Higher horses, higher revs & even higher torque, a streetable LJ engine swap

[toximus]

Look what showed up!

It's very green! Lol.

The transmission is supposed to arrive on Thursday or Friday.

 

[toximus]

The 6L80e transmission arrived from Zero Gravity Performance!

When I saw it almost hanging over the edge of this tiny pallet I was worried it might have been damaged in transit but thankfully I don't see any damage.

I'll need to figure out a dip stick solution.

Does anyone know why there's 2 "drain holes" in the front portion? One has a loose cover and the other is open.

This shallow pan is 2.5" tall at the high side and is part number 24239533. It appears to be the exact same pan as the G8 pan which is part number 24239528.

Here's the comparison with a 42RLE pan:

Once I pull my transmission I'll post more comparisons of the size.

 

[toximus]

Coming back to the dash discussion, I am finding that keeping a traditional gauge cluster is something that is more work for 1) the data I want available and 2) with the way I use my Jeep.

Instead I decided to take a page from what works with Ultra4 race cars and I chose to go with an AiM digital dash.

Sure, it's ugly and not very "classic Jeep" looking which does bug me. But it can display any data that's available on the CANBUS or via additional sending units, it can do calculations right on the dash (for things like speed correction), I can selectively choose to display only relevant data, it's rugged, water resistant, works in hot and cold temperatures, boots in 3 seconds, autodims for night, and it's expandable if I need to add more data later or customize a view.

Talking with AiM and CANTrolls, it's sounding like for the AiM dash to fully understand the GM CANBUS I will need to have it custom programmed. In the end, I will be able to view all of these parameters on the dash:

• Engine RPM
• Vehicle speed
• Engine temp
• Voltage
• Engine oil pressure
• 6L80e transmission temp
• 6L80e current gear position (ie PRND654321)
• Odometer or engine hours (I'm still not positive how I want to deal with this.)
• Check engine light
• Vac/boost

If anyone else is interested in using the AiM dash with the custom GM CANBUS programming, let me know. Since I am paying for the custom programming I can resell the integration at a fraction of what I am paying (hopefully a win/win situation). As far as I'm aware, this will only work with the E38, LS3, and 6L80e.

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Just a few more little updates. The Atlas sounds like it's been delayed by another week so I may not be seeing it until mid-September.

I added studs to my shopping list for connecting the Atlas adapter to the transmission.

 

[gt1guy]

https://www.lokar.com/trans-dipsticks.html

I bought the firewall mount one. More than long enough to reach the firewall on my JK and the engine is moved to the rear 4". I have a 6l90 that is 1.5" longer than the 80, but I have no idea if the dipstick location is farther back or not.

 

[toximus]

Still waiting on the Atlas to get started... :( Trying to distract myself with other things.

ACDelco 24205899 is the plug for the smaller inspection hole on the 6L80e:

 

[toximus]

The custom harness for my LJ came in from RPM Extreme! 😁

 

[toximus]

Still no transfer case, but winters setting in fast and hard so I decided to get things rolling anyway since I won't be going on any trips soon anyway.


I went for a drive to heat all the fluids up and get them mixing for one last time. To help with selling the engine later I took a video of the engine running and pictures of the mileage. While I was draining the fluids I collected samples to send to Blackstone.

 

[toximus]

Look what showed up!

 

[toximus]

I managed to get the 128lb box into the garage and found my new Atlas inside!

The output shaft is super short!

Unfortunately the adapter is missing the bolts/studs to attach to the transmission... Hopefully they can get those to me before another 6mo is up...

 

[toximus]

Wait wait wait! I found the studs! If you look closely at the first picture they're packed with the oil. Woohoo!

 

[toximus]

First order of business is bolting on the accessories to the engine. My thought here is by doing so I'll have a good idea of the final physical size and get more familiar with the engine outside of the Jeep.

Because I'll be operating my Jeep (and thus engine) at various extreme angles I decided to add in rear steam vents to the block. This video helps explain the reason why LS engines need steam vents:

https://www.youtube.com/watch?v=e2_twsAziZ0

Later model LS engines like mine block off the rear steam vents with a rivet of sorts:

 

[toximus]

To get the plugs out I decided to place my engine on a stand and rotate it upside down to drill them out. This way all of the chips would fall out vs falling into the coolant passage.

