Jeep Engines - Oljeep

264 MOPAR PERFORMANCE PARTSCamshaft into Block1.2.3.4.5.Before installation, the camshaft and tappets should beliberally coated with Mopar Engine Oil Supplement.This lubricant will stick to the surfaces withoutdraining off and will prevent scuffing when the engineis fired up for the first time. It has been determined thatthis is when the most camshaft damage takes place.When installing the camshaft sprocket, use at leastGrade 8 bolts, along with Loctite and safety wire. It ispossible for high speed engine harmonics to causethese bolts to loosen if precautions aren’t taken.Because of production tolerances, it is possible for thecrankshaft-to-camshaft relation to be several degreesoff, either advanced or retarded. It is important that thistiming be correct to produce maximum performance.While the engine is still without the head, the timingmarks on the crankshaft damper and the timing chaincover should be checked for accuracy of the “0’ TDCmark.Advancing or retarding a camshaft should only be doneto install the camshaft at its designed centerline. It isvery important to have the centerline correct. Mostcamshafts will have the design centerline stated as partof the specifications along with duration and lift. If itisn’t given, it can be calculated (refer to ‘Camshaft andValve Gear’ section of this chapter). Advancing orretarding a camshaft from its designed centerline is notrecommended because it will reduce the overallefficiency of the engine.Cylinder Head onto BlockWhen the block was honed using a honing plate, a certaincylinder head bolt thread engagement depth was used for eachbolt. It is important that the cylinder head be attached usingthe same thread engagement depth as the honing plate did.With the block ready to be assembled, the cylinder head andintake and exhaust manifolds can be checked in thepreliminary stages of assembly.Use the correct torque sequence when installing head bolts(refer to Installation, ‘Cylinder Head’ section of thischapter for complete procedure). Be sure to torque the boltsa second time after you’ve run the engine.Valve Gear onto EngineWith the camshaft in the block and the head installed, theactual valve lift measured at the valve retainer can bechecked. The camshaft lift multiplied by the design rockerarm ratio should yield the valve lift. However, this is not thecase in an actual engine. The actual rocker arm ratio will beless than the design rocker ratio which is typically 1.5 forwedge engines. This will cause the valve lift to be less thanthe number that is calculated. This is due to the rocker armratio itself plus the effect of the geometry of the head.“Blueprinted” mechanical rocker arms (those with an exactdesign ratio) are available for most engines from varioushigh performance machine shops.Intake ManifoldThe intake manifold should be checked for port alignment.The intake manifold’s angle should be the same as thecylinder head and it should fit such that with the gasketinstalled the intake manifold bolt holes line up.The intake manifold attaching holes in some cylinder headsare shallow. Check to be sure the manifold screws areproperly torqued and that the manifold is actuallycompressing the gaskets. If the holes are shallow, a rathersevere oil leak may result.Carburetion System (if equipped)The carburetion system directly affects the cylinder head,but only to a minor degree. All the same, the carburetionsystem is rated as the number two engine building decisionbecause of its indirect effect on camshaft selection. In manycastzs, the carburetion system is determined by the rules ofthe governing body that runs the race track. Without that toguide us, a single 3-barrel is preferred because of itssimplicity.Oiling SystemRefer to ‘Oiling System’ section of this chapter for detailedinformation and parts listing.Accessory DrivesA typical drag race vehicle has a very limited accessorydrive at the front of the engine. It may consist totally of onedry sump pulley and belt. This is very simple and has neverbeen known to cause any problems except for those whoforget to charge their batteries between runs! However,othler types of race vehicles typically have a water pumpdrive, an alternator drive, a power steering pump drive,and/or a dry sump drive. If you take the “stack it on thefront and use a longer bolt” approach, you could have someproblems, especially during long, high speed races. You’dlike to keep the drives as close to the front of the engine asyou can. However, you can’t take the drag racing approacheither. If you use the water pump drive to drive thealternator, you can save one separate drive. The powersteering can be driven off the water pump so that it doesn’tload the crankshaft and push the bolt out further. Thissirnple approach can take several inches off the bolt length.Valve ClearancesPrloper valve clearances are very important to prevent bentor broken valves. Valve clearances to be checked includevalve-to-valve, valve-to-piston, valve tip-to-rocker arm tip,and valve-to-block. For complete information, refer to‘Camshaft and Valve Gear’ section of this chapter.