Motor swap

[madog7200]

I'm swapping the motor on my 91 6 cylinder, and I'm wanting to know how new of a motor will line up and fit or if I have to have a 91? Thanks in advance

 

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[87Chief]

Are you wanting another 4.0L or something else? I think up to 96 fit just the sensors are different, not sure which ones though.

[Pete M]

what went wrong with the current motor?

[Eagle]

In terms of physical fit and lining up, any 4.0L will fit -- up to a 2001 Choerokee or whatever year Wrangler or Grand Cherokee still had the 4.0L engine.

 

Sensors and fuel injection aren't all the same, though.

[johnj92131]

There are some differences in the late Grand Cherokee blocks in where motor mounts attach that mean those blocks do not bolt in to the Cherokee or Comanche.

 

There is a very complete article Don posted a link to several years back that lists a very complete list of casting number changes for the life of the 4.0.  I thought I bookmarked it but did not find it with a quick search.  Perhaps Don will repost the link?

[MeanLemons]

1987-2001 XJ blocks interchange
1987-1992 MJ blocks interchange
1990-1995 YJ blocks interchange
1993-1998 ZJ blocks interchange
1997-1999 TJ blocks interchange

2000-2006 TJ blocks do not interchange
1999-2004 WJ blocks do not interchange

[HOrnbrod]

http://www.enginebuildermag.com/2006/05/peras-core-corner-its-time-to-say-goodbye-to-an-old-friend/

[johnj92131]

Thanks Don.  I bookmarked it this time for sure.  May I also suggest it should be a sticky in the DIY section (if it is not already).

[HOrnbrod]

Thanks Don.  I bookmarked it this time for sure.  May I also suggest it should be a sticky in the DIY section (if it is not already).

 

Good idea - I'll take care of it. :cheers:

[madog7200]

Wanting another 4.0 HO... nothing really went wrong but there was a lot of blow by and we were trying to replace the rear main but the PO sprayed some sort of adhesive to hold it in place so we were going to have to drop the crank... which led us to decide to pull the motor and rebuild it...

 

After the motor was pulled and some research was done we decided that it would be more cost efficient to buy a reman with a warranty rather than rebuild and have no warranty

 

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