I bought a cheapy Harbor Freight 750lb engine stand (which I would not recommend if you want to use it long term... it's very difficult to turn and doesn't feel very stable.).

To get the engine onto the stand I used a lift plate from Motion Raceworks (https://www.motionraceworks.com/products/gen-4-ls2-ls3-ls7-lsx-engine-lift-plate) and the hoist.

Intake removed:

After I removed the valley cover I bolted on the lift plate:

The rear vent plugs:

I bolted the engine to the stand with class 10.9 M10x1.5 70mm long bolts (https://www.mcmaster.com/93474A228/). And then rotisseried the engine upside down and drilled the plugs out. I'm pretty sure GM pre-fills these crate engines with oil because a few quarts went all over my garage floor... :(

With the engine upright again I loosely bolted on a steam vent kit I bought from from Motion Raceworks (https://www.motionraceworks.com/pro...sover-steam-kit-for-low-pro-plastic-intakes):

For the front I decide to leave the OEM LS3 vents on for now. Once I have a better idea of how I'm routing hoses I'll make a decision if I'm replacing them for the billet ones like the rear.

 

[toximus]

To give myself a head start with making my own motor mounts, I bought engine side plates from Kartek (KTK34191). Because the crate engine doesn't come with many of the necessary bolts, I decided to dress her up a little bit and attached the plates to the block with stainless steel bolts from ARP (434-3103).

 

[gt1guy]

Just remember that the block is aluminum. Stainless bolts will need something on them to keep from welding themselves in place.

 

[toximus]

Just remember that the block is aluminum. Stainless bolts will need something on them to keep from welding themselves in place.

Noted. I still need to look into the best options. I have the hardware store antiseize but I want to make sure I'm doing it right on this engine.

 

[toximus]

Today ended sooner than I would have liked with a Dawn dish soap shower... But, at least the transfer case is out... More tomorrow.

 

[toximus]

Here's the 42rle next to the 6L80e:

Out with the old:

I'm might have to bring the pressure washer into the garage...

From the rear you can see how narrow the line 6 is:

 

[toximus]

Tomorrow's supposed to be a steamy 50F so I put off washing the engine bay and cleaned up the garage today and did some fun driveline comparisons instead. There is many size and proportion differences between the two and both aren't aligned the same in these pictures, and thus this comparison isn't meant to be exact science, rather just a brief look with rough measurements.

Measuring from the front of the accessory belt to the face of the rear yoke:

• The total length of the stock 4.0L + 42RLE + NP231 is approximately 68-1/2".
• The total length of the LS3 + 6L80E + Atlas 2 is approximately 63-3/4".

How that breaks down for the stock driveline:

• 4.0L - 30-1/2"
• 42RLE - 24-1/4"
• NP231 (with SSSYE) - 13-3/4"

How that breaks down for the new GM driveline:

• LS3 (with corvette belt spacing) - 24-3/4"
• 6L80E (includes 4" adapter) - 27"
• Atlas 2 - 11-3/4"

The Jeep raised up quite a bit without the weight of the driveline:

In this picture, the 6L80E pan gasket is on the bottom with the 42RLE pan on top. The 6L80E keeps the pan under the transmission while the 42RLE rotates the pan to be wider. Because of this I think I'll have some more room for the front driveshaft.

• 42RLE pan width: 14-1/2"
• 6L80E pan width: 12"

 

[toximus]

When I was researching the 6L80e I couldn't find any comparisons to the 42RLE so here's some more pictures with them next to each other aligned the same.

This picture is a bit deceiving due to the perspective, but the small area that shows through on top of the 6L80e is the biggest area of difference:

With the pans sitting on the same level surface, the centerlines (ie. input and output centers) of both transmissions are at roughly the same height.

And lastly I washed the engine bay and my garage floor before pulling the Jeep back in:

 

[toximus]

I set the frame at ride height and placed the front axle at full bump and then lowered the new engine down:

I bolted up the transmission and am pretty happy with how it's packaging. The LS is definitely a different shape than the I6. I'll know a lot more how it needs to sit once I get the Atlas in the rear.

I need to find a cover to fill this gap between the engine and transmission:

 

[toximus]

I had thought that I would be placing the engine as far forward as possible, but it's actually sitting better further back and further down. I moved the engine back further and it's touching the firewall now. I'm thinking about giving the firewall a few taps to make room but I also don't want to shatter the heater box behind it.

