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Replacement engine parts for 1972-1986 Jeeps with 6-cylinder engines, such as the 232, 258 and 4.2L inline-six. The listings cover gaskets, bearings, pistons, timing parts, valves and filters for restoration and repair. This category suits owners of classic CJ and related models. Brands include Crown Automotive and Omix-Ada. Check the product pages for part numbers and engine notes, then compare the products below.

72-86 6 Cylinder Engine Parts

Showing 1–12 of 59 resultsSorted by popularity

Showing 1–12 of 59 resultsSorted by popularity

What this category covers

These listings serve older Jeeps and similar vehicles built from 1972 to 1986 with six-cylinder engines. The inline six was a long-running workhorse, and the parts here include internal components and the supporting items around them: connecting rod and main bearings, piston and ring sets, timing parts, valve train pieces, seals, mounts and filters.

Some of the listed parts are shared across the 4.0L, 4.2L and related engine families, so descriptions often list several displacements. Others, such as certain bearings or flywheels, are specific to a given engine or transmission.

How to match the part to the engine

  • **Confirm engine size.** Check the displacement printed in the product notes against your engine. The 4.2L and 4.0L, and the larger V8 or smaller four-cylinder sizes, are not interchangeable.
  • **Read bore and size.** Pistons, rings and bearings come in standard and oversize dimensions. Measure the cylinder bore and crankshaft journals before ordering.
  • **Check the transmission.** Flywheels differ for automatic and manual transmissions, so note what is listed, such as torque converter compatibility.
  • **Note year breaks.** Mid-run changes in this period sometimes alter bolt patterns, sensors and gasket shapes.

Use the engine code, build date and the manufacturer's specifications to confirm fitment for your exact year, make and model.

Rebuild and repair tips

  • Replace related wear items together. A timing kit goes better with a new front crankshaft seal and timing cover gasket.
  • Use new gaskets, seals and bolts where the manual calls for them, and clean mating surfaces thoroughly.
  • Measure clearances with a micrometer and plastigauge, not by feel, and follow the service manual's torque sequence and values.
  • Pre-lubricate bearings and prime the oil system before first start.
  • Fresh oil filters, drain plug washers and hoses are inexpensive additions while the engine is open.

A machine shop can bore cylinders, grind the crankshaft and check the block for cracks, which sets the sizes for new pistons and bearings. If you are not experienced with engine internals, consider professional installation, since mistakes in clearances or torque can ruin an engine quickly.

Older Jeeps may have been rebuilt before, so do not assume standard sizes. Verify before you buy, and use the manufacturer's data rather than guesses.

When ordering, record the engine code and the date on the block or tag, and photograph the old part. Compare bolt hole spacing, thickness and bore sizes before installing. Keep an organized set of bags for bolts, noting where each came from, because several fasteners look alike but differ in length.

Parts often used together include a timing kit with a front crankshaft seal, a piston set with rings and bearings, an oil pan kit with drain plug washers, and a new oil filter with fresh oil. Common mistakes are reusing old head or main bolts that the manual says to replace, skipping a check of crankshaft end play, and failing to break in new rings with varied loads and early oil changes. Keep the cooling system and fuel system in good shape too, since an older engine rebuilt on a worn radiator or carburetor will soon have problems.

Popular 72-86 6 Cylinder Engine Parts brands

72-86 6 Cylinder Engine Parts FAQ

Which engines are covered by this category?

The listings serve 1972-1986 Jeeps with six-cylinder engines, with many parts noting 4.0L and 4.2L inline-six fitment. Always compare the stated engine size with your own, since several displacements share a family but not every part.

How do I choose between standard and oversize pistons?

That depends on your cylinder bore after measuring or machining. A machine shop measures wear and bores to the next oversize if needed. Do not guess; confirm the bore and ring size before ordering parts.

Should I replace the timing chain and cover seal together?

It is common practice. The timing cover must come off to replace the chain or gears, so replacing the front crankshaft seal and cover gasket at the same time avoids doing the job twice.

Do these parts fit later 4.0L engines?

Some do, because the inline-six family continued, but many items differ by year. Check the notes on each product page and the manufacturer's specifications for your exact engine and year before relying on it.