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'86 rx7 fc3s base model
4.8l iron block ls (lr4)
nissan 300zx z32 na 5 speed
figured i'd make an account here and start a build thread a year and a half into the build lol
i mainly want to document what i've learned and have figured out for myself and anyone else looking for info on this kind of swap.
bought this absolute nugget fall '24 for $1300
its an automatic base model fc that sat in a barn for over 20 years. it was in a wreck in like 2002, was repaired but never driven again. the previous owner passed away before getting it back on the road, and now some idiot bought it to put a v8 and 5 speed in and drift it
the facebook ad claimed it ran and drove. the lie detector determined that was a lie. so i talked them down a bit on their price and started this journey. i had never done this level of work to a car before, i had pulled subaru engines to do head gaskets and a clutch, i'd done wheel bearings, brakes, oil changes, lowering springs, a few cosmetic things here and there, but nothing like what i was planning to do to this poor old mazda...
got it home and ran a compression test on the 13b and it had 80-90psi in each rotor housing, put it up on facebook with pictures of the comp test and sold it for $1000 within a day or two. and thats when the molestation began
i'll keep updating this thread and get it all caught up
i found a 4.8l ls for $350 half a mile away and picked it up and a z32 5 speed less than 10 miles away for $250. i dont really care about 5.3 vs 4.8 vs 6.0 and all that, the 4.8l is still a pretty decent jump in power from the na 13b and i'm sure i'll be more than happy lol got the engine on a stand, started breaking it down, cleaning it, and getting it ready for a few goodies.
got a tsp chopacobra nsr cam, seals, weiand baffled oil pan [part# WND-5045WND], camaro windage tray and water pump, and ict billet swap kit called "LS Truck - Alternator & Belt Tensioner Relocation Bracket Turbo LSX (uses LS1 WP)" [part# 551573LS0WP-3]. i used two 5/16 wooden dowels to hold the lifters up while swapping the cam and it worked amazingly.
picked up s5 convertible taillights, brakes, and 5 lug swap from a somewhat local guy that parts out rx7s
the s5 vert taillights fit no problem, its been a while since i installed them but im pretty sure the only issue i had was that some of the bolt holes dont line up for the plastic that holds your license plate and a couple broke getting the old taillights out. i still need to back and take care of that.
kept working on cleaning the engine bay and taking care of any rust i came across with sandpaper and a wire wheel, also used some rustoleum rust dissolver in harder to reach spots. then i cut out the radiator supports on the left and right to make more room for the v8 and radiator setup.
i had plenty of rust dissolve left over so i soaked all the rusty hardware, brackets, and hood latch and it worked great, wish i would have taken a "before" picture lol
kept sanding and laying down primer, prepping for paint before it gets too cold. i didn't want to have to wait for spring and i wanted to get the engine off the stand and in the engine bay.
decided to go black with some pink and red flake for the engine bay. got a cheap amazon spray gun, bought flake from didspade, and picked up a quart of black and a quart of clear from autozone.
i used to work in the paint department at a major auto factory, so i know my way around a spray gun, tho i mostly just had to spot spray primer on exposed metal and hadn't done something like this before. still, this came out exactly how i wanted, tho a little bit of orange peel. i couldn't wet sand because i used colored flake in the clear but im happy with it.
bought the ronin ls swap kit, g force ls to z32 trans adapter plate and flywheel, and a z32 stage 3 n/a action clutch, installed them and got the engine in with the help of an amazon ls lift plate. the ronin engine mounts were easy to install and went right into the factory subframe.
winter came shortly after, and the car got put on the back burner for most of '25 and i regret that i didn't do a whole lot for the next year but it is what it is. we keep moving.
decided to go with aces efi jackpot ecu and top end kit. i was going to just use the factory chevy ecu, flash it and get a tune, but looking at piecing everything together it was going to cost more than the aces kit unless i got lucky and found some crazy deals or went with super cheap/used stuff. it came with standalone ecu, wiring harness, digital dash, intake manifold, throttle body, injectors, and fuel rails for $1200 and free shipping. kinda hard to beat if you ask me.
the aces kit had been sitting around in my house for a couple months, finally got around to installing the intake, injectors, and fuel rails, but thats it.
