Planning on a 2012 Chevy LFX engine transplant-need help

[djwarner]

A year ago my wife's 2012 Camaro with 21K miles was totaled in a rear end collision by a box truck. While rear was severely damaged, the engine compartment remained intact.

 

Earlier this month, the car came up for salvage auction and knowing the engine condition, I bid and won the auction.

 

The stock LFX engine produces 323 HP and only weighs the same as my L24. the 6 speed AT weighs about a 100 lbs more than a Datsun AT but is located near the center of mass so it shouldn't make much difference. Interestingly, the engine has exhaust manifolds cast into the heads and makes a neat 21" wide package.

 

I have a source for modifying the engine wire harness, and plan on using Speed Hut CAN Bus gauges. But I have a couple technical questions to answer, namely engine and transmission mounts and drive shaft.

 

The engine mounts on the LFX is cast aluminum and sits on thick rubber pucks. The pucks are oriented vertically. I imagine the aluminum castings can be removed and replaced with fabricated mounts mating to the existing cross member mounts. But I've been wondering if any LS mounts might be a good candidate?

 

I know the crank shaft on my L24 tilts down some 3 degrees at the rear of the engine and this aligns the drive shaft with the differential. The MYB AT from the Camaro uses a rubber flex plate to couple to a 2 piece drive shaft, Since the Datsun AT has a spline joint to accommodate any length variation as the rear suspension is exercised, what is the appropriate drive shaft design for this transmission.

 

Third question is about the power steering pump. Since it is an integral part of the serpentine belt, I was anticipating leaving it there and running a hose from the outlet back to the inlet. Any other suggestions?

  

Edited January 24, 2016 by djwarner

[NewZed]

grumpyvette has posted some good basic advice for mounting an engine.  Looks like you're not going to find much out there.  You might be the first.

 

http://forums.hybridz.org/topic/25316-want-to-fabricate-motor-mounts/

 

That transmission looks large.  Maybe just camera perspective but taking and posting some measurements might get some ideas flowing.  It's just two pictures and an idea right now.

[djwarner]

Thanks for the link NewZed.

 

I am a little limited in the accuracy of my measurements because I haven't pulled the engine yet. But the block appears to be about 16 inches compared to the 28 inches of the L24.

 

In fact, interpolating from the photos, the transmission appears rather short, measuring some 20 inches from the engine mount to the output flange. On the Z this compares to approximately 21 inches from the center of the engine mount to the fire wall. This surprised me until I realized the Datsun AT has a long tail cone added to it. It looks like I might have to position the engine further aft of the engine mounts to secure the transmission mount plate.

 

I will know more once I get the engine/tranny pulled.  

[Xnke]

If the car was rear-ended as bad as you say,  I personally would remove that transmission and either junk it or have it gone through. Serious compressive forces may have been exerted on the tailshaft assembly and this can cause significant internal damage. Been there, done that too many times with used engines.

 

On the other hand, you got to see the damage so you would be able to determine if the risk was enough for you or not.

[djwarner]

Xnke, Thanks for the heads up. I will have to take a serious look at it once we get it on a lift to remove the engine. My wife was a actually doing at least 35 MPH and coasting when she was hit. the passenger rear tire was moved 4 inches forward compared to the driver's side, so the possibility is there.

 

Doing some rough measurements before pulling the engine, it looks like the engine/tranny combo may be too short to put the Camaro mounts on the front cross brace and have the tranny mount reach the fire wall. The block of the LFX is only 17 inches compared to the 28" on the L24. Distance from the LFX engine mount to the tranny output shaft is 20 inches while the mount to the firewall is almost 21 inches. 

Edited January 26, 2016 by djwarner

[Xnke]

Talk to Six_Shooter here.

 

He's installed the slightly older LX9 engine into his 240Z, although he used the Nissan FS5R30A transmission to do so.

[djwarner]

I've been frustrated looking for a candidate Z to receive my LFX/6L50 with the added technical problem of devising an engine mount. Just about any local candidate is extremely rough and/or missing tons of serviceable interior components. This doesn't even mention the price being asked for rolling shells. Considering what hybrid Z's are going for these days, it's getting hard to make any economic sense.

 

While looking for mounts I've found a company that makes one to fit the LFX into the Miata who might be willing to design/fabricate one for the Z. Frustrated in finding a serviceable Z, I've begun looking at a Miata candidate. Being readily available, I find they are also have similar weight and wheel track to the Z. Also they offer antilock brakes, air bags, etc.

 

So before taking to the dark side, I'm putting out the call for anyone with a serviceable Z that they would like to see living a happier, longer life. Obviously, price would be dependent on completeness and condition. I'm not a sheet metal worker. Engine and transmission condition is obviously not important as they will be replaced

.

Please PM with candidates, otherwise your comments on the Miata would be welcome in this thread.

[djwarner]

I've gotten the Z up on a lift to check mounting options for the LFX/6L50 combo. Doing this to help others who might want to go this route as well as keeping my options open.

 

The tranny mount points look strong and would be a good starting point to lay out an installation. Because the LFX is shorter and has a different mount position than the L24, using the tranny mount points would put the LFX engine mounts about 5 3/4 inches aft of the center on the Datsun engine mount towers. This suggests using a cradle mounted across the front rails. It would require removing the Datsun towers to provide clearance for the alternator and AC compressor, but otherwise everything else fits quite nicely.

 

Does anyone see a problem mounting the cradle across the top of the rails rather than underneath like the front cross member? Would you need to re-enforce the rails because you are now loading and extra 150 lbs per side?

 

Comments welcome.

[Never2BeFinished]

Neat engine swap! You probably are the first to swap one in. 

