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  #1  
Old February 6th, 2006, 00:10
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geepxj geepxj is offline
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2.8 to 4.0 swap questions?

So I am planning on putting a 4.0 w/ Aw4 and np231 out of a 90 xj into my 87 pioneer that runs the 2.8 V6. I did some searching on the forum and saw that the one thing that bacame a problem when doing this swap was that the firewall would get into the way with the 4.0 and doing a 3.7 would be a better idea. I was wondering if anyone has done the 2.8 to the 4.0 swap and has any pics or good advice to take care of the problem that comes up with the firewall. I already have the 4.0 and I dont have the money to spend on a 3.7. thanks for any info, pics and feedback.
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Old February 6th, 2006, 04:00
75SV1 75SV1 is offline
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Re: 2.8 to 4.0 swap questions?

You need to look at the post you are getting your info from. Yours is an '87. The '87 had the 4.0 as an option, so the front end is a bit longer. If the post you are getting your info from is an '86, then you would have major work. You will need to get the wiring, sensors, fuel pump, ECM, distributor, flywheel/flexplate from the year you are swapping in. The '90 should be a Renix motor.
Tom
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Old February 6th, 2006, 09:02
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5-90 5-90 is offline
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Re: 2.8 to 4.0 swap questions?

You might also find it easier to swap in the AMC 4 cylinder (perfectly acceptable, already an option for you, and a better engine!) or look into the idea of a SBChevvy swap.

The inline six is do-able, but will take loads of work - as has been mentioned, the front clip was redesigned - lengthened - in 1987 to accommodate the 4.0.

Since you're here in the Bay Area, you're also going to run headfirst into Smog - you'll have to get Referee approval for the 4.0 swap. The 2.46 was an option for your year - which will make it easier - and getting a RWD 3.1 or 3.4 will make it possible to "camouflage" your engine swap, thereby avoiding most of the Smog issues (if you get fuel injection vice your carburettor, it should still be easier than switching plants entirely to the 4.0 - you can ask about, and tell them, you're just swapping in fuel injection. outside dims on the 2.8, 3.1, and 3.4 are all the same.)

Candidates for donors include the F-body and S-10/S-15 series vehicles.

5-90
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Old February 6th, 2006, 09:12
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geepxj geepxj is offline
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Re: 2.8 to 4.0 swap questions?

cool thanks for the heads up, I am glad I asked before I dove right in.
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Old February 6th, 2006, 09:30
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Re: 2.8 to 4.0 swap questions?

Quote:
Originally Posted by 75SV1
You need to look at the post you are getting your info from. Yours is an '87. The '87 had the 4.0 as an option, so the front end is a bit longer. If the post you are getting your info from is an '86, then you would have major work. You will need to get the wiring, sensors, fuel pump, ECM, distributor, flywheel/flexplate from the year you are swapping in. The '90 should be a Renix motor.
Tom
I unfortuannly misread what I had, I looked at the inside of the door and I have an 86. So I am going to have to figure out what needs to be done, As for the ecm, flywheel, fuel pumpsensors and so on. I was actually planning on swaping out the whole drivetrain from the 86(motor,tranny,Tcase) and putting the whole drive train of the 4.0 in. (motor,tranny,tcase)
I am sorry to go over this again, but it was also listed that 87s were lengthend for the 4.0, know does that mean a 4.0 wont fit in a 86 due to size or I will have to cut the fire wall? And if I do have to cut into the firewall has anyone done this that can give me a heads up on what to watch out for. I just want to make sure I dont start cutting things that end up srewing me over. Once again thanks for all help, suggestion, and comments.
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Old February 6th, 2006, 09:49
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Re: 2.8 to 4.0 swap questions?

The firewall is just one issue, it's still to long up front from the motor mounts foward.
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Old February 6th, 2006, 09:57
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87manche 87manche is offline
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Re: 2.8 to 4.0 swap questions?

you would need a new front clip, and a new hood. The hood had the latches moved to the corner in 87 I believe to accomodate the 4.0's length. You would also have to put new engine mounts in. You sould read this:
http://www.lunghd.com/Tech_Articles/...Project_XJ.htm
A good write up on replacing your 2.8 with a 3.4 Pretty much as "bolt in" as you're going to get short of another 2.8
I had found another page that detailed how to keep the 3.4s injection, but I don't have my bookmarks at work. Google is your friend.
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RIP Ugly Truck
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Old May 22nd, 2006, 19:05
xjpio xjpio is offline
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Re: 2.8 to 4.0 swap questions?

For peoples info there is the following site with some info on doing a 2.8L to 4.0L engine swap:

http://members.shaw.ca/Jeep.XJ/content/engine/prep.htm
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