Hopefully a different engine swap thread?

4BY4ADV

4BY4ADV

TJ Enthusiast
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Been doing a lot of reading on engine swaps, different options, etc. It seems like the majority of the threads are focused on horsepower and cost.

While I'm interested in power... or say, not losing power, I'm more interested in potential fuel economy gains. I'm also in the communist state of California, so I have more limitations on swaps as well.

That being said, I know in other posts there has been hate for the R2.8 based on cost and lack of HP compared to V8 swaps. I'm okay with the "slow/modest" acceleration I have with my 4.0/AX15/5.13/35's. I have a sport bike if I want to speed. The doubling of my fuel economy however is a big incentive to swap to an R2.8. With my current monthly mileage and getting around 12mpg, doubling my fuel economy would save me around $200/month. Over a 5 year period that's $12,000 and I have zero interest in selling my TJ. I plan on keeping it until California kicks me off the road, at which point I might move to another state. ;)

IF you had similar goals of increased fuel economy longevity/reliability and had to pass CARB, is there a better option for a motor swap?

Rough estimates here....
$8,000 for engine
$1,000 for bellhousing adapter
$4,500 ish for the rest? (new motor mounts welded in, relocating trans mounts, exhaust, cooling, intake, shorten rear D/S, lengthen front D/S)

While I wouldn't be saving money, it would be close to a wash over 5 years.


I've dumped gasoline over myself.... time for someone to light the match.
 
Is your current 4.0 running/passing smog, and will go for another five years?

Why hassle with motor swap and spending 10-15k now?
A few bucks on fuel costs vs taking 5-10K & investing it for 5yrs, then do a motor upgrade/swap.
 
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It's running, however I'm not sure I'll pass smog this next time around. Oil leak, intermittent missfire, going to need to replace the exhaust soon since the muffler is cracking and I'm guessing when that gets replaced... I'll find more fractures (like the exhaust manifold I just replaced). The Jeep will stay with me well past 5 years, so I see the engine swap as being a longer term investment than 5 years... that's just around the point where financially the ROI pays off.
 
Jeeps and good fuel economy just don't go together.

1. Maybe sell you TJ and buy one of the 4 cylinder models?

2. Buy a different vehicle for DD purposes

3. Buy one of the new hybrid JL's

My wife's Prius gets great gas mileage, but the top and doors won't come off... :D
 
1. I'd be further screwed by the time I lifted the 4cyl, put a rack on with my tent, loaded up my camping gear, etc.
2. Something about driving the TJ with the top down and music up. I've had other daily drivers, motorcycles, etc, I never got the same enjoyment.
3. Besides the fact I just don't have interest in the hybrid JL, by the time I'm in the JL, get it set up the way I want it, I'd be in it over $50k. While this isn't necessarily about the financial cost comparison, a new motor in the TJ is a much more sound financial decision.
 
Apparition said:
Can you do all the work yourself?
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Some. My limitation is welding. I've pulled/reinstalled motors, auto to manual trans swap, full wiring harness replacement, etc on Nissan's when I used to have a 300ZX TT.

I think where I'm going to need the shop is welding in new motor mounts and modifying the trans mount for being pushed back, something I've read on another R2.8 swap.

So, realistically, I could tow the Jeep with no motor, ready to have the motor mounts welded and motor dropped in place, then tow home finish the rest except for exhaust, then have exhaust fabbed up.

At some point I'd really like to learn to weld.
 
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4BY4ADV said:
Some. My limitation is welding. I've pulled/reinstalled motors, auto to manual trans swap, full wiring harness replacement, etc on Nissan's when I used to have a 300ZX TT.

I think where I'm going to need the shop is welding in new motor mounts and modifying the trans mount for being pushed back, something I've read on another R2.8 swap.

So, realistically, I could tow the Jeep with no motor, ready to have the motor mounts welded and motor dropped in place, then tow home finish the rest except for exhaust, then have exhaust fabbed up.

At some point I'd really like to learn to weld.
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You could always get a mobile welder to come to you.

As long as you can do most of the work that will significantly help costs.
 
Apparition said:
You could always get a mobile welder to come to you.

As long as you can do most of the work that will significantly help costs.
Click to expand...

OOoooo... I didn't think about that as an option. That is a REALLY good idea. And personally, I like doing my own installs as I get to ensure wiring is routed the way I want, etc.
 
4BY4ADV said:
OOoooo... I didn't think about that as an option. That is a REALLY good idea. And personally, I like doing my own installs as I get to ensure wiring is routed the way I want, etc.
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Be prepared to be nickel and dimed to death too. I'm waiting on an LS to arrive that I ordered and I've got a lot of supporting components to buy in order to make it all work.
 
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Apparition said:
Be prepared to be nickel and dimed to death too. I'm waiting on an LS to arrive that I ordered and I've got a lot of supporting components to buy in order to make it all work.
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Yeah I'm expecting that, however one of the things appealing about this swap is what comes in the kit, not to mention using my current trans.
 
