Jeep 4781061AA Engine Camshaft

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To get access to the valve cover, timing belt, camshaft sprockets and the rear timing belt cover, first locate the camshaft bearing caps, they are numbered and they indicate the position on the cylinder head. Both the outer and the other bearing caps can be taken off; it is advisable to loosen the bolts gently for the avoidance of any kind of outer camshaft distortion and the working of the bolt in a circular pattern beginning with the center cap bolts. If the bearing caps are very tight then use the bolts as leverage and then hit the cap with a softer rubber headed hammer. That way store the caps for reinstallation some time in the future. Now, lift out of the crank case the camshafts, and label them as INTAKE and EXHAUST so they are not reversed. Take off the front seal from all the camshafts and check the conditions of the rocker arms and lash adjusters. Scrub the camshaft(s) as well as the gasket surface and see whether there are signs of wear or damages to the camshaft bearing journals, as well as measuring the camshaft bearing journal diameters and bearing surfaces for signs of scoring. Replace them with new ones when this is the case and also clean the cylinder head, preferably at an automotive machine shop. Coat the camshaft(s) and the cylinder head bearing journals with clean engine oil and then slot the camshaft back in its position but do not fit the rocker arms. Put back the rear bearing cap and torque up the bolts and with the use of dial indicator, check for camshaft endplay by taking the camshaft to full rear and front and measure the travel as compared to the standard limit set for it. To assemble, position the valve lash adjusters and the rocker arms, it is also important to clean and lubricate the camshaft and the bearing journals and then gently fit the camshafts back into their original positions as the timing marks should align. Bolt the few bearing caps excluding the no 1 and no 6 ending caps evenly to the standard optimistic torque. Use anaerobic sealant to sealing surfaces of bearing caps of No. 1 and No. 6 then fit the bearing caps and snug tight the bolts. Last but not least replace camshaft oil seal, timing belt, covers and related part; start the engine to look for oil leakage.

To get access to the valve cover, timing belt, camshaft sprockets and the rear timing belt cover, first locate the camshaft bearing caps, they are numbered and they indicate the position on the cylinder head. Both the outer and the other bearing caps can be taken off; it is advisable to loosen the bolts gently for the avoidance of any kind of outer camshaft distortion and the working of the bolt in a circular pattern beginning with the center cap bolts. If the bearing caps are very tight then use the bolts as leverage and then hit the cap with a softer rubber headed hammer. That way store the caps for reinstallation some time in the future. Now, lift out of the crank case the camshafts, and label them as INTAKE and EXHAUST so they are not reversed. Take off the front seal from all the camshafts and check the conditions of the rocker arms and lash adjusters. Scrub the camshaft(s) as well as the gasket surface and see whether there are signs of wear or damages to the camshaft bearing journals, as well as measuring the camshaft bearing journal diameters and bearing surfaces for signs of scoring. Replace them with new ones when this is the case and also clean the cylinder head, preferably at an automotive machine shop. Coat the camshaft(s) and the cylinder head bearing journals with clean engine oil and then slot the camshaft back in its position but do not fit the rocker arms. Put back the rear bearing cap and torque up the bolts and with the use of dial indicator, check for camshaft endplay by taking the camshaft to full rear and front and measure the travel as compared to the standard limit set for it. To assemble, position the valve lash adjusters and the rocker arms, it is also important to clean and lubricate the camshaft and the bearing journals and then gently fit the camshafts back into their original positions as the timing marks should align. Bolt the few bearing caps excluding the no 1 and no 6 ending caps evenly to the standard optimistic torque. Use anaerobic sealant to sealing surfaces of bearing caps of No. 1 and No. 6 then fit the bearing caps and snug tight the bolts. Last but not least replace camshaft oil seal, timing belt, covers and related part; start the engine to look for oil leakage.

The final step is to install the thrust plate and bolts, tightening them to the specified torque.

Measure the lobe height of each cam lobe on the intake camshaft, recording measurements to identify excessive variations; repeat for the exhaust camshaft, ensuring not to mix intake and exhaust measurements.

Determine the inside diameter of each bearing with a small hole gauge and outside micrometer or an inside micrometer, then calculate the bearing oil clearance.

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

Support the camshaft with V-blocks and rotate it while noting the indicator reading.

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.

Carefully pry the camshaft plugs from the rear section (transaxle end) of the cylinder head, taking care not to scratch or nick the camshaft.