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Unread 10-27-2013, 04:23 PM   #1
Bergy1
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4 cyl engine compatibility ?

Will a cj 4 cylinder out of an 84 or an 86 work with a yj(90) 4 cylinder? I have a friend with a 90 that has a bad bottom. I have access to a 4 out of a cj with good parts. Can these be mixed up for parts?

Thanks

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Unread 10-27-2013, 04:31 PM   #2
jokerchief462
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You have to look closely at engine mount bracket holes and the front if the block for accessories. They have been the same basic block for years.

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Unread 10-27-2013, 04:42 PM   #3
ddferdt
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Don't some states frown upon older engines in newer cars?
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Unread 10-27-2013, 04:55 PM   #4
jokerchief462
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Oh yes but I have no idea which ones other than CA which has a law for everything.

If you use the basic block and bolt all the old stuff on to include the emissions stuff how are they going to know other than chasing down a casting number.

The jaw keeps folks from getting around the emissions equipment for the model year if the vehicle.

With that said if all is still installed at the finish what's the problem. None that I can see.

So you use the stepped long block and bolt all the 1990 stuff back on. Nothing to mess with in wiring or ecu and should be legal and pass any inspection.

The block doesn't know any different it only does what it's told.

The biggest problem is mount homes with the different casting series.

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Unread 10-27-2013, 05:28 PM   #5
Bergy1
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Our state doesn't do emission testing, block checking, smog checking, or any other green peace checking:-)
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Unread 10-27-2013, 05:30 PM   #6
ddferdt
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Quote:
Originally Posted by Bergy1
Our state doesn't do emission testing, block checking, smog checking, or any other green peace checking:-)
Lucky you, bought mine with the cat deleted and it won't pass inspection unless I put one on -_-
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Unread 10-27-2013, 05:32 PM   #7
ashland82391
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This seems like a huge down grade. Won't you be going from fuel injected to a carburetor?
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Unread 10-27-2013, 05:41 PM   #8
jokerchief462
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The compatible part you are looking for is the bare long block. No downgrade. Strip it and bolt all the original equipment back on. An engine block doesn't know the difference.

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Unread 10-27-2013, 06:03 PM   #9
Bergy1
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Jokerchief, that's the info I was needing. Thanks!
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Unread 10-28-2013, 10:47 AM   #10
Que89YJ
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The 84 was the first year of the AMC 2.5L. You need to make sure that it is no earlier then 84. The GM Iron Duke was used in the CJ before 84 and it will not bolt up without some work.
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Unread 10-29-2013, 07:54 AM   #11
Bergy1
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K. I will check on that
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Unread 10-29-2013, 08:40 AM   #12
schaef89
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I just recently found out that my 89 has a 2.5 from a 85 in it after I looked up the casting number. All my TBI stuff fits and I wouldn't have known the difference if I didn't look it up
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Unread 10-29-2013, 05:15 PM   #13
Bergy1
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It's out of an 80, so I guess my friend is back to looking for another engine.
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Unread 10-30-2013, 07:57 AM   #14
Que89YJ
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The 80 would be the gm engine. There are a lot of 2.5 engines out there.
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