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Unread 08-22-2013, 09:47 PM   #1
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Join Date: Aug 2006
Location: Costa Rica
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Engine Swap Time? 1984 CJ7.....

Once Upon a time there was a guy (me), who drove his beloved CJ7 into a natural reserve in Costa Rica....

And the story could go on lovely, until I got nastly stuck in a mud pit (yes...we have plenty of those...even in the "cities"!..jeje)...And after really making the engine to get me out of there , and pulling out two small tress with the winch, I got out.

But the engine was never again the same. The mechanic said I probably blew a valve (or more). It is the venerable 256 I6...

So now, since it seems the cost will not be that different, I need to decide on whether fix it...or swap in something else.

The question: recommendations for engine swap? I am NOT INTERESTED in fuel efficiency, but I do not want to change the gear box...so It would just be a engine swap?

Any advice on never (90s decade) engines?

Thanks to all!!!


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Unread 08-22-2013, 10:19 PM   #2
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1985 CJ7 
Join Date: Sep 2008
Location: White Springs, Florida
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Welcome to the Forum, Frank!

What resources do you have down there? There are several options for rebuilding your 258, making it better in power and performance. Or, you could do a complete swap as you mention. I just did a 4.0 out of a '97 Cherokee, and it's amazing! It is also a pretty straight-forward swap, using your tranny and motor mounts. Check out the "Official 4.0 Swap thread" for ideas.
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Unread 08-22-2013, 10:58 PM   #3
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1981 CJ7 
Join Date: Jul 2009
Location: Bali, Indonesia
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A valve can be easy to fix, you can buy a second hand cylinder head or have the old valves replaced with new ones. Sometimes when over revving you can bounce the valve off the piston and bend the stem so they do not seal properly. One way to know for sure is to take off the cylinder head and have a look, a few hours work.

If you have set your heart on spending the money and time on an engine transplant you could have a look at the Novak Transmissions website, plenty of free info from guys who have seen a lot of Jeep engine and gearbox conversions.

For myself the 4.0l HO I6 is a natural choice, it will fit relatively easily as it is a development of the AMC258 and has considerably more power and fuel injection as well as being a reliable and long lived unit.

Others will no doubt disagree as you have no limit on fuel usage and a V8 is an obvious choice.
BagusJeep lives in Bali, the Land of Temples.
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1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE
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