So uhhhh Cylinder #5 huh.

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Aug 8, 2021 | 02:58 AM
  #1  

Engine blew up a month ago and started taking her apart to see what happened. Think she's recoverable? Broken piston skirt obviously but she's my only vehicle and I'm broke broke so can't afford anyone else to do it. Not too many pick and pulls around me either and half of them are closed whenever they want.
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Aug 8, 2021 | 04:07 AM
  #2  
You would have to check the block for cracks and for being out of round. Step one is to find a friend with the needed micrometers for measuring your bores. Instead, I would get a different engine to put in. If it was a '34 Packard I would look at rebuilding the engine, a Jeep 4.0 not so much.
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Aug 8, 2021 | 09:42 AM
  #3  
Yeah that looks bad. You'd have to pull the piston and examine/measure the cylinder. There's a chance you can just replace the piston and rod if you can clean up the cylinder enough. I had a similar issue on a 95 YJ 2.5l where I believe the wrist pin seized. I was honed the crap out of the bore and dropped a new piston and rod in. I sold it 30k miles later with still running strong. Interestingly, about half the rings were installed upside down with the bevels facing the wrong way from the factory.

Another thing to consider is that this is a 2000 with the 0331 heads that were prone to cracking. If the bore looks bad, I'd shop around for a good used engine instead of dumping money into that one.
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Aug 8, 2021 | 07:20 PM
  #4  
Quote: Yeah that looks bad. You'd have to pull the piston and examine/measure the cylinder. There's a chance you can just replace the piston and rod if you can clean up the cylinder enough. I had a similar issue on a 95 YJ 2.5l where I believe the wrist pin seized. I was honed the crap out of the bore and dropped a new piston and rod in. I sold it 30k miles later with still running strong. Interestingly, about half the rings were installed upside down with the bevels facing the wrong way from the factory.

Another thing to consider is that this is a 2000 with the 0331 heads that were prone to cracking. If the bore looks bad, I'd shop around for a good used engine instead of dumping money into that one.
my 0331 actually looks perfect aside from needing to be cleaned up a bit. this happened after i had to race to a family emergency and tried to drive back to work. ran strong on my way there and blew on my way back
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Aug 8, 2021 | 07:23 PM
  #5  
Quote: You would have to check the block for cracks and for being out of round. Step one is to find a friend with the needed micrometers for measuring your bores. Instead, I would get a different engine to put in. If it was a '34 Packard I would look at rebuilding the engine, a Jeep 4.0 not so much.
being in alaska there’s not exactly a surplus of short blocks around and what not that’s why i’d prefer to rebuild it but i’ll have to see what kind of damage is done. i’ve got the tools to clean it up and what not.
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Aug 8, 2021 | 11:15 PM
  #6  
pull out the broken piston and then take another piston and put it in # 5 and see how good it fits and see if it moves side to side or if it rocks .
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Aug 9, 2021 | 05:27 AM
  #7  
Quote: my 0331 actually looks perfect aside from needing to be cleaned up a bit.
Yeah.

Today.

Use https://www.car-part.com/ to see what engines are available. There's 2 direct fit and a bunch of others if you want to go pre-2000.
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Aug 9, 2021 | 05:33 AM
  #8  
Quote: Broken piston skirt obviously ...
2, actually.

Which begs the question, what did the rod do while this was happening? Or did the rod go first?
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Aug 9, 2021 | 06:18 PM
  #9  
Its going to need to be bored for sure. No way around that with that kind of exploding piston. I can guarantee you it will need to go at least .030" over.
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Aug 9, 2021 | 10:20 PM
  #10  
Quote: Its going to need to be bored for sure. No way around that with that kind of exploding piston. I can guarantee you it will need to go at least .030" over.
nah rebuilding the 4.0 isn't too expensive and relatively easy not dealing with a V, I've seen how much my buddy's dirt car is though, hell no haha
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Aug 10, 2021 | 10:02 AM
  #11  
Quote: nah rebuilding the 4.0 isn't too expensive
Quote: I'm broke broke
I guess "expensive" is relative.

Especially if you're double-broke.
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Aug 10, 2021 | 12:54 PM
  #12  
Quote: nah rebuilding the 4.0 isn't too expensive and relatively easy not dealing with a V, I've seen how much my buddy's dirt car is though, hell no haha
It sounds like you havent dealt with these 4.0s before.... They are cheap to rebuild but I am putting money on it that you need to bore the block. Well at least if you want to do things the right way. No I take that back. It just needs to be bored.
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Aug 10, 2021 | 04:33 PM
  #13  
If one skirt broke, best check them all. Tear it down. Block, rods, everything.
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