Jeep Engines - Oljeep

302 MOPAR PERFORMANCE PARTSCAMSHAFTCamshaft and Valve GearThe 4.2L engine uses a cast iron camshaft with intake andexhaust valve lifts of 10.29 mm (0.405”), intake andexhaust cam lobe lifts of 6.43 mm (0.253”), and intake andexhaust durations of 262”.The camshaft is supported by four steel-shelled, Babbitlinedbearings which have been pressed into the block andline reamed. The camshaft bearings are step bored, beinglarger at the front bearing than at the rear, to permit easyremoval and installation of the camshaft. All camshaftbearings are lubricated under pressure.Note: It is not advisable to replace camshaft bearings unlessyou are equipped with special removing, installing andreaming tools.Camshaft end play is maintained by the load placed on thecamshaft by the oil pump and distributor drive gear.The helical cut of the gear holds the camshaft sprocketthrust face against the cylinder block face. Therefore,camshaft end play is zero during engine operation.Jeep Gear DrivesReplace conventional Jeep timing chain and gear sets andeliminate chain induced cam timing fluctuations with thisMopar Performance Parts dual idler gear drive camshaftcenterlining drive system. Rugged and durable for off-roadapplications. Fits all 4.0L, 4.2L, and 2.5L Jeep engines.PS249009RemovalJeep gear drives.Warning! The coolant in a recently operated engine is hotand pressurized. Release the pressure before removing thedraincock, cap and drain plugs.1.2.3.4.5.6.Disconnect the battery negative cable.Drain the cooling system.Note: DO NOT waste reusable coolant. If the solutionis clean, drain it into a clean container for reuse.Remove the radiator. Refer to the service manual forthe proper procedure.Remove the air conditioner condenser andreceiveddriver assembly as a charged unit, if equipped.Refer to the proper service manual for additionalinformation pertaining to the N C system.Remove the distributor and ignition wires.Remove the fuel pump. Refer to the proper servicemanual for the procedure.7. Remove the cylinder head cover. Refer to CylinderHead Cover Removal, ‘Cylinder Head’ section, for theprocedure.8. Remove the capscrews, bridge and pivot assemblies,and rocker arms.9. Alternately loosen each capscrew one turn at a time toavoid damaging the bridges.10. Remove the pushrods. Position all components on aworkbench in the same order as removed to facilitateinstallation at the original locations.1‘1. Remove the cylinder head and gasket. Refer toCylinder Head Removal, ‘Cylinder Head’ section ofthis chapter, for the procedure.1’2. Remove the hydraulic valve tappets. Refer toHydraulic Valve Tappet Removal, in this section, forthe procedure.13. Remove the vibration damper. Refer to VibrationDamper Removal, ‘Crankshaft’ section of this chapter,for the procedure.14. Remove the timing case cover. Refer to Timing CaseCover Removal, ‘Crankshaft’ section of this chapter,for the procedure.15. Remove the timing chain and sprockets. Refer toTiming Chain and Sprockets Removal, ‘Crankshaft’section of this chapter, for the procedure.16. Remove the grille. Refer to the proper service manualfor the procedure.17. Remove the camshaft.Inspection1.2.3.4.5.Inspect the cam lobes for wear.Inspect the bearing journals for uneven wear patternor finish.Inspect the bearings for wear.Inspect the distributor drive gear for wear.If the camshaft appears to have been rubbing against thetiming case cover, examine the oil pressure relief holes inthe rear cam journal to ensure that they are free of debris.Installation1. Lubricate the camshaft with Mopar Super OilConditioner, or equivalent.2.Carefully install the camshaft to prevent damage to thecamshaft bearings.T - T 1