85 XJ Engine Swap

From what i have heard it can be a real pain in the butt to swap a bigger engine in to my 85 XJ.. I have also heard that the 3.9 or 4.3 chevy engines would work.. Any experience with this or suggestions?

What engine do you have in there now? a 3.4 swap is the best way to go. NOt the 3400 series engine but the 3.4.

Your current trans has the 60deg GM V6 belhousing on it. A 4.3L will not bolt up. Like the previous poster said, the 3.4L is the largest common one that will fit.

If you can find a 3.8L EFI engine made for a RWD application it will work, but they are not real common.

Yep, the easiest swap is getting a 3.4 from a mid 90's camaro/firebird. DO NOT buy the block from a front wheel drive car, the engine mounts are cast differently for some models.

Please do a search using "vortec", "2.8 swap", 3.4L swap, etc..... you'll find lots of threads on the subject, this gets discussed very often.

Don't pass up the FWD donors out of hand, tho. Many of them wound up with "Goodwrench Service Replacement" engines, and those have starter mounting bosses on BOTH sides, so they could be used in FWD and RWD/4WD vehicles.

To check, crawl under and look at the REAR side of the block, as mounted. If there is a mount pad for the starter back there (shouldn't have anything bolted to it, tho...) you've found a GSR engine, and can go ahead and pull it out.

Of course, if you find an S-series or an F-body (Camaro/Firebird) with a 3.4V6-60 in, you'll be able to use that anyhow. However, I am inclined to think that the GSR engines may have had slightly thicker castings, which gives you more room for machine work as well.

You should be able to find more information as well on the various F-body and S-series enthusiast boards, and check www.60degreev6.com (?) as well...

5-90

If you are running the 2.5L, the swap to 4.0L won't be that much different than the other swaps. I did it. The key is to find a donor vehicle to strip the parts from since the engine, tranny, and tcase should be swapped together for compatibility. You also need a hood, front sheetmetal, wiring harness and computer.

Hi:
I was advised that if you're going thru all the expense and labor for the Chevy V-6 cylinder 3.4 liter or 4.3 liter on your tired out XJ then you might consider the ole" tried and true"( non-fuel injected for ease of installation and simplicity )Chevy 350 V-8 carbureted engine for almost triple the horsepower-I did-There is a wealth of technical and mechanical information here at in the archives as well as the pros and cons of these engine swaps for you to be able to make an informed decision-As alway do a search and see what other members have done-HTH
















asHTH

First off he is listed as having a pre 87 and the 4.0 would not go in easily. The 3.4 is a direct replacement for the 2.8. So he would only have to get the wirieing for the FI to work on the FI ones. Someone on here did the swap with FI. They listed a company that builds a bolt in harness for that motor for the xj.

The fire wall would have to be cut in order to put in a 4.0. As for the 350 v8 You would have to have a wiring harness a different transmission or maybe a Novak Adapter http://www.novak-adapt.com/ but they arnt cheap! I looked into putting a SBC into mine and it was going to cost more than a heavily modified 2001 XJ by the time I got done. You could find a MOPAR TF904/909 and Put that in place of your TC904/909 with the GM small corprate bolt pattern. Then with the MOPAR Tf904 you could put in up to a 383. if you go that route I would put in an A500 it has a 4th gear in it for overdrive!

1985xjlaredo said:

The fire wall would have to be cut in order to put in a 4.0. As for the 350 v8 You would have to have a wiring harness a different transmission or maybe a Novak Adapter http://www.novak-adapt.com/ but they arnt cheap! I looked into putting a SBC into mine and it was going to cost more than a heavily modified 2001 XJ by the time I got done. You could find a MOPAR TF904/909 and Put that in place of your TC904/909 with the GM small corprate bolt pattern. Then with the MOPAR Tf904 you could put in up to a 383. if you go that route I would put in an A500 it has a 4th gear in it for overdrive!

Click to expand...

..I repeat-All model years of the XJ has the same interior and exterior dimensions-You DO NOT.. have to cut/modify the firewall,..you're going the wrong way..- the FRONT of the pre-inline six radiator placement is cut/modified instead-This is where the additional engine compartment room is found if you need to do this swap-I don't to want to oversimplify the conversion but Chevrolet 350 V-8's with 700R-4 are relatively CHEAP, PLENTIFUL and very ABUNDANT in virtually every boneyard in the world-Check out the sage information given out over at Advanced Adapters and again I and many others have done the Chevy 350 V-8 700R-4 on my 1984 XJ-It is a sound and good cost-efficent way to increase the horsepower(..triple from 2.5 liter or 2.8 liters..)-Again do a search before posting erroneous or misleading information-

SPOBI
You're dead wrong.
the firewall was changed in 87 to accomodate the 4.0's length
The front clip and radiator mounts were changed, and the hood latches were relocated to the sides in order to make room for the now pushed farther radiator.

I have done the 2,5L to 4.0L swap on an 85 so I'm not talking theory, I'm talking fact.

The firewall is different but not by much. It can be modified in about 2 minutes with a bfh. There is nothing behind it in the way. You need to depress a protruding corner about a half inch. The bigger sheetmetal issue is the front metal crossmember behind the facia, and swapping the hood. This means cutting and moving the front brace. Done right, no welding is needed.

I have a few years of body work experience. It is a simple mod but you have to score the parts first. The nice thing is if you stay with the 4.0L, you can score the parts easily and when you get done, you have a vehicle that can be maintained and is the same as the newer models. When I did the swap, I actually put in a 4.7L stroker instead of the stock 4.0L. Boy what a change.

well that clears it up.
The firewall is different, but easily modded.

Honestly though, unless the rig he has is immaculate or super special in some way you will be way farther ahead to sell it and buy 4.0L XJ ready to go. You can pick up fairly nice RENIX rigs around here for right around $1500 easy anymore, beat up ones are even cheaper.

On the chevy 350: the TBI engines are easy to wire if you have knowlege of the sensors and such you can reuse the stock harness, or spend $300 on a Howe or painless one.
Run a TH700 or similar trans with a NV241 from an IFS pickup to get drivers drop and fab up all needed mounts.
I would personally rather have a 4.0L but everybody has their reasons.