engine swap?

[zzze]

what engine or engines can cheaply and easily swap into an mj and make it faster while keeping a near normal gas mileage? (17 mpg)

[terrawombat]

This post is entirely too vague.

 

What year MJ do you have? What engine is currently in it? Define cheap (give me a maximum price range). Define easy (how mechanically skilled are you).

[88pioneer]

:agree: , and usually making something more powerful means less gas mileage

[dasbulliwagen]

If you have a 2.5 4 cyl, or a 2.8 V6, your best bet would be a 4.0 swap from a donor Cherokee, that includes everything from the engine, trans, dash and engine wiring harness.... everything. Or if you have a 2.8, you could swap in a 3.4 V6 from a Camaro, If you need more power than a 4.0, well.... It aint cheap, and its extremely involved, including advanced fabrication, and or cubic dollars. Let us know what youre trying to do and what ya got and we can go from there! :thumbsup:

[88pioneer]

Also, more speed can be had with lower gearing i.e. 4.10's

[zzze]

sorry, i have an 88 4.0L 5 speed commanche, i lack any true in depth experience with engines, however, i have a friend who has swapped out a number of engines before. for price i would say anything under $1500.

[zzze]

also the idea is to possibly swap a more recent v8 that is more efficient since engines have come a long way in 23 years. i love my mj its just i want it to really scoot while still being my dd and still a capable hauler.

[Wildman]

also the idea is to possibly swap a more recent v8 that is more efficient since engines have come a long way in 23 years. i love my mj its just i want it to really scoot while still being my dd and still a capable hauler.

 

Unless you have driven an MJ with a 4.0, you'll realize real soon that you don't need a V-8 under the hood.........at best, put a stoker in, and you wouldn't have the cooling problems and fitment problems you'll have with trying to get a V-8 in there.

 

Also.......What's this???

 

for price i would say anything under $1500.

 

Is that your budget for a replacement engine??? Are you going full re-man???

 

Good used 4.0 with around 100K are selling around here for $200-$250. I'm sure that's about the same price down your way :dunno:

 

Going stoker.......ask one of them guys what they got into there engines.

[dasbulliwagen]

There are several people doing 5.3 Chevy V8 swaps, but I don't beleive you could do this swap within your budget unless you owned a wrecking yard and shop and had access to all the needed parts and fabrication tools and talent. Advance adapters makes adapters for the chevy engines, and I think small block fords for the XJ/MJ platforms, but like I said, its gonna cost ya. If you could build it yourself you might be able to do a stroked 4.0 with a header and cam, for close to your budget, but I think you may still go over even that way. If you need more than what a 4.0 MJ can give you, then you may need a different vehicle alltogether.

[Automan2164]

I think the RENIX 4.0L that is in your jeep is plenty adequate, and should be able to pull down 20 MPG with good driving in stock form.

 

Rob L.

[Pete M]

swap in an axle(s) with a better gear ratio and you'll get better performance and better fuel economy. :D

[Incommando]

http://www.novak-adapt.com/knowledge/xj_swap.htm

 

 

You'd be better off swapping in 4.10 gears

[John Richard Page]

On 7/7/2010 at 10:27 AM, dasbulliwagen said:

If you have a 2.5 4 cyl, or a 2.8 V6, your best bet would be a 4.0 swap from a donor Cherokee, that includes everything from the engine, trans, dash and engine wiring harness.... everything. Or if you have a 2.8, you could swap in a 3.4 V6 from a Camaro, If you need more power than a 4.0, well.... It aint cheap, and its extremely involved, including advanced fabrication, and or cubic dollars. Let us know what youre trying to do and what ya got and we can go from there!

I have the 4.0 in mine. I’m running 35’s right now and the truck is a bit too weak for them. I’m new to diy and am ignorant haha. What would you recommend if I wanted to beef it up a bit so I can haul lawnmowers and stuff like that. I know upgrading the gears will help but not sure what is best. Maybe even downsize to 33’s??

[derf]

48 minutes ago, John Richard Page said:

I have the 4.0 in mine. I’m running 35’s right now and the truck is a bit too weak for them. I’m new to diy and am ignorant haha. What would you recommend if I wanted to beef it up a bit so I can haul lawnmowers and stuff like that. I know upgrading the gears will help but not sure what is best. Maybe even downsize to 33’s??

Even with 33s, you'd want to regear.  For an automatic, 4.56s or 4.88s at least.  For a manual, 4.10s or 4.56s are good.

[Swampy]

I had a 2.5l on 35s and the biggest help was regearing the axles. I went from 3.55 to 5.13s. 

