1987 RX7 LS1 Swap

As some of you may recall, my 98 Z28 Camaro was totalled back around the beginning of November when a Transit Connect pulled out right in front of me coming home from work. Fortunately, both of us were OK, however I knew immediately the Crammit was mortally wounded. The good bits were mostly spared, so I wasn't even off of the roadside and into the ambulance yet by the time I was dreaming up potential LS swap projects. Lemonade out of lemons, right? So after some feverishly conducted research and some hearty debate on the forum, I narrowed the potential candidates down to either an OBDI e36 chassis BMW or an FC RX7. It was around this time that GRMer wvumtnbkr posted a supposedly rust free 87 RX7 with running issues for sale in the $2017 classifieds, and located just across the state, no less. Arrangements were made to see the car shortly after Christmas, and it did indeed live up to its billing. A deal was soon struck for the iconic rotary sports car, sans it's trademark engine. And today the time finally came to relocate the old Mazda to its new home. Here we are fuelling up for the return trip, shortly after executing the title transfer (at a former strip club .)

 And after a pleasantly uneventful journey, we arrived home. More pics:

 Even without a motor, this sticker to be worth a solid chunk of HP

 You may have noticed the extra passenger seat in the above pic of the interior. Negotiated into the deal were also a pair of TII seats and a set of adjustable dampers and Racing Beat springs.

 Overall, it's a very solid car. Decent paint, straight body aside from a couple dents and dings here and there, and, most importantly, remarkably rust free. This will be my first engine swap, and really my first dedicated "build" on any car. The car will see auto x and hopefully some track days as well, perhaps even ultimately progressing into time trials (we shall see, that's a long ways off for now.) Not building to any particular class (Emod I guess for auto x, though it won't be remotely near the limit of the rules), rather just building what I want - a light, powerful, good handling, and responsive sports car. Won't be full on challenge budget, but certainly not a 'no expenses spared' build either. That's it for now. I'll post more details on my exact plans later and get started on prepping the motor very soon. Looking forward to this one! Big thanks as well to the gracious Mr. Wvu for his hospitality and assistance!

Very cool build! I've owned 2 FCs with LS motors in them and they're a blast! Let's see some pictures of that garage too. Looks nice!

I look forward to watching your build.

Watching with interest. Hoping this will be the encouragement I need to get my LS-powered 944 going.

I can't wait to see what this car is like with torque!

If you need any other rx7 specific parts or have any questions about stuff on that particular car, just shoot me a text.

P.s. the wires on the floor by the drivers door were from a gauge that is no longer in the car. I believe one side in the bundle is hooked to power and 1 is hooked to ground.

Having never done an engine swap myself I look forward to seeing how this progresses for you. On another note I bought an LT1 RX7 in my younger days and it was awesome. The finished project will be worth the time.

Im excited to watch this one. Always wanted to swap an rx7.

Thanks for the well wishes guys! I'm sure it's going to be a challenging and frustrating process at times, but I'm really looking forward to the results, in terms of the car as well as a skill building exercise.

I made some meager progress today and pressure washed the engine bay and donor drivetrain. Didn't really have time for much else, as my XJ needed some attention and we had dinner plans with SWMBO's sister and BIL. I would post pics, but Photobucket is being uncooperative at the moment.

I have been having a lot of problems with photobucket lately too. It really pisses me off.

Does anyone know of an alternative to Photobucket?

In reply to YoloRX7:

I use imgur for my limited hosting needs, despite also having a photobucket account.

Yea I really need an alternative for photo hosting, should probably set of a Flikr or Imgur account before I get too far into this build. Photobucket is terrible anymore, more/more obnoxious ads than a sketchy pron site and issues galore.

I have been using my chumpcar build thread and hotlinking all the pics....

Imgur and photobucket keep locking up both of my work computers...

After being diverted for several days unsuccessfully trying to repair my Cherokee, I finally got a bit of time to mess with the LS again tonight. Engine was separated from the k member and transmission, pulled some accessories off, and that's about it. Obligatory pic: 

I'm not sure how I missed the start of this, but I'm in. Looking forward to watching you sort through all the details that it takes to make this work.

Nice! I can't wait to see this thing run again!

It has already had 3 different engines in it!

In reply to wvumtnbkr:

You definitely have to drive it once the LS is in!

Ok, so while I'm on lunch break, a bit more about my tentative build plans.

Motor: Like I said, this is the very same LS1 that powered my Camaro for 109K miles and which has been in my possession since 72K. By all indications, it's in great shape and has never given me trouble. Had an oil sample tested with Blackstone after I pulled it and they seem to agree it is indeed in very good health.

As such, it's pretty much gonna be left alone. Going to do plugs and wires, install an Improved Racing oil pan baffle (tomorrow's project, most likely), and call it a day. Ain't broke, don't fix it. I did toy around with the idea of tossing a mild cam in, but really this thing made plenty of power in the Crammit so I don't see the immediate need for more in a car that's going to weigh ~7-800 lbs less. Maybe down the road at some point...

For mounting, I will be using the Ronin deluxe FC swap kit. I wanted to keep the fabrication to a relative minimum for sake of expediency, hence why I chose to go with a kit. Cost isn't too bad at a bit under $600. I decided to go with Ronin because the trans mount is supposed to make exhaust routing much easier vs the JagsThatRun kit, and Hinson seems to have a bit of a suspect reputation when it comes to quality. Kit is (hopefully) on its way.

