tomrev's LFX Build
 

After viewing the other LFX build threads about eight thousand times, I felt I should add some little details, to add to the general info pile on this great powertrain option. I want to thank The Pass, Gooflaphase, Carnut, and LFX1999 for the great photo's, and detailed ideas on how to put things together. Because a lot of the moves have been shown in great detail, (like the engine bay cuts, diff mount welding, etc.) I will just show some minor stuff that doesn't usually show up, but caused me a lot of trial and error to get to where I was happy with it. I'v been doing engine swaps for about 40 years; seemed each car was going to be my life long keeper, but once built they either weren't as much fun to drive as I'd hoped, or i was just itching for more garage time, but I think the Miata / LFX will break that chain, and have a long life in my garage. A couple of the previous projects were a MGB-GT, with Ford 302, Lotus Eleven with a 1300 Suzuki twin cam, and a 914 Porsche, with a Honda V-6, which is where I was going with the Miata, till I started reading about the LFX.

I found a nice, clean 2002 in June of 2016, and figured I'd drive it, and start changing the things I didn't like, while looking for a drivetrain, and info on what it was going to take for the swap. The seats were pretty soft, as was the suspension, so a set of MeisteR coil overs, and FM sway bars went on, and I began the search for a better seat. I really liked the feel of the NC seats, but the back width interfere's with the rear body work when slid back. I'm a little over six ft., and with this being a street build did not want a race seat; just too hard to get in and out. I found a nice set of 2006 cloth NC seats, and made up a set of new slides that lowered them a bit, and did a minor trim to the sheet metal , just forward of the seat belt tower. That, and moving the seat belt bolt swivel back about 1/2in. allowed the seats to slide all the way back, and gave me the firmer, much more planted feel I was after. I found a fresh Camaro drivetrain on Ebay, that had only been in the yard for a few days, and was able to get the full engine, trans, AC, starter, shifter shipped to me for $3K. It had around 24K miles, and was a car that had been hit in the rear. Once that arrived, I needed to start saving up the $$ for the swap, and began looking at the blogs for clues to the process, and doing little things that would need to be done, like drilling/tapping oil sender, water temp senders, etc. Also found a Cadillac diff, so that could get fresh axle seals, and new mount bushing installed.

For the last year I'v ordered and received all the install parts from V8R, and had them make me a wiring harness, and flash the ECU. After driving the car into Fall, I started advertising the stock drivetrain, and once someone wanted the trans, began the project, pulled the stock parts, and have sold almost all of the un-needed parts. As of today, the engine is in, mostly plumbed, engine bay wiring is complete, and rear suspension and cradle are out. Next up is pulling the gas tank, and swapping the fuel pump, and ordering the -6 line to make the new lines up. One simple task that turned into a lot of work was the re-rout for the heater core. I started out copying the V8R kit, using AN bulkhead fittings and hose, but found that the 90 deg. sweeps took up too much space to allow the heater core assembly, and AC box to fit back in the stock locations. I ended up moving the firewall holes farther out to the pass. side, and going with brass pipe fittings, which are much flatter, and allowed everything to clear. I like to put a slight flare on tubing, for hose sealing, but don't have the tools for rolling a bead on small dia. tube. Slipping the right size socket in the tube, and thunking it a few times create's a good flare. I used the Gates hose, part # 28469 to exit the core, sweep around behind the core, and mate up with the brass firewall fittings. It also seemed easier to adapt the engine side line that is 3/4in. down to 5/8's right at the engine, rather than on the core side of the car. I cut the Camaro heater tube assembly pretty close to the block, and re-welded a factory 5/8's end back on, so everything would be 5/8's hose, and that ended up being a lot easier to work with.

i agree that you will probably keep this car a long time. they are most excellent with the lfx. btw, that lotus is a beauty.

The build info on your car was super helpful; is it all set and running well now? The Lotus was a lot of fun to make, but the seat is so far back, it was like driving an old motorboat, I was pretty much sitting on the diff.

everything is solved on our car now except the clutch. waiting till spring to plumb the air conditioning. we have all the parts for that but we're stepping away for a bit to put a turbocharger on my younger son's 94, plus it's winter haha.

I'm installing all the AC bits, but it will be a low priority here in Mi. Like you, I will somehow have to make the lines, and suspect some of the wiring will be missing, what with the engine harness blending into the chassis harness being removed when the stock ECU was pulled. I look forward to hearing how you do it. I am using a stock clutch, so hope that will avoid some of the problems you are having with the clutch. I'm wondering how easy it will be to bleed an upside down bleeder?

I really do need to make that wiring write up - I had to make a few modifications to get the A/C added in.

I had complained a lot about bleeding the clutch in our thread - but most of that griping was due to the spring that escaped the hub. I made a lot more noise about it than was really necessary - trying to reverse-bleed, gravity bleed, vacuum bleed - when after all it was the clutch disc that was kaput. Using a mighty-vac helps speed up the slave bleed since there's quite a bit of volume to fill, but once it's primed bleeding is straightforward. Bleed nipple is still pointed downward though?

And that lotus is gorgeous.