Now I also did an engine swap on my jeep. I swapped a '96 4.0l in place of the 2.5l and did it all for around $250 all said and done (including stuff like new oil, coolant, motor mounts, thermostat, spark plugs, etc)

[John Richard Page]

59 minutes ago, derf said:

Even with 33s, you'd want to regear.  For an automatic, 4.56s or 4.88s at least.  For a manual, 4.10s or 4.56s are good.

That

 

59 minutes ago, derf said:

Even with 33s, you'd want to regear.  For an automatic, 4.56s or 4.88s at least.  For a manual, 4.10s or 4.56s are good.

Thanks man I have the 5 speed in mine I don’t want to mess with the motor yet because Ik it has a lot of life in it but I was looking around for a new transmission. Would the stock AX 5 

 

1 hour ago, derf said:

Even with 33s, you'd want to regear.  For an automatic, 4.56s or 4.88s at least.  For a manual, 4.10s or 4.56s are good.

What are some brands you trust that make quality gear kits?

[John Richard Page]

32 minutes ago, Swampy said:

I had a 2.5l on 35s and the biggest help was regearing the axles. I went from 3.55 to 5.13s. 

Now I also did an engine swap on my jeep. I swapped a '96 4.0l in place of the 2.5l and did it all for around $250 all said and done (including stuff like new oil, coolant, motor mounts, thermostat, spark plugs, etc)

Thanks man what brand gears did you use?

[derf]

1 hour ago, John Richard Page said:

That

 

Thanks man I have the 5 speed in mine I don’t want to mess with the motor yet because Ik it has a lot of life in it but I was looking around for a new transmission. Would the stock AX 5 

 

What are some brands you trust that make quality gear kits?

I trust the brand the shop buys and warranties.

 

Installing gears requires precision work with specialty tools.  You can probably do it.  But there's a lot to be said for having a shop give you the guarantee.

[MiNi Beast]

Guaranteed piece of $#!&. 

[cruiser54]

On 7/8/2010 at 8:03 PM, Pete M said:

swap in an axle(s) with a better gear ratio and you'll get better performance and better fuel economy.

This^^. The manual trans vehicles had 3.07 gears and the ones equipped with an auto had 3.55 gears. Swap in a set of 3.55 axles. 

$1500 ain't gonna get you another motor.....

[Swampy]

12 hours ago, John Richard Page said:

Thanks man what brand gears did you use?

Revolution gear and axle

[terrygw63]

There's a lot of good info here  long story with my 86 and my ideal would be to drop this thing off and pick up later turn key. I can do a lot and have so far but would really like to get a point where I'm not working on it every time I get in it. Yeah I know   It's still a jeep. Has the very weak stock 2.8 5sp manual. Would like to swap to a much better engine and an auto ( yeah my tj is 5sp but I'm getting old) new t sure wha gears are in it currently but goal is to run st least a 33 and have plenty of power to turn them  so where's some good information that might be me through this   Tia

[89 MJ]

2 minutes ago, terrygw63 said:

There's a lot of good info here  long story with my 86 and my ideal would be to drop this thing off and pick up later turn key. I can do a lot and have so far but would really like to get a point where I'm not working on it every time I get in it. Yeah I know   It's still a jeep. Has the very weak stock 2.8 5sp manual. Would like to swap to a much better engine and an auto ( yeah my tj is 5sp but I'm getting old) new t sure wha gears are in it currently but goal is to run st least a 33 and have plenty of power to turn them  so where's some good information that might be me through this   Tia

Seeing as though you have the legendary, awesome, 2.8 V6 of fury, I'd put a GM 3.4 or 3.1 in it with a 700R4 behind it. As for gearing, I'd run either a 4.10 or 4.56 (probably the latter) in the axle(s).

[terrygw63]

Thanks I have read a little about the 3.4 swap as supposedly one of the most straightforward swaps and I'm running 4.10s on my 2.5 tj with 31s and it's not bad but figured I could do a little better running the 4.56s wanting to run 33s. This is a sentimental build so really wanting to put the time into it to make it a nice ride 

[Pete M]

8 hours ago, terrygw63 said:

Thanks I have read a little about the 3.4 swap as supposedly one of the most straightforward swaps and I'm running 4.10s on my 2.5 tj with 31s and it's not bad but figured I could do a little better running the 4.56s wanting to run 33s. This is a sentimental build so really wanting to put the time into it to make it a nice ride 

 

if you really want some extra bonus points, install the complete 3.4L with fuel injection and accessories.  it's really not that much more work if you're doing a slow build.