How many pistons do I need for my engine?

This piston is sold individually. For a complete engine rebuild on your 4.2L Jeep engine, you will need six pistons.

What does '.020 Over' mean for this piston?

'.020 Over' indicates that the piston is manufactured to be 0.020 inches larger in diameter than the original factory bore size. This is common when rebuilding an engine that has worn cylinder walls.

Is this piston compatible with California emissions standards?

No, this piston is not CARB approved and cannot be shipped to California due to emissions regulations.

Specifications

Brand: OMIX
Part #: 17427.22
UPC: 804314150433

OMIX

Omix Piston 4.2L .020 79-90 Jeep CJ & Wrangler

Name: Omix Piston 4.2L .020 79-90 Jeep CJ & Wrangler
Brand: OMIX
SKU: omix-omix-piston-4-2l-020-79-90-jeep-cj-wrangler-t14-443035
Price: 83.57 USD
Availability: BackOrder

$83.57

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Omix is known for Jeep replacement parts. This .020 overbore piston is for 4.2L Jeep engines from 1979-1990.

Key Features

Fits 1979-1990 Jeep CJ5, CJ7, Scrambler, J-Series Trucks, Cherokee SJ, Wagoneer SJ, Grand Wagoneer SJ, and Wrangler YJ models with 4.2L engines.
This is a cast piston that is 0.020 inches over the standard bore size.
Sold individually; six pistons are required per engine.
Replaces OE part number 8134441.020.
Backed by a limited 5-year warranty from Omix.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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About this part

Product Details

Omix has been a go-to for Jeep replacement parts for a long time, and they make solid components to get your rig back in shape. When you're rebuilding an engine, especially in a Jeep where you need every bit of power, replacing worn internal parts is key. This is a cast replacement piston designed for 4.2 liter engines that have been bored out an additional 0.020 inches over their original size.

This piston is built to help restore your engine's original performance after wear has taken its toll on components like the cylinder walls and rings. It's a direct replacement for the original part, meaning it fits right into your engine's setup. Remember, you'll need six of these for a complete engine rebuild, and they are sold individually.

This piston fits a wide range of Jeep models from 1979 through 1990, including CJ5, CJ7, Wrangler YJ, and J-Series trucks. Please note that this part is not CARB approved and cannot be shipped to California.