1985 Cherokee 2.8 V-6 4 Door Auto, Engine Tips

Does anybody have any helpful hints on modifying the 2.8 v6 for better performance, and also any specs on axels or gear ratio's that I might need?

yeah, get rid of it. get a 3.4 from a camaro. bolts right in.
gear ratio could be 3.07 to 4.10.

trans type? auto/manual?

Its an auto. Would I pull the tranny with the 3.4 also? what about a 4.0? How easy is that.

4.0L would be hard different everything pretty much. You could build it up thats what I did and its ok now. a 3.4 would be your best bet but it is a little more than just bolting it in. Check out 60degreev6.com there is a lot of good advice on there for the 60 degree chevy engines on there.

Olympia said:

Does anybody have any helpful hints on modifying the 2.8 v6 for better performance, and also any specs on axels or gear ratio's that I might need?

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I have a 85 w/ a 2.8 that had a full rebuild with mild rv cam. Rebuild has less than 15,000 Miles before Jeep was smacked. After rebuild it had substancially more balls than stock and got over 20 mpg on highway. Its in my backyard and I would love for it to have a new home. I am in Lakewood,..just up the road. Price would be "right". PM me if interested. Also has 3" lift.

Thanks everybody it looks like for now I will just put some add on's and stuff, but hopefully I will be able to put a 3.4 in.

Put in a 3.4 V6. I bought a new one from Scoggin-Dickey for about 1800.

Simple and easy swap.

One piece of advice: Get the tranny beefed up. When I put mine in, The tranny burned out due to the extra torque. Also, beef up the NP207 that's under there or swap it with a NP231.

Other mods: you need to install an electric fuel pump, get a better carb (a Weber 38 DGES fits on the manifold) and add gauges while you're at it.

Any ???s then you can PM me.

You will notice more power and torque.

if you want to swap it out for a 4.0l then find a doner and take motor and tranny, cross member and drive lines everything should bolt right in. If you just want more power then go through your 2.8 and stroke it to a 3.1 A.R.I. has a 3.1l kit for less than $600 put a big cam in it large valve heads and rejet the carb.I am doing mine and so far im under $1000 bucks into it. Or you can get the direct replacement 3.4l wich has less power than what i was saying to do for nearly a$1000 more good luck

pabloconrad said:

Put in a 3.4 V6. I bought a new one from Scoggin-Dickey for about 1800.

Simple and easy swap.

One piece of advice: Get the tranny beefed up. When I put mine in, The tranny burned out due to the extra torque. Also, beef up the NP207 that's under there or swap it with a NP231.

Other mods: you need to install an electric fuel pump, get a better carb (a Weber 38 DGES fits on the manifold) and add gauges while you're at it.

Any ???s then you can PM me.

You will notice more power and torque.

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Something had to have been wrong with your tranny Chrysler was putting them behind all kinds of V8's in the 60's and 70's
Your best bet if you are going to spend 1800.00 plus is to drop in a 350sb. THey have them at the local dealer here for 1649.00 ready to run. Chevy Has tons of these engines (literally millions of them) and they are cheap right now because of it. Throw a Later TH700 behind that with a Dana 300 and for about 2200.00 You will have one badass 85 XJ. That's what I wish I would have done. Instead I polished the turd that was under the hood and i'm still kicking myself for it.

sounds like i got options, thanks guys

4.0 wouldn't be worth it as the engine bay is smaller and you are going to have to do some modifying. also you would have to buy a transmission as well bringing in a higher cost. The 3.4 could be found for a couple hundred dollars if you look around and it will bolt in easily with few modifications. Don't waste your money hopping up the 2.8. not really worth it. heck, my 2.5 4 cyl has more power than that AND its fuel injected. that would bolt right in as well. The tf904 even has the CPS slot already in it. the electronics would have to be worked out though.

i know this is stupid but what is a cps, is that something to do with the computer?

CPS is the Crank Position Sensor...it is basically an electronic pickup mounted on the transmission bell housing...it detects the rotational position of the engine/crankshaft via the position of the flywheel/flexplate and feeds that info to the computer , so that the computer will know when to spark the plugs, etc.

man, i got alot to learn

Olympia said:

man, i got alot to learn

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Grab some books and start reading. Ask tons of questions and you'll be OK.

1985xjlaredo said:

Something had to have been wrong with your tranny Chrysler was putting them behind all kinds of V8's in the 60's and 70's
Your best bet if you are going to spend 1800.00 plus is to drop in a 350sb. THey have them at the local dealer here for 1649.00 ready to run. Chevy Has tons of these engines (literally millions of them) and they are cheap right now because of it. Throw a Later TH700 behind that with a Dana 300 and for about 2200.00 You will have one badass 85 XJ. That's what I wish I would have done. Instead I polished the turd that was under the hood and i'm still kicking myself for it.

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I believe my transmission wasn't taken care of by the previous owner. It had 150K on it when I bought the Jeep in 99. I too wish I would've put in a better engine/tranny/t-case combo. But once that starts, then the driveshafts, axels, wheels, etc.

Hey, I'm running a 3 spd auto on my 2.8L and I have been looking at moving over to a stick. I've heard rumour that you can jam a Borg-Warner T-5 5-speed in there.

I'm just wondering if this is true. As much as I love Wiki I'd like to be sure before I get into this.

Olympia said:

Does anybody have any helpful hints on modifying the 2.8 v6 for better performance, and also any specs on axels or gear ratio's that I might need?

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Search web for 2.8L hop up parts.
Not really worth it. The big trick on the 2.8L is getting it in it's power band and keeping it there. That is 3000-4500rpms. Stock axles are about the same as a 2.5L. 3.73 for the manual, 4.10 for the auto.

When I had my 86" I put on 31's, and eventually swapped in 4.55s. The thing perked right up with the lower gears.

Yes, GM makes a crate motor for a 2.8L upgrade. Check the GM Performance website.
You will need to make your flywheel or torque converter balance with the new engine by cutting off the weights which are there now. Some GM motors did not come with a fuel pump boss, and you will need to supply an external fuel pump.

As for the 4.0L drivetrain swap. More effort than it is worth.
A nice (7 out of 10) used XJ with a 4.0L already in it sells between $1200 and $3000.

Unless this truck has a pristene exterior, whole floors and frame, you may want to consider a newer XJ with a HO, or late model drivetrain. Wouldn't want to see you put losts of time and money into something you will be getting rid of in a year or two anyway.

Enjoy your rig for what it is. Make changes you can swap over to a newer rig when you decide to upgrade.