Omix Rocker Arm Kit 4.0L & 4.2L 83-06 CJ & WranglerBrand OMIX Part Number 17408. 15 Category Engine Components Rocker Arms Condition Brand New Original Manufacturer Packaging Over time all internal engine wear surfaces become worn. This is true for crankshaft journals, connecting rods, camshaft lobes, piston rings, bearings, etc. When rebuilding a worn out engine youll need to replace them all in order to regain the engines original performance. And, lets face it, Jeeps need all the power we can get.