Newbie / 4.0L Head Swap

Swaping 258 to 4.0, 4.0 parts to 258 etc!
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travwise
Posts: 2
Joined: February 21st, 2011, 8:58 pm
Vehicle Year: 1980
Vehicle Make: Jeep
Vehicle Model: CJ7

Newbie / 4.0L Head Swap

Post by travwise »

I recently purchased a 4.0L head from a 1995 Jeep Cherokee, casting number 7120. This was purchased from a junkyard, but tested - no leaks no cracks. I have read the most common articles on performing the swap, and as a new member to this site surfed what I could find. I have a couple of questions regarding this whole process - I apologize in advance if they sound stupid - just looking for some advice from the pros. Just to clarify I own a 1980 CJ7 with a 4.2, looking to swap the head at this time only. I am a first time builder, with a limited budget...

1. I have found conflicting information regarding whether or not you can/should use the 4.0 push rods, or the 4.2 push rods. Is there a "right answer" of do I just need to measure lifter preload after assembling the head?

2. The head I purchased from the junkyard is dirty and a little rusty in spots. Is it ok to clean of the head using a wire brush? I know the ultimate thing to do would be to take it to a machine shop for baking, and that is what I will do if I have to; again looking to complete this swap on a budget.

3. For those of you that have gone before me, is there anything I should know ahead of time? I am looking for "I wish I would have known that" type of stuff.

Thanks in advance for any that reply to this post. I am looking forward to learning all that I can.

- Travis
travwise
Posts: 2
Joined: February 21st, 2011, 8:58 pm
Vehicle Year: 1980
Vehicle Make: Jeep
Vehicle Model: CJ7

Re: Newbie / 4.0L Head Swap

Post by travwise »

Really? Not a single person has anything to say? What are there 5 people on this forum or what? Come on boys...
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SilverXJ
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Re: Newbie / 4.0L Head Swap

Post by SilverXJ »

I can only answer #2. You can clean it off with a wire brush, but don't use one of those scotch lock surfacers. They leave the head not flat. Reminds me of an article I found that someone purchased a used Hesco aluminum head.. then they showed them cleaning the head surface with one of them.. ugh..

How far do you want to clean it? You could take the springs and valves out, keeping them in order the way they go. Spray it with oven degreaser, brush it a bit, let it sit for a few minuets then hose it down with water. Dry it fast the cover it with WD40. Clean the valves the same way. You should also install new valve seals at the same time. Lube the valve guide and valve stems with 30w oil and install in same order.

However if you don't want to go that far I would recommend using Seafoam as a solvent. Spray the surface, let it soak and then brush it. Wipe it off. Before installing the head clean the surface with brake cleaner to remove any remaining oil.
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Jeep-Power
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Stroker Displacement: 4.3
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Location: Fort Mill, SC

Re: Newbie / 4.0L Head Swap

Post by Jeep-Power »

travwise wrote:Really? Not a single person has anything to say? What are there 5 people on this forum or what? Come on boys...

post it up in the threads that are established/ have more posts an you will be more likely to get some action.


I used the 4.2 pushrods--

I'd take it to a machine shop & have them magniflux & deck it, at least. The magniflux will assure that it is worth investing your time & $$ in, the decking will ensure it is nice & flat, in order to provide a good seal.


Any issues I had are in this thread!
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