StormTrooper4x4

Okay so I have a Jeep Comanche project I am currently working on and I'm in the process of taking out the eningie to take out and replace my current crankshaft, I'm also looking for other options for a new engine because I am aware that the GM 2.6l V6 is one of the weakest engines they put into the Comanches, I also know that due to the changes in firewall and probably others I dont know about I am unable to put a 4.0 I6 in without major modifications, so what im getting to is are there any engines that I can put in without huge modifications on my part?

Gee oh Dee

I moved this to Modified Tech since the Build sectikn is more geared for documenting ongoing builds.

As for your question, I want to say a 3.1 or somethibg like that fits, but I could be wrong.

noXaddtheM

Im in the same.boat you are. I have an 86 comanche longbed with the 2.8v6. Mines not bad because i only have 126k miles on it.

As for swaps, ive done a ton of research, and your best best for a "bolt in" engine, is the 3.4 out of a v6 firebird. You end up using some 2.8 parts on the 3.4. There are writeups online for the swap, keeping it carbed or going the fuel injected route. The 3.4 is basicly an upgraded 2.8, so from what i gather, you can keep your stock trans and all.

Ill look for the site that gave me most of my info and put it up here for you. Goodluck, hope this helps.

noXaddtheM

http://www.lunghd.com/Tech_Articles/...Project_XJ.htm

Here you go, he kept his carbed.

http://www.s10extremist.org/tech_art...28to34swap.htm

Not a xj, but good info.

Id say read as much as you can from these sites. Its a pretty straight forward swap, from what i see. And ive done alot of honda swaps and older v8 swaps, hell, even a v8 focus swap, so i know a thing or two and how simple this looks (in theory). But youll always have hiccups, so if youre gonna do it, READ, READ, READ.

freegdr

Theres a very detailed write up here about it ...http://www.lunghd.com/Tech_Articles/...Project_XJ.htm

noXaddtheM

Thats the first link i put, lol.

ExTrEmExJ99

I had a 86 comanche and the motor was shot. I then picked up a 99 xj for a donor to swap everything over ( motor, tranny, tcase, axles, interior, doors and front clip) everything will swap they say late 86's have the correct firewall. I was going to put in the 3.4L but gm had problems with all the 60 degree v6s. Put in a 4.0L buy a donor xj and swap everything over. You will be more happy. Oh I sold the comanche and started building the xj

StormTrooper4x4

Thanks everyone for all the great input this will help a lot!! I've heard about the firebird swap and have done alittle research but for now I think I might stick with the 2.6l for awhile until I get it built up! Again thanks for the help!

5-90

RWD/4WD V6-3.1L or 3.4L, but make sure to grab electronics from the donor (since you're also moving toward fuel injection.)

Ideally, grab the entire drivetrain out of an S10/S15, since that is likely to net you the THM700R4/4L60 transmission (stronger trans, with overdrive, than the A904) and the NP231C transfer case (1.25" drive chain, vice the 1.00" drive chain in the NP231J.) You'll probably have to adapt the transmission mount and have driveshafts made, but the presence of the overdrive gear should help recover that cost (at $4/gallon!)

Avoid the THM400 prior to 1987 - but later versions are fine.

The V6-3.1L and 3.4L are based off of the same castings, but are far better engines than the 2.8L and don't leak like the 2.8L does. As I recall, the 3.1L is a bored 2.8L, and the 3.4L is a 2.8L bored & stroked.

Information on the engine family can be found at www.60degreev6.com, as I recall - it's a forum dedicated to the GM V6-60 family (may be .org, I'm not sure.)