Oh - and this might be useful for uncoiling AN6 line - grab some closet door rollers, put them on a piece of angle iron, chuck it into a vise, run the tube back and forth - quick and dirty straightener. Added the nuts at the bottom to keep the rollers parallel in the vise because I drilled the holes too far inside.

https://cimg8.ibsrv.net/gimg/www.mia...3c4222f2bc.jpg

As other's have noted, some of the alternator's have the battery lug very close to the V8R's engine cradle. Rather than try and re-clock the alternator,(and have springs and bits fly all over the garage), I took a little slice out of the top of the cradle; this opened up a comfortable clearance, and doesn't affect strength. I also decided to trim the frame flange back all along the inside edge of the engine bay. You can retain a 1/8in. or so of the 90 deg. flange on top of the main frame rails, and slice off almost 1/2in. per side, and weld up the seam while doing the corner clearance mods. It opens up the bay, and does not affect strength, and any clearance helps get the engine in. As I don't have a lift, it seemed easier to raise up the car, and slide the drivetrain in from below. I'd made a box with casters years ago for moving engines around, and that worked fine. The hope was to one-time the engine, and after studying the photo's of other guy's builds, the cutting, and welding up worked out fine, and so far, it 's still in the car.

I'm curious about that notch on the frame you made since I didn't have to do that. My car is 99. When I get back home I want to take a closer look at how much clearance I have. On my rear firewall I added a notch to add additional clearance to the rear of the engine but not sure I would have done that after realizing I had to modify the pedal bracket assy and steering column mount to get the whole thing to work right.

The cable I'm using for the battery is the original GM (2013 Camaro). From the alternator it goes to fuse box, but the direct connection to the battery goes via the starter on the driver side.

I'v seen two different hot lug locations on LFX alternators, and the one's like mine are right up against the V8R frame. Even with the notch, I have only a 1/16in. or so clearance, but is was easy to do. I ended up shortening, and using the stock Miata alt. pos. cable that feeds into the fuse block.

After thinking a bit, I remembered that when V8R sent me the engine kit, the small stand off spacers, (the pair of 3.8's, and 1/2in. spacers on each motor mount plate) were missing from my engine plates, not knowing this, when I trial mounted the engine to the cradle it twisted the engine, and held the alternator tight to the frame. I fixed that with the notch, but when installing the drivetrain, it would not fit the bolt holes in the chassis, and the tranny was way off center. After looking at Ryan's install photo's, I figured out I had some missing bits, and contacted Shandelle, who sent me the missing spacers. With those installed, the drivetrain un-twisted, and all was well. Still, the alternator/cradle fit is very close, and I'm glad I added the clearance in that spot.

Clearance for the HPFP I assume? How much did you add? Any pics?

The Firewall was recessed about 1.75 inches. It did not have to be that far down I think. At the time I though it did need to be that big. In the end it just created problems with the pedal assy and steering column. I got it to work, but it took a while to get all to fit correctly again. After some seam sealer, Lizard Skin and paint it came out looking nice anyway.




Attachment 219140

sorry having trouble with the pics

Did either of you guy's end up having working AC? If so, I'll be interested in how the lines were made, and if any additional under dash wiring was needed. I have the compressor with the engine, and the stock hard lines on the pass side of the engine fit fine, but will need to make the two compressor lines. I have the AC relay sending "Pos" to the V8R harness, but am wary of the wiring circuits eliminated when the engine harness / PCM were removed. Seems like the PCM wanted to see some signals from the AC in order for it to run.

Thanks for the pics Cujoel, it does look good with the 'skin' and paint!

Tomrev: I want to retain a/c in my car so this information would be helpful to me as well.

Besides the AC clutch signal and ground I know there is a high pressure signal as well which is typical of an AC system. I don't think there is a low pressure, but I'll double check when I get back home. I have both the camaro manuals and the miata manual for references.

I was happy to see the pair of upper stock lines will still fit, with a slight bit of bending. Pretty sure the smaller line has the high pre. sender on it, and my chassis harness clips to that. I'm expecting some wiring that originally went thru the large blue harness clip, under the dash carries this signal to the now gone stock PCM, so something may be necessary there to get it working. That will be next year; for now having her as a runner is the idea. It's rarely hot enough in Mi. to ever need it, I just want to have it once I can figure it out. Photo of the stock lines, and the blue harness that worries me.

I'm fairly confident our A/C works electrically (haven't charged it yet), though with the tighter constrains of the NA engine bay we needed to get a little bit more creative. We chopped the hard lines, welded new fittings on, had custom hoses made.

So - quick breakdown of the two systems (NA specific here) - and this is widely true of most automotive A/C -

When you press the A/C switch it goes to ground. This signal then tells the ECM that A/C wants to be turned on. The ECM checks 2 things - if you're not flooring it (by reading the TPS, avoiding power loss) and if you're low enough revs (to not overspin the compressor / causing belt slip). If it passes those two checks it goes first to the evap core temp thermoswitch. It's the two spade connectors underneath the dash in the evap core box. Normally it passes right through this - unless the core is iced up (at which point it breaks the connection). Passing this, it runs through the pressure side sensor / switch. It's a 3 position switch - it needs to see more than 30psi but less than 430psi to pass. Relay switches on and power is dumped real close to the compressor clutch, but not quite there yet. First it goes to the high side pressure switch that's mounted on the compressor itself, and then to the clutch.

Oh - and somewhere in there, the radiator fan is turned on without as much logic applied.

The Camaro side is virtually identical - except it uses a 0-5v sensor that allows the ECM to read the pressure instead of the switch, is commanded by the body module instead of a switch to activate the relay. I've read about some people using this input to read/log wideband O2's.

In ours I've wired it to bypass the ECM requirement - which means dumb things might happen, like belt squeal as we floor it. Just need to be mindfull and hit the button before you thrash it. But the thermoswitch and pressure switch are still in the loop. I might play more with the can bus to see if I can get it working to put the ECM back in the loop, but that's going to be a springtime project most likely.