(dec '25)
christmas rolled around and i got a thrash steering wheel, i had to lock in and get back to work on the fc
went to an auction looking to buy another fc (whats wrong with me?), got outbid but picked up some stock honda wheels for around $100. no idea what kind of honda they're off of but they're 17x8 and look pretty decent. i love 5 spoke and double 5 spoke wheels, so these will work until i get something nicer and use these as drift spares. picture is from google, they're the same exact wheels but i didnt save any pics of them before putting them up in the back of the garage.
i'm a hater of black wheels, so i plan on removing the paint and polishing them.
(feb '26)
got the cx racing fc ls swap radiator and a cheap intake (we'll see if i replace it or not, depends on how everything fits later on in the build). the cx radiator kit didn't come with any instructions and i struggled with the lower support more than i care to admit lol but we got there. the upper coolant pipe fit great, but the lower coolant pipe is like an inch and a half too tall. waiting on thermostat, thermostat housing, and pipe bead roller so i can shorted the lower pipe.
the car was originally an automatic, and one thing i wasn't excited to do was getting all upside down in the driver footwell and removing the fat brake pedal assembly and replacing it with the manual pedal assembly. the pedals had been sitting around for probably 6 or 7 months and i finally just did it. it was such a pain in the *** lol i had to wrestle the auto brake assemble out, but the manual pedal assembly went in way easier.
one thing i didn't think about was the clutch pedal push rod that connects the pedal to the clutch master cylinder.... the pedals i got didn't have it (missing part circled in red). i thought "no big deal, i should be able to find that online". nope. i couldn't find it used or new or any sort of universal one that i felt confident would work. so i did a lot of digging and found part numbers for each individual part that makes up the clutch pushrod, but mazda dealerships only had the fork part in stock (part# 0305-41-140). so i ordered it and decided that when it comes in, i'll just figure the rest out at a local hardware store armed with just the one part and a photo i luckily found of a fully assembled one with measurements (shoutout to the guy that took the photo, i dont remember where i found it, it was probably on here).
for reference if anyone needs it or i need it in the future:
got a lot done, was pretty motivated and weather was nicemost of the month
ordered a new brake master, so i decided to clean up and paint the gross old brake booster i have. wire wheeled and sanded all the rust and paint off and sprayed it black with a small hint of the pink and red flakes i used in the engine bay, along with the windshield cowl that barely had any factory paint left on it.
finally time to get the z32 trans in and bolted to the engine. i saw John Leedom's youtube video about his swap (the whole inspiration and a good amount of the blueprint for my swap and trans choice) that the t56 trans crossmember that comes with the ronin ls swap kit bolts straight to the z32 5 speed and works just fine since since the swap crossmember uses sandwich plates on the interior to hold it. prepped the transmission by replacing the things that should probably be replaced when using a facebook marketplace trans. oem nissan clutch slave, concept z performance upgraded heavy duty clutch fork kit that comes with a stronger clutch fork, chromoly pivot ball, fork boot, and throw out bearing. also got a shifter relocation kit from xcessive manufacturing (part# n-vg-sb-s) that moves the shifter forward 60mm and a z1 motorsports short throw shifter.
removing the gear selector was more annoying than i expected. the bottom right bolt is tough to get to because the gear selector bracket gets in the way and its under the center console trim around the shifter. i got out a swivel head ratcheting wrench and managed to get it.
some cutting and bashing was required to get the trans in. there was a hump on the inside of the trans tunnel on the driver side that needed violently removed, the shifter relocation bracket needed trimmed a little at the hips, and the shifter hole needed cut up in the lower left corner to fit the shifter up in it. i didnt get pictures of most of the carnage, but if you do this trans swap have a new cutoff wheel ready to rip, you'll see what gets in the way.
