Options After Blown Head Gasket

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boskoarmstrong

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Dec 1, 2020
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Texas
Howdy Y'all,

I have a '87 YJ with the 4.3, which just a couple weeks ago overheated for an unknown reason and blew a head gasket on the highway. Upon further inspection, at least one of the pistons is shot, so we're gonna have to do some engine rebuilding. Now, I am not planning on doing this myself, because as much as I would love to, I do not yet have the skills required to not make this job a massive never-ending money pit. We're trying to spend as little as possible, but I am wondering if this is an opportunity to just go ahead and swap the engine. Do any of y'all have any experience with this? Would it be worth it to try and swap, or should I just stick with a rebuilt 4.3? Thanks in advance!

- Bosko

EDIT: 4.2L, I promise I'm not dumb
 
Your cheapest route will be finding a used, running 4.2 and dropping it in. However, some engine swaps are almost as economical. The cheapest one I've found is still a version of the one I did: Swapping in the engine, transmission and T-case from an early 90s S10 Blazer with the 4.3L V6 and 700R4 automatic. The reason it's cheap is that the Blazer used a variant of the yj transfer case, so your drivelines will work. So will your rear end and radiator (both are insufficient for a V8 swap). The hookup between the Chevy headers and Jeep exhaust is easy as well. I went with full rebuilds on the engine and tranny, so my project wasn't cheap (see my build thread in the other forum), but if you can find a decent running S10 and just swap it all in without touching it, that would be relatively inexpensive. Of course, those Bazers are all pretty long in the tooth too, so finding one that's good to go might be a challenge. You could also get the T-case and 700R4 from a Blazer, and put just about any GM engine you want in front of it (some would take adaptors). But that's the other plus with this particular swap: Once it's done a V8 upgrade is a bolt-in replacement for the 4.3 later if you want more power.

My 4.3 YJ is a lot of fun. It's spunky, but not excessively powered for a rig with so short a wheelbase. The 4th gear in the automatic means cruising at freeway speeds is not a problem. Honestly, you'd very likely get better mileage from a 5.3 LS engine, though. Those things are amazing, and worth looking at if you're considering a swap even if they're more work and expense.
 
Not knocking Walts suggestions, but its been my experiences to go rebuilt. I think finding a decent 258 will be tough. Second find out why the OE engine cooked. bad radiator or and address that. Id buy a quality long block ,no CHINA JUNK parts, or rebuild yours if there is a good rebuilder in your neck of the woods who will use quality bearings,cam,pistons etc,etc. There is nothing worst than doing all the work of swapping an unknown used something only to find out its junk. A warranty is great provided your willing to pull that ran like new "used engine" and start over again whilst hoping to get your money back for the first go around of junk.
 
Thanks to both of y'all for the advice!

At this point, I think we'll just go with the rebuild. As appealing as Walt's swap ideas are, we have a decent rebuilder in our town, and I honestly just don't have the time and need a running vehicle. Thanks Again!
 
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