3.8L & 4.2L 6-Cyl. Engine Parts for Jeep CJ5
Pistons, Timing Chain, Bearings & Engine Gaskets for Reliable Performance (1972-1983).
Why the 3.8L/4.2L Six-Cylinder in the Jeep CJ5 Needs Attention After Decades.
The AMC six-cylinder engine, offered in 3.8-liter and 4.2-liter displacement, was the backbone of the Jeep CJ lineup for decades and powered the CJ5 throughout its entire 1972-1983 production run. After so many years in service, pistons, piston rings, and connecting rod bearings show wear from continuous friction, while main bearings and crankshaft seals lose precision. The timing chain stretches over time, throwing off valve timing, and camshaft bearings along with hydraulic lifters suffer from inadequate lubrication when oil change intervals have lapsed. Cylinder head, valve cover, and oil pan gaskets harden and become porous, risking oil and compression loss. Rubber engine and transmission mounts also age over time, transmitting noticeable vibration into the cabin. Anyone driving their CJ5 off-road or restoring it should check these wear parts regularly and replace them in time.
- Cylinder Head, Valves & Gaskets: The cylinder head gasket and valve cover gasket reliably seal the combustion chamber and valvetrain.
- Timing Chain, Camshaft & Lifters: The timing set delivers precise valve timing, while the hydraulic lifter keeps the valvetrain running quietly.
- Pistons, Connecting Rod & Main Bearings: The standard-size piston set and connecting rod bearing set keep the crankshaft running true.
- Oil System & Engine Gasket Sets: The oil pump and complete engine gasket set secure lubrication and sealing for a full engine rebuild.
- Engine & Transmission Mounting: The motor mount and transmission mount set and the transmission insulator bushing for the Dana 300 transfer case dampen vibration.
- Intake, Exhaust, Clutch & Hardware: The clutch pilot bearing and exhaust manifold set round out a complete engine rebuild.
American Brand Quality for the Six-Cylinder.
The bulk of the range comes from Crown Automotive – covering gaskets, valve covers, and engine mounting –, complemented by pistons, piston rings, and bearings from Sealed Power and Enginetech, both known for American engineering expertise in engine building. PCV valves come from Standard Ignition, polyurethane engine mounts from Prothane, and the hot air duct hose from Dorman.
Your Partner for the 3.8L/4.2L Engine Rebuild.
Whether you need a single wear part or a complete engine rebuild, we're happy to advise you on torque specs, bearing clearances, and the correct assembly order, including compatibility questions for the related CJ7, CJ8, and Wagoneer/J-Series models. Your order ships from our warehouse as fast as possible, so your CJ5 is back on the road in no time.