The AC condenser was removed from the firewall to make room:

The CTS-V exhaust header is barely touching the old frame side engine mount (which I can remove). But I'm not sure the engine needs to go down any further anyway. If I move the engine down further the header also threatens dumping onto the UCA and not leaving enough room for an exhaust pipe. Once I get the Atlas tucked up I'll be able to correctly set the engine position.

The clearance against the RJ60VXR axle is looking good and has more room that it can come down if needed.

At least with the engine further back and down I won't have to cut a hole in the hood for the alternator to stick out of anymore! The coilover hoop brace fits in which was the highest point.

I need to whack the tub floor to make more room for the Atlas. It's a big boy! Right now it sticks 1-1/4" below the bottom of the frame.

I still need to figure out where the AC compressor can fit on the accessory drive. The Holley low profile mount looks like it will sit about 1" into the frame rail. Which is no good...

 

[toximus]

I cycled the axle several times and it's tentatively appearing that the cast aluminum pan that came with the LS crate engine is going to clear everything just fine. As long as I place a skid under it, what do you guys think about running it?

 

[gt1guy]

Problem with the cast aluminum pans is that a kicked up rock can punch a hole in them. They don't have any give like a steel pan does. I bought the Pacific Fab steel pan for mine.

 

[toximus]

Problem with the cast aluminum pans is that a kicked up rock can punch a hole in them. They don't have any give like a steel pan does. I bought the Pacific Fab steel pan for mine.

I've heard that argument around but I can't find any actual evidence of that happening... at least with skids being used.

 

[gt1guy]

I haven't either, I didn't want to be That Guy. I know my luck.

The steel pan I bought is also a bit shallower and narrower, so if things get tight with the alum pan and you need a couple inches...............there's help.

 

[toximus]

I haven't either, I didn't want to be That Guy. I know my luck.

The steel pan I bought is also a bit shallower and narrower, so if things get tight with the alum pan and you need a couple inches...............there's help.

You could be totally right about it cracking... It could be that nobody runs them, because they crack, so we don't actually end up seeing any that crack...

I was initially thinking that I'd need to run an aftermarket pan for clearance and relocate the oil filter but now that I've cycled the axle that area seems to be the least of my concerns. Which seems odd to me since that's not what I was expecting at all. In fact, I might be able to run a larger driveshaft instead of a tiny 1.5" shaft. Don't quote me on that yet, once I get mounts tacked in place I'll probably realize huge issues... Lol!

 

[toximus]

My arms ache and my hands have blisters. Now I know why they call it body work... But I think I will be able to get a flat belly skid in!

To get the room I needed for the Atlas, I had to cut a half moon out of the driver's seat support around the trans tunnel. I learned this trick from mrblaine . After that, I beat and beat on the sheet metal until it raised up to meet where I cut it.

I removed the seat to make the cut, but put it back before hammering so that it wouldn't warp.

I inked my line before cutting:

Cut the slice out:

Difficult to see in the picture, but the lower sheet metal now meets the higher cut. I'll paint this later.

Tucked!

The area lost inside the Jeep is minimal since it's mostly under the seat and console area. My right foot generally sits on the gas peddle so the area lost isn't anything I'm going to miss.

 

[toximus]

I found it on sale, so I ended up buying a Holley 20-160 low profile AC compressor to see how it fits. It barely fits and requires lifting the engine to fit the compressor in.

There's a 1/16" gap between the compressor and the frame:

To account for the engine moving under load, I'm going to notch the frame in that section and weld back in a plate to make room for the compressor.

I really like how the compressor sits down there instead of up high.

To further clean up my accessory drive, I'm considering moving the alternator over to the right side closer to the battery and PDC. This way I won't have to run a cable over top of the engine.

The GoatBuilt 4405 and 4406 brackets seem to fit the bill:

Now I need to decide if I want truck spacing (tucks the alternator in tighter) or f-body spacing (gives me an extra 3/4" in front of the engine for more coolers or a bigger fan).

 

[gt1guy]

Isn't the thermostat neck going to be in the way of the belt running the low ac and high alt on the right side?

 

[toximus]

Isn't the thermostat neck going to be in the way of the belt running the low ac and high alt on the right side?

Good eye, the low AC runs off it's own belt. 👍