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4BY4ADV said:
OOoooo... I didn't think about that as an option. That is a REALLY good idea. And personally, I like doing my own installs as I get to ensure wiring is routed the way I want, etc.
Click to expand...
You could also get a nice MIG welder and learn to weld, MIG welding is super easy to pick up on, and a few days practicing on some scrap metal. Save some $, end up with a new skill and tool that will be useful indefinitely. Honestly could post pictures and theres enough good welders here that can give feedback on your welds to get it dialed in before you tackle the MM's
 
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I've done the R2.8 swap and do really love it, but it's a pricey swap. For all practical purposes rebuilding your 4.0L is the way to go.

IMO to even consider the R2.8 I would do it if you love your vehicle and want it to be a Swiss Army Knife kind of vehicle. Or you're comparing it to a new vehicle and you prefer a TJ and a slightly smaller price tag, but WAY more work to a new vehicle. However IMO a TJ is kind of a perfect blend of an old simple vehicle, but with a few good modern suspension and drivetrain components.

You might not get double than what you're currently getting in MPG. Typically you'll 40% better fuel economy if all else is equal for a diesel. Originally I got more than double MPG though, but with tires, gear ratio, lift, winch, roof rack, etc I'm getting around 20 mpg now, but I was getting 11 mpg before, though I never properly geared that vehicle. 5.13s are a bit high for the R2.8. I assume those are built axles too, which means you could probably trade someone with 4.10s and Rubicon axles or something or test and see if it matters at all.

The R2.8 is slow, but it's torquey (I think I was racing a TJ Rubicon before, but it's hard to tell, but I only started winning once we hit around 50 mph). I'm also a bit hesitant to be aggressive, because it's a Jeep, so if you're not used to people passing you then you don't spend much time on the road. Also a new R2.8 vs high mileage AX-15 might result in a broken AX-15. Though I do want to get a tune which will even risk the AX-15 even more with 60 lb-ft more than I've currently got. I'm pretty much only interested in torque and though you can get there with any gas engine and gearing, I prefer diesels, for a bunch of reasons.

Another note and not to be a butt, but AVOID HYBRIDS. They're great until they aren't. You're in CA so at least you have some support, but I've got nothing unless I want to spend insane prices for the dealer to fix and in that case changing spark plugs practically totals the vehicle out. IMO go electric with an on board generator.

Back to the subject. You can get by for just a few thousand beyond the initial price, but you will need a lot of time and skill to overcome everything. If you want to be done in a couple of months, unless you're highly skilled, you'll need a kit and most are around $12k or something at this point. One of the big issues is the narrow cooling package and I've got $4k in radiator and intercooler including brackets. It's beautiful, but expensive. IMO my engine typically runs too cool, but it's a long topic.

Oh I ended up stick welding my engine mounts and I've only stick welded a handful of times, but I was having issues with my welder and didn't want to do anything smart, like borrow a welder or buy one or get a professional welder to do it, though I work with professional welders...The welds look horrible too, but they've lasted so far and I inspect them often.

I actually made a video on this because I do get a few questions and though I would gladly write you a novel, you'd get even more bored so see below...I might have a couple more videos too.

 
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suicideking said:
Jeeps and good fuel economy just don't go together.

1. Maybe sell you TJ and buy one of the 4 cylinder models?

2. Buy a different vehicle for DD purposes

3. Buy one of the new hybrid JL's

My wife's Prius gets great gas mileage, but the top and doors won't come off... :D
Click to expand...

Couldn't agree more (y)

Though the 4 cylinders don't really get much better MPG unless they're in stock form. Even then it's negligible.
 
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BugoutJeep said:
IMO to even consider the R2.8 I would do it if you love your vehicle and want it to be a Swiss Army Knife kind of vehicle. Or you're comparing it to a new vehicle and you prefer a TJ and a slightly smaller price tag, but WAY more work to a new vehicle. However IMO a TJ is kind of a perfect blend of an old simple vehicle, but with a few good modern suspension and drivetrain components.
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You've nailed it there. I love my TJ over JK/newer and all the additional electronics.

BugoutJeep said:
I assume those are built axles too, which means you could probably trade someone with 4.10s and Rubicon axles or something or test and see if it matters at all.
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That's another thing I'm looking at. While I'm running 5.13's, E-locker in the rear, and posi in the front, it's the Dana 30/35 combo that the PO built. I don't plan on keeping those under the Jeep long term, so even if I stay with the 4.0, the axles are going. I'm not going to factor that cost/regearing into the equation for that reason.

BugoutJeep said:
so if you're not used to people passing you
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Before I had the TJ, I cared. With the TJ, I enjoy the drive more than caring if I'm being passed. To the point now where I'll have a rental vehicle for some longer business trips and I find myself going too slow because I'm just used to it now.

I'll definitely watch the video after work tonight.
 
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Chris said:
Couldn't agree more (y)

Though the 4 cylinders don't really get much better MPG unless they're in stock form. Even then it's negligible.
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I think my Granddad used to be able to get 20 mpg from his 4 cylinder YJ, but he was really hypermiling and stuff. IMO you get to a point it just doesn't make sense to have a Jeep though.
 
BugoutJeep said:
I think my Granddad used to be able to get 20 mpg from his 4 cylinder YJ, but he was really hypermiling and stuff. IMO you get to a point it just doesn't make sense to have a Jeep though.
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Absolutely! I've seen some of those guys who hypermile and it's pretty insane.

Even if you can put a more fuel efficient engine in a TJ, it doesn't change the fact that you're trying to move one of the worst aerodynamic, heavy vehicles down the road.
 
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