tensioner piston, then mount the piston vertically in the vise. Using a flat-blade screwdriver, push the ratchet mechanism down inside the tensioner piston, then rotate the screwdriver clockwise, one full turn until a click is heard. Note: If an audible click is not heard, the ratcheting mechanism is not locked in place. Remove the tensioner piston from the vise and insert the piston into the tensioner body until a retaining pin can be inserted through the hole in the tensioner body to lock the piston in the retracted position. Install the right-side tensioner and tighten the bolts to the torque, making sure the end of the tensioner is properly engaged with the tensioner arm. With the tensioner piston properly engaged with the tensioner arm, remove the retaining pin.

Remove the left-side tensioner mounting bolts and tensioner.

Reinstall the crankshaft sprocket bolt and set the engine to TDC for cylinder number 1. These engines have three timing chains: The long primary chain drives the VCT sprockets (on each intake camshaft) and the water pump, while a smaller chain on each head drives the exhaust camshafts. Install the special camshaft holding tools (manufacturer tool no. 303-1248) on each cylinder head to lock the camshafts in the TDC position. Remove the VCT assembly mounting bolts from the rear cylinder head, then the front cylinder head. Remove the bolts, then remove the primary timing chain tensioner and tensioner arm. Remove the lower chain guide from the front cylinder bank. Mark the chain links opposite the timing marks on the camshafts (if not already marked), and remove the primary timing chain. Remove the upper chain guide from the front cylinder bank. If necessary, remove the crankshaft sprocket. If the secondary timing chains and camshaft sprockets are to be removed for inspection or another procedure, compress the tensioner(s) and insert a pin into the hole in the tensioner to hold it in the retracted position. Unscrew the bolts for the intake (VCT) and exhaust camshaft sprockets, then remove both sprockets and the chain as an assembly. Caution: Make sure the camshaft holding tool is in place and prevents the camshafts from turning while unscrewing the bolts. Also, new bolts must be used for reassembly. Remove the bolts and the secondary chain tensioners.

Insert a 3/8-inch-drive ratchet and extension into the hole at the back of the camshaft while loosening the phaser bolt(s).