Jeep 4781679AA Engine Exhaust Camshaft

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To replace the camshaft position sensor and target magnet you will need to take off the valve cover, timing belt, camshaft sprockets, and the rear timing belt cover. As a matter of fact the camshaft bearing cap was labeled in numbers and the position of these numbers were to be reinstalled on the cylinder head as shown. The outside bearing caps at each end of the camshafts should be put aside, followed by putting into an unscrewing operation on the rest of the caps gently so as not to twist camshafts, and the bearing cap bolts may be used as a lever as well. Gently raise the camshafts out from cylinder head and label as INTAKE and EXHAUST, to avoid confusion; extract front seal from each camshaft. Scrub the camshaft (camshafts) and the gasket surface and visually and with the micrometer check for wear or damage of camshaft bearing journals and the inside diameter of the bearing surface to measure oil clearance. Replace any worn components or if the camshaft is worn beyond usability, check the cylinder head too. Oil the camshaft(s) and the bearing journals and put back the camshaft in its rightful position but don't fit the rocker arms. Turn the crankshaft to install a dial indicator that measures the camshaft end play to minimum and maximum limit values. Subsequently, put the valve lash adjusters and the rocker arms in place, clean the cam shaft and the bearing journals and replace the camshafts back in their position with the timing marks being rightly aligned. They also clue in the bearing caps in the correct order and ensure applicable bearing cap got an RTV sealant applied and tighten the bolts to the designated torque. Lastly, put in new camshaft oil seals, timing belt and covers and associated parts, before the valve cover, and other parts must be replaced in a sequence as they were removed.

The camshaft, for instance, cannot be pulled out of its place when the cylinder head is still fitted in the car. Start by taking out all the cylinder heads and the rocker arm assemblies. Subsequent to this, remove the Camshaft position sensor and then gently pull the camshaft out through the rear opening of the cylinder head without harming the camshaft lobes or bearing journals in any way. Following removal, unscrew the/each seal from the camshaft(s) and wash them as well as the gasket surface. Camshaft lobes, and bearing journals, and seal contact surface should be checked for excessive wear or possible damage A camshaft end play that has increased or the camshaft bearing surface in the cylinder head has develop scoring or other unacceptable wear patterns. Check the camshaft bearing journal diameters with a micrometer while the inside diameter and face runout of the bearing surfaces in the cylinder head should be checked with an Artist PA-350 telescoping gauge. Deduct the journal measurement from the bearing measurement and establish the camshaft bearing oil clearance to compare this also. Clean the camshaft journals and apply clean engine oil to it and install the camshaft back in the cylinder head and the camshaft sensor. Mount a dial indicator to measure the camshaft end play and then check from the standard value of the camshaft. If any inspection reveals failure replace the camshaft, and in the case of worn out lobes also replace the rocker arms. Camshaft bearing surfaces in the head may be damaged or excessively worn or end play may be excessive so that cylinder head must be replaced. Before fitting, the journals of the camshaft should be cleaned before sliding some assembly lube or engine oil on the journals, lobes, and thrust areas and then slowly fitting the camshaft in the cylinder head. Place new camshaft oil seal and Camshaft Position sensor, cylinder head, rocker arm shaft assembly and timing belt with covers. Last but not the least step is to start the engine and look for oil leaks.

Use the bolts for leverage and gently tap them with a soft face mallet.

Use a long bolt in the camshaft sprocket bolt hole as a handle when removing the camshaft from the block, and carefully pull the camshaft out while supporting it to prevent damage to the bearings.

Use a long bolt in the camshaft sprocket bolt hole as a handle when removing the camshaft from the block, and carefully pull the camshaft out while supporting it to prevent damage to the bearings.

Install the rear bearing cap and tighten the bolts.

Repeat the process for the other rocker arms and remaining valves, ensuring each piston is at TDC on the compression stroke.

Use anaerobic-type sealant on the contact surfaces of the end caps before installing them and torque the fasteners in a criss-cross pattern.

Remove the rocker arm assembly.

Check the rocker arms and shafts for abnormal wear, pits, galling, score marks, and rough spots. Avoid attempts to restore rocker arms by grinding the pad surfaces, and replace any defective parts.

Molybase grease or engine assembly lube should be used to lubricate the camshaft bearing journals and cam lobes.