Hello My name is Shawn and I'm looking for info on my jeep. It's a 1985 Jeep cherokee Pioneer 4X4 5 speed manual. It's got a 2.8L V-6 and I was wondering if anyone has ever put a 3.4L in one and wanted to know how hard it would be to do so. If it's going to be a problem to do that I was wondering what other options I had, the problem I'm haveing is that the enguin is knowcking and oil preasure is way low. When I rev the enguin then knocking stopps and the oil preasure go to almost normal. My jeep has 163,000 miles and Changed the oil several times and I've pulled the valve covers off to see if it may have been a rod or something and everything up top was normal, no dammage. Now I'm totaly confused as to what it could be. I dont have a lot of background working on jeeps so I would welcome any advice on this topic. Thanks
2.8 to a 4.0
- Thread starter shawn
- Start date
mingez
New member
Have you already purchased your 4.0?
I'm pretty sure it does not. I've read up on this a bit when I was looking for an XJ, and this swap is rarely done. If you shoehorn a 4.0 into it, you'll have to mess with your firewalls bellhousing, and I don't think that transmission will mate.
Everything I've read is that the Chevy3.4 is the best swap for that motor. Bolts right in with a few mods, and the stock transmission fits as well (if it's a 904).
The 2.8(and 904) are for the Chavy 60 degree V engines which also includes the 3.1, 3.4 motors.
Also, I hear the 3.4 with the right cam and it being a light engine, is quite comparable to the 4.0. Just slightly less torque at certain RPMs, and a bit less HP.
Endeavoring to put a 4.0 in that Jeep is a pretty daunting project. Don't forget about issues with your Tcase, gearbox, electrical, radiator etc. I wouldn't be able to do it that's for sure.
Perhaps Nick, balloo or some of the other more tech-savvy XJ guys would know.
I'm pretty sure it does not. I've read up on this a bit when I was looking for an XJ, and this swap is rarely done. If you shoehorn a 4.0 into it, you'll have to mess with your firewalls bellhousing, and I don't think that transmission will mate.
Everything I've read is that the Chevy3.4 is the best swap for that motor. Bolts right in with a few mods, and the stock transmission fits as well (if it's a 904).
The 2.8(and 904) are for the Chavy 60 degree V engines which also includes the 3.1, 3.4 motors.
Also, I hear the 3.4 with the right cam and it being a light engine, is quite comparable to the 4.0. Just slightly less torque at certain RPMs, and a bit less HP.
Endeavoring to put a 4.0 in that Jeep is a pretty daunting project. Don't forget about issues with your Tcase, gearbox, electrical, radiator etc. I wouldn't be able to do it that's for sure.
Perhaps Nick, balloo or some of the other more tech-savvy XJ guys would know.
mingez
New member
Okay, I read your other post before this one. Yes the 3.4L is the easier swap.
You can get this engine from a 93-95 camaro/ firebird and I believe there is a crate motor for that application as well.
To make it work, it's best to use the Cherokee intake and exhaust manifolds. The 2.8 uses a mechanical fuel pump mounted on the engine. The 3.4L doesn't. If you stay with a carb, you'll have to install an electric fuel pump. That's not a big deal either. So from reading up on it, it seems like a relatively simple swap.
This is all theory and no practice, so keep researching. When I was searching for a cherokee, and almost bought one with a 2.8, and saved all of my research on the difficulties of modifying those engines.
You can get this engine from a 93-95 camaro/ firebird and I believe there is a crate motor for that application as well.
To make it work, it's best to use the Cherokee intake and exhaust manifolds. The 2.8 uses a mechanical fuel pump mounted on the engine. The 3.4L doesn't. If you stay with a carb, you'll have to install an electric fuel pump. That's not a big deal either. So from reading up on it, it seems like a relatively simple swap.
This is all theory and no practice, so keep researching. When I was searching for a cherokee, and almost bought one with a 2.8, and saved all of my research on the difficulties of modifying those engines.
Bounty__Hunter
Super Moderator
Go with the 3.4L, less hassle. GM performance makes a crate 3.4L they say is a direct bolt-in for the terrible 2.8L engine, which leads me to believe there are a lot more issues using an OEM 3.4L out of another vehicle.
I'd check some GM boards or contact GM performance and find out the advantages of going with the crate 3.4L over one from a donor vehicle.
The 4.0L will take a lot of work, probaby have to beat on the firewall and install a new grille support for the longer engine.
I'd check some GM boards or contact GM performance and find out the advantages of going with the crate 3.4L over one from a donor vehicle.
The 4.0L will take a lot of work, probaby have to beat on the firewall and install a new grille support for the longer engine.
the 4.0 will not fit in the engine compartments of the 2.8 liter cherokees. They lengthened the engine compartment in subsquint years to accomodate the length. You have to beat the firewall back to get it to fit. also 2.8l is a GM motor and although the 904 is a Chrysler transmission its bolt pattern to fit GM motor. The 3.1 or 3.4 is the best sollution.
I had the same type of knock on a 84 cherokee. Sound horrible at a idle then would go away as I accellerate. Turned out the flexplate was broken in two. It had broken in a jagged fashion so it still was drivable but made a horrible noise at idle. I was given the cherokee from somebody who thought it was a rod. I drove it home replaced the flexplate and drove it for a few years.
I had the same type of knock on a 84 cherokee. Sound horrible at a idle then would go away as I accellerate. Turned out the flexplate was broken in two. It had broken in a jagged fashion so it still was drivable but made a horrible noise at idle. I was given the cherokee from somebody who thought it was a rod. I drove it home replaced the flexplate and drove it for a few years.
Similar threads
