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XJ engine swap feasability

Re: 3.5l engine swap feasability

Edit:
I've got nothing constructive to say, other than "LS motors are cheap, powerful and reliable as well as easy to install in anything you can name"
If you want your XJ to be a unicorn, that's cool, just don't be surprised when people don't get it because LS motors are a blessing to hot rodders everywhere.
 
3.5l engine swap feasability

Hoooper said:
Im pretty sure telling you its a silly idea is constructive,
Click to expand...

There is a difference between being constructive and non constructive, saying its silly is non. Giving the reasons that is wouldn't be good like known blown head gasket, piston ring breaks, etc..... That's being constructive
 
Re: 3.5l engine swap feasability

RedHeep said:
Shit, even Bryan tried to help and Sequoia laughed at me and I'm at the top of their disliked people list :spin1:
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Not the top of the list, but close to it..... :cheers:



Well if you want to keep it mopar for some reason, I have a couple suggestions for you.

The new 3.6L in the JK is a great running engine. VVT and 4 valves per cylinder. It comes with the Mercedes WA580 5 speed transmission which is a solid trans. The 3.6L in the police package Charger puts out almost 300HP. It does have a habit of burning valves on the left cylinder head, but Chrysler seems to have fixed that issue a few years ago.

The other one I can think of is the 4.0L and WA580 that came in the Dodge Nitro. The 4.0L is just a 3.5L with a larger dsiplacement. Still is stupid wide but less issues with the engine itself. Not sure of the HP numbers but it hauls ass in the heavy Nitro/Liberty platform.

The WA580 trans does have the ability to use the new NV241 rock trac t-case from the JK Rubicon so the 4wd conversion is pretty simple. Changing the output shaft and case is no big deal.
 
Re: 3.5l engine swap feasability

I really like this ecotec option. The LK9 is the less expensive, non-VVT 2.0, but the LNF is the direct injection, VVT 2.0 that comes out of the box with 260/260. There's a GM part number bellhousing from the solstice/sky that mounts to an AX-15. Not sure if it will mount to an AW4.

I also read an article today that talked about using an air/water intercooler instead of the stock air/air one for better pressurization and less lag. The tuning options are plentiful.

I'm trying to be a little different, but I'm also trying to find a better option. XJ guys (I almost said cherokee guys, but there's a new trailhawk in the parking lot and it's not the same) are cheap, so bigger, better and cheaper are our mantra. But if toyota guys can do it with gears and 4 cylinders while shaving weight, I'd like to see if I could do the same thing.

What does a 4.0 weigh? 600 lbs? Taking 300 lbs out of the engine bay is significant. I don't know if it will be better, but I'm willing to take a look at it.
 
Re: 3.5l engine swap feasability

Another oddball swap that might be interesting is the Honda J series V6. The J37 is 3.7 litres, alloy block, and something like 300/300 hp/tq. Details at Wikipedia.

Don't know the adaptability other than there is a kit to put it in the Miata using the Miata transmission. Maybe bell housing change can fit AW4/AX15? IIRC it uses the same engine bolt pattern used on the S2000 transmission - not sure if that maps to a more desirable option.
 
Re: 3.5l engine swap feasability

As for weight... Not sure if it matters but I guess that depends on how built your Jeep is. I don't think dropping 200-300 lbs would make much difference on my piggy.
 
Re: 3.5l engine swap feasability

Root Moose said:
As for weight... Not sure if it matters but I guess that depends on how built your Jeep is. I don't think dropping 200-300 lbs would make much difference on my piggy.
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I still think that the all-aluminum 5.7 LS1 V8 is the best non-Jeep engine for a swap into an XJ. I know it isn't oddball but you get a compact, lightweight, and reliable engine with plenty of power that'll mate with the AX15 using the Novak Conversions bellhousing adapter kit. There's also an abundant parts supply for the LS1 so why go for an engine that gives away 2.2L of displacement and has questionable reliability to boot?
 
Re: 3.5l engine swap feasability

Some of the most capable rigs I have been around run a small 4 cyl aluminum engine.

