'90 4.0 to replace '87 4.0..?

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xjwoody

NAXJA Forum User

Location

Suburban Philadelphia

• Jan 6, 2004

• #1

I found a 1990 4.0... will it swap easily..? Into my 1987 XJ Wagoneer..

 

X

xjwoody

NAXJA Forum User

Location

Suburban Philadelphia

• Jan 6, 2004

• #2

btt..

 

ACE

NAXJA Forum User

Location

N. Utah

• Jan 6, 2004

• #3

An '87 and a '90 4.0 will swap easily with no modifications. The big change was in '91.

 

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desertred

NAXJA Forum User

Location

Along the Wet Mountains, CO

• Jan 7, 2004

• #4

Is 91 when the HO motor was introduced? What type of modifications are needed to drop a HO 4.0 into an earlier XJ?

 

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tlman

NAXJA Member #20

Location

Arlington, VA

• Jan 7, 2004

• #5

Physically they will bolt right in but the computer and wiring harness were changed when the HO engine was introduced so you need to transplant the entire package and mate it up to the existing chasis.

 

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tys

NAXJA Forum User

Location

NY

• Jan 7, 2004

• #6

tlman said:

Physically they will bolt right in but the computer and wiring harness were changed when the HO engine was introduced so you need to transplant the entire package and mate it up to the existing chasis.

Click to expand...

Not entirely true...I swapped in a 96HO XJ motor into a YJ using an 87 XJ Harness. I used the HO intake manifold and had a machine shop mill me an aluminum throttle body adapter so I can use the 87 throttle body on the 96 intake.

Chris

 

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tlman

NAXJA Member #20

Location

Arlington, VA

• Jan 7, 2004

• #7

I agree that you can go that way too but you may have trouble getting it through a smog check if you reverse engineer the engine management system.

 

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xjwoody

NAXJA Forum User

Location

Suburban Philadelphia

• Jan 7, 2004

• #8

Well... I found a 1990 with 150K for almost nothing. My 1987 runs fine with less than 150K. I figured I could rebuild the 1990 4.0 for a few years, then toss her in when she's ready. You know, take my time.. Do it right.

I am still considering it.

 

CheapXJ

NAXJA Forum User

Location

570, 813 or 303

• Jan 7, 2004

• #9

if it ain't broke don't fix it.

that Jeep will rot away before you have ANY kind of engine trouble

 

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xjwoody

NAXJA Forum User

Location

Suburban Philadelphia

• Jan 7, 2004

• #10

Well.. I do have some nasty sounds coming from inside there.. Sounds like wasted lifter(s).. Not to mention some substantial blow-by, despite vacuum line changes, etc. And a few oil leaks.

I appreciate your zeal, but I haven't the same confidence as y'all..

It would be a long term project, anyhow..