gm atlas (LL8) engine swap? who has done it?

s346k1 · Jul 7, 2013

anyone done this?

I searched and came up with absolutely nothing. it looks like a great alternative to the lsex swaps. the engines make ok power in stock trim, but in typical gm fashion they are quite restricted. full exhaust and a tune would easily put them over 300/300. i'm considering this for ease of exhaust routing, engine placement, etc. there's nothing wrong with my 4.0/aw4 at this point. I think it'd be a cool swap that is somewhat easier than say an lm7 and make comparable power.

i'm very familiar with the lsx engine and would love to do the swap, but to do it right looks very expensive. too expensive to justify in a vehicle that sees no offroad use and is basically a DD.

yossarian19 · Jul 7, 2013

I've thought of the inline swap a lot but can't see how it would be cheaper than ls swapping. Go for it and take pictures though

Vanimal · Jul 7, 2013

i think if i did anything but an ls swap, i'd do a gm supercharged 3800.

IslanderOffRoad · Jul 8, 2013

Its not a motor with a ton of aftermarket support, that's probably why.

Ronbo · Jul 8, 2013

I thought they had a front sump pan designed with their half shafts passing through it ? Would that clear a solid front axle?

Johnnie Walker · Jul 9, 2013

They do have front sump with a hole for the shafts. Not sure if it can be turned around, at least maybe modified.

I too, long time ago, thought about this swap. But, dollar for dollar, LSx swap will cost less. Will an LL8 even FIT? They are long SOB's and go aprtially under the trailblazer firewall.

I mean, after a few years GM offered the 5.3 LM7, and the LS2 in the TBSS .. they figured it out. Haha.

yossarian19 · Jul 9, 2013

The "V" layout is slightly problematic in the Cherokees, though...
The LLR might be a "better" candidate if the LL8 is too long, but all the Atlas motors have a front sump. I'd love to find a motor that was a bit more modern, better power / fuel efficiency & around 250 horse, but it's a hard one to find.
The LS swap seems overkill to me, though I may feel different if I was on 35s.

kastein · Jul 10, 2013

It is an interesting idea... btw the bellhousing from 04-05 Colorados/Canyons will bolt this to an AX15 or NV3550. Not sure on input shaft length but it shouldn't be too hard to figure out.

yossarian19 · Jul 10, 2013

I'm sure *somebody* can fab their way around the front sump issue, either with a custom pan / pickup or the motor-to-axle space relationship.
Or, and I can't believe I'm saying this, one could go with a strung-out Volvo T5 engine. Short, can be tuned for decent power, *may* be mate-able to the AW4. I know, at the least, that they use the same bell housing pattern as the earlier Volvo I6 motors, which came mated to the AW71. Gawd, I hate working on Volvos, but they did put out some neat motors.

yossarian19 · Jul 10, 2013

Side note, I saw on an expo forum that a guy had put a Kubota 2.2L diesel into a TJ, strapped on a Mitsubishi turbo (IIRC) and a generic intercooler, mated it to his AX15 and spun up to 24 lbs of boost. Said 27 mpg & as much power as the 4.0

Johnnie Walker · Jul 11, 2013

yossarian19 said:
The "V" layout is slightly problematic in the Cherokees, though...
The LLR might be a "better" candidate if the LL8 is too long, but all the Atlas motors have a front sump. I'd love to find a motor that was a bit more modern, better power / fuel efficiency & around 250 horse, but it's a hard one to find.
The LS swap seems overkill to me, though I may feel different if I was on 35s.

Novak conversions makes basically everything you need to stuff the LSx under hood of an XJ. Engine mounts, headers, harness etc. Some of it is spendy, yes. But it is available, if you can't/don't want to make your own parts. And a min of 275hp to start with, you could throw a turbo or SC on it and have that much more.
I basically see the LL8 just as costly, if not MORE than an LSx swap.

Action Fab · Jul 11, 2013

I do a lot of GM LS, TPI, 5.0 ext swaps in Jeeps. And I guarantee a 300hp stroker would be cheaper than any of them.

yossarian19 · Jul 11, 2013

But would it be as reliable as a 4.8 or 5.3? I haven't seen much in the "good news about my stroker!" department. Maybe it's just that those folks aren't posting up...

Action Fab · Jul 11, 2013

If you think a swap is reliable. You're wrong. LOL

I know a ton of guys with strokers who have zero problems. I'd trust a stroker over a swap any day.

MPETESS10 · Jul 11, 2013

cost aside, I have to ask WHY? the 4.2,3.5/3.7,2.8/2.9 engines are ALL JUNK. the early 6cyl's had piston issues, and a lot of them across the board have cyl head issues, and even if you luck out and find one with over 100k and in decent shape, you still have a very limited amount of aftermarket suppoort. even if someone GAVE me one, I dont think I'd use it for much more than scrap metal.
unless you are just trying to be different, I dont see any reason to choose any member of the Atlas modular engine family for any swap, ESPECIALLY if you are comparing said swap with an LS.

CobraMarty · Aug 14, 2013

I have been looking at this engine GM Atlas I6 4200 for over a year now with the idea of using it as a longblock swap. Consider it a 24 valve 300hp longblock. Run it with the jeep ECU and bolt it/ adapt it to the AW4 or AX15 manual trans. Try and use all the Jeep accessories on it, cut off the top of the intake and run a jeep 4.0 70mm TB and all the jeep sensors. Now that the likes of 'FlyinRyan' can tune the jeep ecu. There is not a lot of aftermarket support but there is a guy who casts a rear sump oil pan, and Kooks and others for headers, and another guy for stand alone haarness and ECU tuning if going that route.

yossarian19 · Aug 14, 2013

Thats all you need - rear sump pan.
I think you might be nuts, or possibly genious, for looking to use the Jeep control system on the Chevy motor. I'd love to see it work.

yossarian19 · Aug 14, 2013

Can't find a price on any of this stuff, but http://www.emtechmotorsports.com/Products.html
Everything you should need to put an LL8 in a Cherokee. I think Lime-Swap.com sells I6 standalone harnesses, etc.
So, who's going to be first?

CobraMarty · Aug 14, 2013

The Jeep ECU doesn't know what engine it is controlling. All it needs is the Crank and Cam position sensors, IAT, MAP, TPS, IAC, O2 sensors, ignition. Using the Jeep TB and sensors address that, O2 sensors no prob, adapt or 'translate' Cam and Crank position sensors, waste spark ignition, starter, accessories.

yossarian19 · Aug 15, 2013

Hmm. How would you approach ignition control with the dizzy vs COP systems? Never done anything like that before. I suppose an 01 computer, being fed the right crank / cam sensor inputs, could drive the GM coils. That's provided the draw on the coils is correct or adaptable.

gm atlas (LL8) engine swap? who has done it?

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