i didn't want to just leave that hole open, so i got some sheet metal and the rubber shifter boot from a 300zx and got to work. had to chop some of the trim off and i wont be able to put the arm rest back in, but thats fine. sadly tho, i had to give up the cable handbrake. i was planning on keeping it, but the trans swap said otherwise. the cable had been cut or it snapped in half before i bought the car. glad i didn't order a new handbrake cable already lol
got around to running the new aces engine harness through the firewall. i cannibalized the stock one for the grommet and the wiring for the windshield wipers in hopes i can figure out how to keep those later down the line. i used part of the old harness and taped it to the end of a pry bar, ran it through the firewall and then taped the new harness to the old wire, taped over all the connectors so they wouldn't snag, and pulled it through from the inside of the car into the engine bay. ran all the wires to the engine and the corresponding sensors. need to get an oil pressure sensor, fuel pressure sensor, and one more wideband and then the whole engine harness is hooked up. also, at some point i got a mooneyes dash cover, just haven't velcro'd it down yet, need to fix the giant dash crack above the gauge cluster first.
today i went to the hardware store, i took a few things with me for reference.
i needed:
-longer bolts for the lower radiator bracket. it uses the factory tow points up front and the factory bolts aren't long enough for both the radiator bracket and the tow plate and i wanted to keep both. plus the old ones were raggedy.
-longer bolts for the throttle body. i had gotten a throttle cable bracket that sandwiches between the throttle body and the intake manifold, but the hardware included with the intake wasn't long enough. the aces intake had no way of securing the throttle cable.
-the previously mentioned clutch pedal rod that was missing from my pedal assembly.
first two things were easy, just needed slightly longer bolts than the ones i walked into the hardware store with. but the clutch pedal rod took me a minute to figure out and piece together. i ended up with a m8 bolt that was 80mm long which threaded into the clutch pedal fork that i got from a mazda dealer, an m8 nut to for a lock nut, a 5/16 clevis pin that was way too long but had a bunch of holes in it so i could cut it down to size, and a retaining pin. got home and started cutting up the long m8 bolt. i ground the head down with a cutting wheel until it was the same diameter as the neck of the bolt, then got the clutch master out and kept shaving it down until it fit in the hole, not too tight and not too loose. it seems to have worked out great, but we'll see how it holds up once the car is running and driving.
one bit of info for anyone doing this z32 trans swap into an fc rx7 using the fc clutch master and not an aftermarket one: a nissan 300zx z32 clutch master and the mazda rx7 clutch master have the same thread and pitch for the clutch line, but im 99% sure the slaves are different threading. that means you can use a clutch hydraulic line for a z32 since you'll obviously be using the z32 slave with the z32 trans. i got the "Z1 One (Single) Piece Stainless Steel Clutch Line" from z1 motorsports. it goes from the master all the way to the slave cylinder. the banjo bolt threaded on perfectly to the fc clutch master. its a little long but that leaves plenty of choices for routing it however you want or need.
like i said before, the "Coolant Radiator Pipe Bracket Kit For 86-91 Mazda RX7 FC LS1 Engine" radiator, support, and piping kit from cx racing (part# BRK-RAD-RX7-FC-LS-KIT) came with a lower radiator pipe that was a bit too long. since the pipes are bead rolled at the ends, i ordered a cheap bead roller on amazon, and the thermostat and thermostat housing came in recently too. it was a nice day out so i got to work. got the measurement for how much needed cut off, rolled the end, and put it all together. the bead roller was super easy to use and it did a pretty good job. first picture is how much i had to cut off past the 45 degree bend, second pic is with the bead rolled end that i did.
i need to get some spal fans, a sheet of stainless to make a rad fan shroud, a coolant line to go from the steam vent tubing to the port below the upper rad pipe pressure cap thats pointing towards the engine, and a coolant overflow tank and the cooling system is DONE (probably lol)
