4.2L 258 cui 6-cyl. AMC Engine Parts for Jeep Wrangler YJ
Engine Parts & Rebuild Kits for Jeep Wrangler YJ 4.2L AMC Inline-Six: Bearings, Gaskets, Pistons & More.
Restore the raw, low-end torque of your classic carbureted engine. We offer a comprehensive catalog for the 4.2L AMC block – from precision pistons and camshaft kits for the rotating assembly to premium aluminum replacement valve covers.
- Rotating Assembly: Standard & oversized pistons, main bearings, and rod bearing sets by Sealed Power and Enginetech.
- Valvetrain Spares: Sealed Power & Crown intake/exhaust valves, valve seats, Enginetech lifters, and Crown rocker arm bridge kits.
- Cam & Timing: Crown camshafts, camshaft bearings, and high-tensile timing chain kits by Enginetech.
- Airtight Sealing: Master engine gasket sets (upper & lower), head gaskets, and premium aluminum or plastic valve covers by Crown.
- Peripherals & Drive: Platinum Driveline flywheels with ring gears, high-volume oil pumps, harmonic balancers, and PCV valves.
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Overhauling Classic Cast-Iron Performance: Jeep Wrangler YJ 4.2L AMC Solutions.
The 4.2L AMC inline-six (258 Cui) is a legendary pushrod engine that powers the early model years of the Jeep Wrangler YJ from 1987 to 1990. Famous for its exceptional low-end torque resilience, this vintage carbureted block requires targeted mechanical attention after decades of trail use and heavy loading. Warped plastic valve covers, worn valve seats, or weak oil pressure are typical challenges found on early YJ models over time. Our specialized online inventory features professional-grade hardware to successfully restore factory compression, lubrication efficiency, and oil tightness back to your classic engine block.
Trusted Trail Quality: Sealed Power, Enginetech, Crown, and Platinum Driveline.
For internal mechanical restorations, we rely strictly on the industry-leading standards of Sealed Power and Enginetech. We stock high-durability pistons available in standard and oversizes, main bearings, camshaft bearings, and premium rod bearings complete with matching rod bolts and nuts from Crown and Mopar. Completely refresh your cylinder head assembly with premium intake/exhaust valves and high-tensile valve seats from Sealed Power, replacement hydraulic lifters from Enginetech, and factory-style rocker arm pivot bridge sets from Crown. Guarantee crisp timing and valvetrain synchronization with replacement camshafts from Crown Automotive, backed by Enginetech timing chain kits, chain guides, and timing cover gaskets.Permanently eliminate leaks with our comprehensive selection of Crown engine gasket sets (upper & lower), cylinder head gaskets, and oil pan seals. A highly recommended upgrade is the rigid Crown aluminum valve cover, engineered to permanently replace the warp-prone factory plastic cover (which we also stock for numbers-matching builds). Safeguard your rotating mass with a new harmonic balancer, high-volume Crown oil pumps (including pump gaskets), replacement oil pans, and comprehensive flywheel & ring gear packages from Platinum Driveline. Our complete range is finalized by Dorman oil pan drain plugs with seals, Standard PCV valves, Walker catalytic converter donuts, pre-formed carburetor air intake pre-heater hoses by Crown & Dorman, mechanical fuel pump seals, pilot bearings, and complete engine & transmission mount sets to completely isolate chassis vibrations.