Jeep Engines - Oljeep

344 MOPAR PERFORMANCE PARTSEngine IdentificationThe 4.7L engine is stamped with the vehicles identificationnumber (VnU). This area is located at the right front side ofthe engine block. The engine build date code is included in theyellow bar code sticker on the oil fill housing. (Figure 6- 1).BLOCKThe cylinder block is made of cast iron. The block is aclosed deck design with the left bank forward. To providehigh rigidity and improved NVH, an enhanced compactedgraphite bedplate is bolted to the block. The block designallows coolant flow between the cylinders bores, and aninternal coolant bypass to a dual poppet inlet thermostat isincluded in the cast aluminum front cover.Structural Dust CoverThe structural dust cover is made of die cast aluminum andjoins the lower half of the transmission bellhousing to theengine bedplate. The structural cover provides additionalpowertrain stiffness and reduces noise and vibration.CRANKSHAFTFuel RequirementsFigure 6 - 7The 4.7L engine is designed to meet all emissionsregulations and provide excellent fuel economy andperformance when using high quality unleaded gasolinehaving an octane rating of 87. The use of premium gasolineis not recommended. The use of premium gasoline willprovide no benefit over high quality regular gasoline, and insome circumstances may result in poorer performance.Light spark knock at low engine speeds is not harmful toyour engine. However, continued heavy spark knock at highspeeds can cause damage and immediate service is required.Engine damage resulting from operation with a heavy sparkknock may not be covered by the new vehicle warranty.Poor quality gasoline can cause problems such as hardstarting, stalling and hesitations. If you experience thesesymptoms, try another brand of gasoline before consideringservice for the vehicle.The American Automobile Manufacturers Association(AAMA) has issued gasoline specifications to define theminimum fuel properties necessary to deliver enhancedperformance and durability for your vehicle.DaimlerChrysler recommends the use of gasoline that meetthe AAMA specifications if they are available.The crankshaft is constructed of nodular cast iron. Thecrankshaft is a cross-shaped four throw design with eightcounterweights for balancing purposes. The crankshaft issupported by five select main bearings with the No. 3serving as the thrust washer location. The main journals ofthe crankshaft are cross drilled to improve rod bearinglub'rication. The No. 8 counterweight has provisions forcrankshaft position sensor target wheel mounting.Thle select fit main bearing markings are located on the rearside of the target wheel. The crankshaft oil seals are onepiece design. The front oil seal is retained in the timingchain cover, and the rear seal is pressed in to a bore formedby the cylinder block and the bedplate assembly.TIMING DRIVE SYSTEMThe timing drive system (Figure 6-2) has been designed toprovide quiet performance and reliability to support a nonfreewheeling engine. Specifically, the intake valves arenon-free wheeling and can be easily damaged with forcefulengine rotation if camshaft-to-crankshaft timing isincorrect. The timing drive system consists of a primarychain and two secondary timing chain drives.The primary timing chain is a single inverted tooth type.The primary chain drives the large 50 tooth idler sprocketdirectly from a 25 tooth crankshaft sprocket. Primary chainmotion is controlled by a pivoting leaf spring tensioner armand a fixed guide. The arm and the guide both use nylonplastic wear faces for low friction and long wear. Theprimary chain receives oil splash lubrication from thesecondary chain drive and oil pump leakage. The idlersprocket assembly connects the primary and secondarychain drives. The idler sprocket assembly consists of twointegral 30 tooth sprockets and a 50 tooth sprocket that issplined to the assembly. The spline joint is a press-fit, antirattletype. A spiral ring is installed on the outboard side ofthe 50 tooth sprocket to prevent spline disengagement. Theidler sprocket assembly spins on a stationary idler shaft...