 

As far as the cradle goes (and im no expert, so just an opinion), mounting it from the top should be fine as long as you use bushings. Solid mounting increases vibration throughout the car. 

 

I have seen the motor mounts/towers from the original cross member cut off many times when a new cross member is used, which (I think) answers your question about the alternator and AC compressor. May be worth trying to make the AC work... since you have the compressor, you could probably source other Camaro AC components? Up to you and your goals obviously. 

 

Good luck with finding the candidate car!

[LLave]

That is an awesome engine swap. You will definitely hit some road blocks, you are designing (dare i say engineering) and fabricating something that has not been done before. There are no off the shelf parts. But that is what makes it cool.

 

I would suggest fabbing something like this:

https://liquidironindustries.com/GM-LS-Motor-Mounts.html

 

Poly performance sells the urethane bushings:

http://www.polyperformance.com/TRUCK-BUGGY/Fabrication-Parts/Bushing-Bearing-Kits

[Xnke]

We do have a member here with the previous generation of this engine in their Z already. I'd PM Six_Shooter and ask for a look at his engine mounts...

[67LS1]

Well I wish I had seen this post 4+ years ago.

i swapped a 2013 LFX and 6 speed auto into my 1966 Chevelle to use as a daily driver. My goal was to get 35 mpg but I’ve only managed 32. Not complaining.

I can answer a lot of questions about mounts and the proper driveshaft mods, etc.

did this swap project ever move forward

[djwarner]

Nice Work 67LS1,

 

You must have some unique experience and knowledge.

 

As for my project, after not finding a suitable roller Zcar and considering the modern design features of a Miata such as airbags and antilock brakes, etc, I decided to swap the LFX/6L50 into a 2011 NC Miata Touring edition. While others had swapped in LFXs with 6sp MT for racing, I decided I wanted a true daily driver with functioning AC, antilock brakes, power steering and a full functioning instrument panel. My swap was the first 6L50 swap into a Miata. As such, the project took 13 months to get back on the road. Another 12 months to refine the project - get the paddle shifters to work and tuning the engine and transmission. I've put some 6000+ miles on the car since the swap, driving it daily.

 

The 2 major issues in the swap was relocating the AC compressor and power steering pump with a custom bracket, and learning enough of the wiring harness and GMLAN system to integrate into the Mazda electrics and CANBUS. Very little body work was required. Back then there were no 3rd party wiring harnesses or other kits to support the swap. I named my car GRIFFIN, a chimera, half lion and half eagle.

 

With larger intakes and exhausts and tuning, I am putting something over 300 hp at the wheels. Torque scheduling at low rpms has proved to be something of a problem as anything approaching available torque below 2800 rpm results in unintended burnouts. Fortunately, the LFX engine management system is based on a virtual torque model (actually a 6 dimensional table predicting available torque at various operating regimes). Manipulating this table tells the ECU at low rpms, that actual torque available is lower than what the engine can actually produce. Once the virtual torque value is achieved, the drive by wire throttle closes somewhat to maintain what the model says. As the rpm climbs or a higher gear is selected, higher torque limits allow for full throttle operation.  

 

Someone asked me about gas mileage and I honestly had to admit I can't stay off the gas long enough to get a good estimate. Even with thrashing it, I do get 25MPG on premium. Smiles per mile has yet to be determined. 0-60 times are sub 5 seconds. I haven't taken it to the drag strip yet.

[67LS1]

Jeez, I should have been calling you for advice. Nice looking swap.

What can you tell me about how you relocating the AC compressor? I could not run one due to frame interference and would really like to add it back.

Also, did you end up running the BCM from the Camaro? I did not and one thing that I lost that still bugs me is the loss of voltage control. It stays at 13.6 full time. 
How does your exhaust sound with Helmholtz Chambers?
Dennis

[djwarner]

Hi Dennis,

 

The OEM BCM anti theft system is horrendous cannot be defeated without the GM hardware.

 

I found a third party BCM replacement because the firmware in the TCM only recognized the Paddle Inputs that came through the GMLAN. I had also hoped to get the GM cruise control working but the design of the BCM was originally designed for LS engines. It does have the charging control you are looking for.

 

http://oecontrols.com/

 

Bob Valentine there can give you the details.

 

As for the AC Compressor, I mounted a small Sanden compressor where the OEM PS pump was located. I had room to mount the PS pump below it. Had to design a bracket that mounted on the front of the crankcase. I got away with the smaller compressor because the cabin of the Miata was so small. I made samples out of hardwood before having a local machine shop cutting one out of 1" aluminum plate. Of course I ran into problems clearing the steering rack with the first attempt and had them make version 2.0. The problem with using a local machine shop is that one off pieces have zero priority and long delays for production work extended my build time.

 

If I were to do it again, I would use two pieces of 1/2"  aluminum plate. I did have to get a slightly longer drive belt to adjust for the changed locations.

 

The Helmholtz exhaust system was designed to fit on a 350Z. At lower rpms it is fairly quite. At 2000 RPM and above, it pretty much sounds like a straight pipe. I would caution to keep the X pipe or H pipe in the exhaust. 

Edited July 19, 2020 by djwarner

[67LS1]

I built my for mpg. I’ve had LS Chevelles so though this might be a new challenge. I even managed to keep the weight down to 3,170 lbs with a full (20 gallon) tank.
The OE Control box is too rich for my blood just for voltage control I would like. 
I might be able to use a smaller AC compressor like you because while my cabin is larger we don’t have the humidity here in Nor. California. I’ll have to look to see if the larger diameter PS pulley will clear my steering shaft when moved lower. It it will The smaller compressor and location swap may work for me. 
Thanks for the tips. I’m glad I dared revive a 4 year old post.

dennis