Drivetrain: Again, the T56 is a known quantity. It's in pretty good shape, aside from popping out of 3rd every once in a blue moon (bent forks I guess?), but again I think I'm just gonna leave well enough alone for now. I think I am going to put an LS7 clutch in, just because it's apart now and I kinda doubt the clutch has ever been replaced, but that still remains to be seen. I'll be adapting a Wilwood 7/8 master cylinder for clutch actuation and run a remote bleeder as well.

One of the beautiful things about this swap is the positioning of the engine and trans allows for the use of an off the shelf driveshaft out of a C4 Corvette. Mates up to the transmission and the length (allegedly) works out perfectly. I'll need to order the proper flange to mate the rear u joint to the diff (have the part number at home) and a conversion U joint (3150 to 7260 ? IIRC).

Per Mr. WVU, the car was originally an automatic and still retains the original diff, which means a clutch type LSD with a 3.90 ratio. Conventional wisdom seems to be that the N/A FC diff is a bit questionable in its ability to withstand the torque of the LS, however my plan is to run it for now and upgrade if/when it breaks. The ratio should actually be about perfect and the ring gear is really only 5/8" smaller IIRC than the 10 bolt that originally came behind the motor. With less weight and less tire to deal with, maybe it will hold up OK.

Exhaust: Planning to use JTR's long tube headers for the LS/FC application. A bit spendy, but not ridiculous, and should make for a nice power bump and glorious noises. I'll likely build the 2.5" true dual exhaust myself, which will include cats, an x-pipe, and probably some Magnaflows (like the way they sound on the LS.)

Wiring: I'll be attempting to modify the harness myself. We'll see how this goes...

Accessories/Misc: Using all of the Crammit accessories and bracketry. Unsure yet if I'll be retaining AC and power steering. Seems like finding a local hose shop might be my best source for mating the GM and Mazda components, if I do decide to keep either.

As for fuel, the car has already had the tank cleaned and coated, Walbro pump installed, and (IIRC) new lines run up to the engine bay. Perfect. The only minor hassle here is that the Mazda uses a return style system, while the LS has a return-less fuel rail. Not a problem, though, as certain year C5 Vettes had a filter/regulator combo with a return line to the tank and a single line to the fuel rail. ~$70 part and it should work perfectly.

Cooling I haven't entirely figured out yet. JTR offers a kit based around I think a C4 Vette radiator, but I think I can roll my own for a good bit cheaper and not too much effort. 27x19 seems to be the common radiator size and I think both the Camaro and the RX7 radiator have both the inlet and outlet on the passenger side, so hopefully I can just bastardize the hoses I've got. I've seen a plethora of different junkyard electric fan setups used, so once I have the radiator picked and exact measurements I'll do some shopping at the U Pull.

I think that about does it as far as getting the engine in and running, though I'm sure there's some stuff I'm glossing over and/or haven't thought of yet.

Once it's up and running, I'll focus on doing a suspension refresh using the shocks and springs I got with the car, all new bushings, eliminate the passive rear steer, sway bars, ect. After that, it's fun time

Definitely throw a cam in it. I made 380rwhp on my LS1 with stock 241 heads with a very mild cam, long tube headers and an exhaust.

In reply to docwyte:

Oh I'm well aware of what even smile can will do in these motors. That's kind of the problem though, it's a question of how much is too much.

Which cam are you running? I was thinking along the lines of a TSP 224r, or even a 220 or milder if anything. What about valve springs? Pushrods? You know, just in case...

Got the engine mounted on my new stand last night, then set about removing the rest of the harness. Took the exhaust manifolds offense well. Now that I'm staring at this like of wires, the task of adapting the harness is beginning to seem a bit daunting.

 Today I started off doing some more cleaning, as the pressure washer must not have reached the block very well. Several cans of degreaser later, I was left with this. Still far from perfect, but at least somewhat presentable and clean enough to work on.

 Next, I set about removing the oil pan to install the Improved Racing baffle. Pretty clean under there.

 The pan itself had just a minimal bit of sludge at the bottom and a couple pieces of metal in it, but I don't think it's anything to be concerned about (I hope.)

 Removed the stock baffle, cleaned it out thoroughly with brake cleaner, and set the Improved Racing baffle in place. Fitment was spot on and build quality seems excellent. Very nice piece.

 Got the baffle bolted in and changed the o ring on the oil pickup tube. I would have put the pan back on, but my RTV seems to have run away, so I stopped there. I'll pick some up tomorrow, along with fresh plugs, and we'll pick up from there...

I think it was a 230/234 cam with matching pushrods and a set of dual valve springs.

Initially I had a 228/228 cam but it was way to flat, I only made 337rwhp with it. Literally added over 40rwhp with just swapping the cam...

You know how some days you really don't feel like working on anything, but you make yourself do it anyways so you don't feel lazy? Well, sometimes that means you should just stay the hell out of the garage. Went to put the oil pan back on with the new gasket, not realizing a piece of the old gasket was still in place.

 That piece is incorporated into the rest of the new gasket, so it ended up double stacked here...

 The result of which was a sickening snap when I went to torque the pan down. berkeley! 

 Looks like a new pan is in the neighborhood of $250, which makes the idea of a JB Weld repair awfully tempting. I suppose I could also take it in to work and bribe someone to tig it back together for me, but I'm seriously doubtful that can be done to a sufficient level of penetration (it's easily 3/8"+ thick) without warping the piss out of it. Might have to bite the bullet on a new pan After this I'm done for the day. At this rate, I'll surely snap a plug off in the head if I touch them.

berkeley!

At least try to tig it. Bevel it and take a few passes.

Yea no harm in trying at least.

I'm just so pissed I did that. Such a stupid, careless, yet expensive mistake.

I feel bad for you... those are the worst mistakes to make. Hopefully you can repair it!