Jeep Engines - Oljeep

T ^ T 74.0L POWER TECH IN-LINE 6 (CAMSHAFT AND VALVE GEAR) 1994. Check rocker arm-to-valve tip relationship foralignment. Improper alignment can place undue sideloads on the valves, causing rapid valve guide wear.Rocker shaft spacers or grinding the rocker can be usedto move the rocker arm up or down the shaft to align iton the valve tip.Valve Refacing1. Use a valve refacing machine to reface the intake andexhaust valves to the specified angle.2.After refacing, a margin of at least 0.787 mm (0.031")must remain (Figure 4-36). If the margin is less than0.787 mm (0.031"), the valve must be replaced.Installed Height and GuideThe installed height can be checked quite easily. However,with high lift camshafts, more care should be taken thanjust measuring the outer spring height. The inner springshould be checked, too. The solid height of the outer spring,inner spring and the damper should also be checked. Mostsprings, including production and dual springs (outer) willgo solid at 1.1-1.2". Race springs will go solid at l", whiledual springs (inner) will go solid at less than 1 ".Note: Be sure to check inner and outer springs separately.While measuring the installed spring height, also check thekeeper-to-guide clearance. If inadequate clearance is found,the guide will have to be shortened. The easiest way to dothis is by grinding it. If dual springs are used, the innerspring seat may have to be dropped even with the outerspring seat, and the outside diameter of the guide itselfdecreased for the inner spring to fit over it.InstallationCORRECTNO MARGININCORRECT J9009-78Figure 4 - 36Valve Spring Tension TestUse a valve spring tester and a torque wrench (Figure 2-66)to test each valve spring for the specified tension value.(Refer to 4.0L Engine Specifications, 'Engine Assembly'section of this chapter, for valve spring tension values.)Replace valve springs that are not within specification.Note: Most people in the performance industry use asimpler, more common valve spring tester that does notrequire a torque wrench to arrive at the tension (load).These simpler to use valve spring testers allow you tocompress the spring to the height (open or closed) that youwant to measure and then read the load directly off a scalethat is on the tester itself. The key to valve spring testers isto obtain the correct installed height.This procedure can be done with the cylinder head installedon the block.Caution: Install oil seals carefully to prevent damage fromthe sharp edges of the valve spring lock groove.1.2.3.4.5.6.7.8.9.Thoroughly clean valve stems and valve guide bores.Lubricate the stem lightly.Install the valve in the original valve guide bore fromwhere it was removed.Lightly push the valve seal over the valve stem andvalve guide boss. Be sure the seal is completely seatedon the valve guide boss.Install valve spring and retainer.Compress the valve spring with a valve springcompressor tool and insert the valve locks. Release thespring tension and remove the tool. Tap the spring fromside-to-side to ensure that the spring is seated properlyon the cylinder head.Release air pressure and disconnect the air hose.Remove the adapter from the spark plug hole andinstall the spark plug.Repeat the procedures for each remaining valve springto be removed.Install the pushrods. Ensure the bottom end of each rodis centered in the plunger cap seat of the hydraulicvalve tappet.