The LS is a great option for those who want a serious increase in power.

What if you want comparable power to the 4.0L from a smaller and lighter engine. An aluminum block lightweight engine has its merits to be sure. 300lbs would indeed make a difference. I can tell my rig wheels different with a passenger in it, so 300lbs less weight would be nice.
 
Re: 3.5l engine swap feasability

RedHeep said:
Shit, even Bryan tried to help and Sequoia laughed at me and I'm at the top of their disliked people list :spin1:
Click to expand...


:confused: You're not Letterman...?


I make fun of everybody.
 
Re: 3.5l engine swap feasability

Bryan C. said:
Some of the most capable rigs I have been around run a small 4 cyl aluminum engine.

The LS is a great option for those who want a serious increase in power.

What if you want comparable power to the 4.0L from a smaller and lighter engine. An aluminum block lightweight engine has its merits to be sure. 300lbs would indeed make a difference. I can tell my rig wheels different with a passenger in it, so 300lbs less weight would be nice.
Click to expand...

You Need To Find Some Skinnier friends
 
Re: 3.5l engine swap feasability

Root Moose said:
As for weight... Not sure if it matters but I guess that depends on how built your Jeep is. I don't think dropping 200-300 lbs would make much difference on my piggy.
Click to expand...

It depends what your junk weighs, I suppose, as to how big a difference that makes.
I think my '98 4.0 / auto / 4wd weighs in about 3400 lbs. Knock 300 lbs worth of powertrain off and we're talking 8.8 % of the total.
Figure, right now with bolt ons, I'm making 200 at the crank. 17 lbs per horsepower. With an engine of same power & 300 lbs weight savings, we are at 15.5 lbs per horse. Equivalent of same weight but making 215 at the crank... and less strain on everything.

If you can get an I4 making 250 and weighing 300 less (I'm sure you can, but don't know which) you're at 12.4 lbs per horse. Way faster.

For comparison, an LS 5.3 makes ~310 and weighs 520 fully dressed. Jeep 4.0 makes 190 and weighs 550 or so.
 
Re: 3.5l engine swap feasability

For comparison... My overlanding Jeep weighs ~4100 lbs empty. Loaded with the whole family and gear is ~4800lbs lets say - probably light at that. Taking a couple hundred pounds off that... Not really the point of a swap to reduce weight for this kind of rig. Sure it helps but shouldn't be the focus IMO. It's like a third order benefit.

FWIW, while I enjoy talking about swaps I'm not likely to do one myself. At this stage of life and being a hobbyist I don't have the hundreds of hours to dump into a Jeep build at that level. At least not this Jeep. The stripped MJ in the shop is another time sink. I can manage a stroker I think and will likely do one in the next year or so. It's either that or switch platforms. I'd rather dump that kind of hours into a race car project or a muscle car restomod.

Different strokes and all that.

Btw, the J series engines are cheap... like under a grand or much less depending on which one. Just to throw that out there.
 
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Re: 3.5l engine swap feasability

Yeah once you start getting up higher in the weight range, it obviously takes a larger amount of weight reduction to start noticing a difference.

But if you go into everything with the "well I already weigh X..." mentality, you'll soon weigh a shitload more than if you were conscious of it.

My rig is a pig anyway. I haven't weighed it, but my sprung weight over my front end is around 2200 lbs (calc'd based on spring rates).
 
Re: 3.5l engine swap feasability

yossarian19 said:
If you can get an I4 making 250 and weighing 300 less (I'm sure you can, but don't know which) you're at 12.4 lbs per horse. Way faster.
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An I4 making 250hp would have to be a turbo model so you could at least have 250lbft of torque to go with it. However you're still left with the headache of finding a suitable drivetrain to go behind it, sorting out wiring/electronics, making your gauges work, and a whole host of other small things that'll bite you on the butt.
I'm not trying to be negative here but just stating that unless someone can actually make such a combination work in an XJ (props to the person who does), it'll be nothing more than hypothetical.
 
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