1987 RX7 LS1 Swap

Sick!

Any chance you want to swap the 3.9 rearend for a 4.1?

Let me know if you swap rearends. I'd be interested in the NA 3.9 LSD rear that is in the car.

You're making this look easy and giving me bad ideas of LS-swapping something.

Note that I have the fabrication skills of a slightly-retarded parrot.

In reply to wvumtnbkr:

I'll let you know if I ever swap it for a T2 or Ford 8.8, but I'm probably sticking with the 3.9 rear for at least a good while. The ratio should actually work pretty well I think.

In reply to Sky_Render:

Thanks, it doesn't always feel that way! I spend a lot of time staring at the car, sipping a beer, going 'How the berkeley do I do THAT?' that gets glossed over. And I feel like progress is a bit slow, especially watching Rob's build. But it honestly hasn't been too bad so far, considering this is my first time. I'm glad I picked the FC chassis, as it is a really well developed swap by now with most of the major wrinkles ironed out.

So one step forward and two steps back this weekend. My headers came in on Wednesday and I was eager to get those installed. Unfortunately, I concluded from looking at pics of other guys installs online that I probably hadn't bashed the firewall sufficiently for clearance.

So out came the motor again on Saturday so I could beat on the firewall some more. "While I was in there" I also wrapped the fuel and clutch lines in some heat insulation, secured the fuel lines to the body, and attached the non-traction control f body throttle cable to the firewall, which took some trimming of the plastic grommet.

Today I managed the get the motor back in and attempted to fit the headers. Getting the motor out and back in by myself actually wasn't too bad, but trying to get the headers in sucked. The driver's side went in OK, but the brake booster is probably going to have to come off to get the last bolt. One of the primaries also just ever so slightly touches the firewall in one spot. Like seriously one more light tap with the hammer and it would have been fine. So I guess that will have to come back off, but I should be OK leaving the motor in place.

The passenger side was deceptively much more difficult. I can't just can't seem to shake the header into place. I have the front end of the car jacked way the hell up and the firewall has been generously massaged, but the header keeps hanging up between the hump on the bellhousing for the starter and a tab on the subframe. Like I can get the flange up high enough with it oriented vertically, I just can't rotate it so the collector is horizontal. Very frustrating. I'm hoping this is one of those things where I come back to it tomorrow and it goes right in, so I left it alone for the night.

So lots of work without gaining a whole lot of ground. It does feel good to hopefully have the motor in for the last time at least.

Furious_E wrote: So one step forward and two steps back this weekend. My headers came in on Wednesday and I was eager to get those installed. Unfortunately, I concluded from looking at pics of other guys installs online that I probably hadn't bashed the firewall sufficiently for clearance. So out came the motor again on Saturday so I could beat on the firewall some more. "While I was in there" I also wrapped the fuel and clutch lines in some heat insulation, secured the fuel lines to the body, and attached the non-traction control f body throttle cable to the firewall, which took some trimming of the plastic grommet. Today I managed the get the motor back in and attempted to fit the headers. Getting the motor out and back in by myself actually wasn't too bad, but trying to get the headers in sucked. The driver's side went in OK, but the brake booster is probably going to have to come off to get the last bolt. One of the primaries also just ever so slightly touches the firewall in one spot. Like seriously one more light tap with the hammer and it would have been fine. So I guess that will have to come back off, but I should be OK leaving the motor in place. The passenger side was deceptively much more difficult. I can't just can't seem to shake the header into place. I have the front end of the car jacked way the hell up and the firewall has been generously massaged, but the header keeps hanging up between the hump on the bellhousing for the starter and a tab on the subframe. Like I can get the flange up high enough with it oriented vertically, I just can't rotate it so the collector is horizontal. Very frustrating. I'm hoping this is one of those things where I come back to it tomorrow and it goes right in, so I left it alone for the night. So lots of work without gaining a whole lot of ground. It does feel good to hopefully have the motor in for the last time at least.

Awesome!

You can probably just cut that tab off...

What if you unbolted the engine and lifted it like an inch? Would that get the header in place?

Did you pressure test the heater core? I am worried because of the antifreeze on the carpet and I never had any antifreeze in the interior of the car...

It's a bitch to do that job....

In reply to wvumtnbkr:

That's my plan, cut the tab and see if that gives me enough room, if not, then jacking the engine up a bit definitely should.

I have been doing my best to ignore the heater core for the time being...

You can just bypass the heater core until it gets cold anyway....

What does your list to finish look like? any major items left?

I was just thinking, you towed that car on an open trailer with no shifter in the shifter hole. Could it be gunk and stuff blowing UP through the shifter hole that got the carpet wet? I don't think it rained that day (that I can recall) but I did just take out the engine that was in there. I am sure there was liquids in the engine bay...

