Chrysler 4781061AA Engine Camshaft

In the case of a 3.5L V6 engine, it has been replaced by a 3.3L and 3.8L V6 engine and this procedure applies to these engines. Due to the limitations of space to gain access to the camshaft, it is relocated if the engine is in the vehicle; for this procedure the engine has to come out of the vehicle and mounted on a stand. First take out the timing chain and sprockets, the lifters and the push rods. After that, remove the bolts and the camshaft thrust plate from the engine block. When pulling the camshaft out of the block use a long bolt fit in the camshaft sprocket bolt hole and pulling the camshaft out in a manner that way you're not damaging the bearings. Following removal, wash the camshaft in solvent and dry it after; in doing so, check the bearing journals for wear, pitting or signs of seizure and if there are they both the camshaft and bearings will require replacement. Replacing camshaft bearings may not be too complicated but the actual operation requires special tools and knowledge, so if you think that you are not capable of doing this, then you should take the engine block to the automotive machine shop. Insert a micrometer and check each bearing journal for excess wear or being out-of-round and check the lobe height of each cam lobe on the intake camshaft for variations; repeat the same using the exhaust camshaft but avoiding mixing the intake and exhaust measurements. The lobes of the camshaft should be checked for heat checks, scores, chipped, pitted or worn areas or surfaces; if all is well with the lobes, and within limits, then a camshaft can be used again. Check the inside diameter of each bearing using a small hole gauge and outside micrometer or inside micrometer and find the bearing oil clearance and if large new bearings will be needed. Wash the lifters but; make sure that the lifters are not mixed together, and inspect the lifter walls, pushrod seats, and feet for scuffing, scored, and wear marks. If new lifters are being installed a new camshaft has to be installed at the same time, and never put used lifters on the engine unless at the same time the original camshaft is put on. Inspect the rollers gently for signs of wear and harms and then to make sure that the rollers rotate freely with minimal side to side movement. For installation, the camshaft bearing journals and the cam lobes should be lubricated with moly-base grease or engine assembly lube, then after sliding in the camshaft into the engine, it should be supported near the block to avoid scraping or nicking the bearings. At last, fit the thrust plate together with the bolts, as per the torque setting and read on to fit the timing chain.

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.