Jeep Engines - Oljeep

204 MOPAR PERFORMANCE PARTSb. The oil level in the pan should never be above the“full” mark or below the “add oil” mark on the oildipstick. Either of these two conditions could beresponsible for noisy tappets. Check the oil levelafter the engine reaches normal operatingtemperature. Shut off the engine, allow 5 minutesto stabilize oil level, then check the dipstick. Makesure the vehicle is on level ground.i. Oil Level Too Highii.If the oil level is above the “full” mark on thedipstick, it is possible for the connecting rodsto dip into the oil while the engine is runningand create foam. Foam in the oil pan wouldthen be fed to the hydraulic tappets by the oilpump, causing them to lose length andallowing valves to seat noisily.Oil Level Too LowLow oil level may allow the oil pump to takein air which, when fed to the tappets, causesthem to lose length and allows valves to seatnoisily. Any leaks on the intake side of thepump through which air can be drawn willcreate the same tappet action. When tappetnoise is due to aeration, it may be intermittentor constant, and usually more than one tappetwill be noisy. When oil level and leaks havebeen corrected, the engine should be operatedat fast idle for sufficient time to allow all ofthe air inside of the tappets to bleed out.2. Tappet Noise DiagnosisTo determine the source of tappet noise, operate theengine at idle with valve covers removed. Feel eachvalve spring or rocker arm to detect noisy tappet. Thenoisy tappet will cause the affected spring andorrocker arm to vibrate or feel rough in operation.Note: Worn valve guides or cocked springs aresometimes mistaken for noisy tappets. If this is thecase, noise may be dampened by applying side thruston the valve spring. If noise is not appreciably reduced,it can be assumed the noise is in the tappet. Inspect therocker arm pushrod sockets and pushrod ends for wear.Valve tappet noise ranges from light noise to a heavyclick. A light noise is usually caused by excessive leakdownaround the unit plunger which will necessitatereplacing the tappet, or by the plunger partially stickingin the tappet body cylinder. A heavy click is caused eitherby a tappet check valve not seating, or by foreignparticles becoming wedged between the plunger and thetappet body causing the plunger to stick in the downposition. This heavy click will be accompanied byexcessive clearance between the valve stem and rockerarm as the valve closes. In either case, the tappetassembly should be removed for inspection and cleaning.3. RemovalRetain all components in the same order as removed tofacilitate installation in their original positions.a.b.C.d.e.f.Remove the cylinder head cover. Refer toCylinder Head Cover Removal, ‘Cylinder Head’section of this chapter, for the procedure.Remove the bridge and pivot assemblies and rockerarms by removing the two capscrews at each bridge(Figure 2-62). Alternately loosen each capscrewone turn at a time to avoid damaging the bridges.Remove the pushrods (Figure 2-62).Remove the intake and exhaust manifolds. Referto the service manual for the proper procedure.Remove the cylinder head and gasket. Refer toCylinder Head Removal, ‘Cylinder Head’ sectionof this chapter, for the procedure.Remove the tappets through the pushrod openingsin the cylinder block.4. Disassembly, Cleaning and InspectionPlace the components of each tappet in a separate location.This will greatly assist in the installation operation.a.b.c.d.e.f.Release the snap ring (Figure 2-72).Remove the following from the tappet body(Figure 2-72):i. Plunger capii. Metering valve...111. Plungeriv. Check valve assemblyv. Plunger return springClean the components of each tappet assembly incleaning solvent to remove all varnish, gum andsludge deposits.Inspect for indications of scuffing on the side andbase of each tappet body.Inspect each tappet base for concave wear with astraightedge positioned across the base.If the base is concave, the corresponding lobe onthe camshaft is also worn. Replace the camshaftand tappets.......T --I ’7