Note: If your head has been modified (for example, the locator dowel pin holes have been drilled and tapped), our cover will not work for you.
The 258 engine was commonly used in 1971 to 1990 Jeep, AMC, and some industrial vehicles.
This valve cover fits 1981 to 1986 heads.
This valve cover also fits 1987 to 1990 heads if your engine came with the plastic valve cover. If your 1987-1990 engine came with an aluminum valve cover from the factory, our valve cover will not fit your head. Engines with the aluminum valve cover have the same gasket shape and bolt pattern as the 4.0 heads. Look at the Installation Instructions for a view of the gasket shape and bolt pattern on this valve cover and verify it is the same as the valve cover you have.
1980 and earlier heads usualy have a different bolt hole pattern so this PML valve cover will not fit those.
This valve cover has been installed on:
- CJ-5 Jeeps
- CJ-7 Jeeps
- Scrambler Jeeps
- Wagoneers
- YJ Wranglers
- Eagles
- AM General FJ8C (Ice Cream Truck)
Configurations vary. Always check your engine before ordering.
Dimensions: The cover has approximately 3.7 inches from the gasket to the inside top surface. Other dimensions not available.
Finishes: Read about finishes and construction of PML parts.
Installation Instructions: PML Jeep 258 Valve Cover Installation Instructions.
PML designed our valve cover for the AMC 258 (4.2 liter) straight 6 cylinder engine based on the original valve cover as it came from the factory. We use sand cast aluminum construction to provide strength and durability and a cast-in baffling system.
Benefits:
- Improved baffling
- Strong sand cast aluminum construction
- Thick, precision machined gasket flange for a uniform clamping force and secure seal
- Custom look
The cover includes a billet oil fill cap and has holes for PCV and breather.
The AMC Jeep 4.2 258 engine comes in four possible fastener configurations. The PML valve cover works with all possibilities and has provisions for the use of studded bridges and head bolts. Holes can be drilled for studded rocker arm bridges. Reference the Installation Instructions.
Baffling
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PML's baffling system allows the engine to breath better then most. We have some street applications that do not run any breathers on our covers, and there is no blow by. This baffling system works very well as compared to others since we run along the side wall and pick up lower than most.
Blow-by is not a situation that any valve cover can stop. PML's Jeep valve cover can reduce the oil mist somewhat since the design is longer and there is a elbow that will usually separate the oil from the air, allowing it to drip down. The baffling is an integral part of the casting so there are no rivets or screws to vibrate loose.
Stock Cover
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This is one of the stock OEM covers we used for development. The valve covers is from a 1986 Jeep CJ–7.
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