I don't think it rained the day I picked it up, at least until after it was back and unloaded. Or maybe it just briefly did, I remember the weather being weird that day.

I did, however, pressure wash the car shortly after picking it up, so I could have easily blown water in the shifter opening or something. I'm about 50/50 right now as to whether it's that or the heater core. The mystery liquid didn't really have a smell, so it could have easily been plain old water that got turned into nasty carpet tea. It just happened to be a similar color to manky old coolant and seemed slow to evaporate. Either way, I'm just going to hope for the best until it's up and running and then I'll find out.

The official running list is on a piece of cardboard in my garage, but as best I can remember at the moment:

-Finish heater hoses

-Coolant hoses (thought I could get away with using the Camaro pieces, but no dice, both are wrong diameter on one end.)

-*WIRING*

-Driveshaft

-Battery mount/finish battery wiring (need to pick a battery first)

-Probably need to extend throttle pedal for sufficient cable travel

-*Build exhaust*

-Bleed clutch

-Enlarge shifter opening/install shifter

Really not too far off from first start, actually

Got the headers in tonight! Driver's came out for additional clearancing and went back in without much drama. I cut the tab off the passenger side and still no dice over there. I was just about to pack it in for the night and resort to hoisting the engine tomorrow when I decided to jack it up just a bit more. I don't know if it was that extra inch or two of clearance or if I just found the sweet spot, but they went in pretty much right after that.

 Not the best pics, but trust me they look sexy

That engine fits sooo well in that chassis. So far back and so low!

It's ridiculous how well the V8 fits. I'm not exaggerating when I say it fits better than in the Camaro. I can actually reach all of the sparkplugs!

Made some meager progress over the last few weeks. I'll try to post pics later tonight.

Heater hoses are ready to go. Used two p/n 63244 little squiggly bent hoses, trimmed accordingly, to get up and out from behind the intake manifold and heads. Clearance is TIGHT back there and it looks like I am going to have to do some replumbing of the oil pressure sender, as it, one of the heater hoses, and the brake booster vacuum line are all fighting over the same piece of real estate. Those little guys run through a couple of plastic elbows and fittings into a pair of long, L shaped hoses (63824 & 63107), down the passenger side of the bay to the water pump.

I've also got a functioning throttle peddle! Had to order a throttle cable for a non cruise/traction control f body and trimmed the grommet to fit the Mazda sized hole in the firewall while the engine was back out. An initial test revealed that, as expected, peddle travel was insufficient to completely open the throttle. So I cut the peddle and welded in a ~1" extension, which then had to be bent to just the right angle through extensive trial and error. Side rant: At 6'3", there are few things I enjoy less than contorting my body for under dash work in a space made for Japanese sized feet.

Let's see, what else...

Cut the shifter opening. Gonna pick up some transmission fluid and get the shifter on there tonight most likely. Should bleed the clutch this week as well, if I can recruit a helper, and make sure that's all functioning as expected.

The next big step is wiring. I decided to suck it up and cough up the $300 to have Ronin modify the harness for me, so that ships out today. Had been planning on doing the harness mods myself, but I hate wiring and really didn't want to screw anything up.

While I'm waiting on the harness to return, I'll finish running the battery cables and cooling fan wiring. I've been debating whether or not I want to add a kill switch for the battery. I'd like to run this sucker down a drag strip at least once and think I'd need the switch for NHRA legality, seeing as the battery is being relocated, but at the same time that's not a huge priority and I'm not sure I want to cut the body anywhere to mount it. Or where I'd even put it for that matter.

Quick update, just to get things back up to speed. I'm still waiting on the wiring harness to return from it's vacation in California, but making slow and steady progress in the meantime. Part numbers are posted in part for my own future reference Highlights:

-Replumbed the oil pressure sender for remote mounting using an oil pressure gauge plumbing kit

-Radiator hoses pretty much done, used 61047 and 61176 to make the lower, and the stock Camaro upper hose and a 71516 to make the upper. Just waiting on the hose coupler with steam vent fitting to finish the upper hose, lower is done.

-Battery cables are mostly complete, just need a negative to the yet to be ordered battery. Decided to skip the cutoff switch and ran a 2 gauge cable from the 200A breaker up under the passenger seat, through a grommet in the firewall to a terminal post on the passenger side frame rail in the engine bay. From there, 2 gauge cable branches to the starter and alternator and 8 gauge runs from the alternator to the front terminal on the Mazda fuse block. I think that's right, but I am still not sure what, if anything, the terminal on the back side needs to run to.

-Fan is wired through the Volvo relay, thinking it should work OK running the single speed Taurus fan with just one of the input/output sets connected. Power feeds through a fuse straight from that terminal post.

-Intake is assembled and almost ready to go on, waiting on a 90 degree coupler and still have the manifold off so I can access sensors behind it once the harness returns. 90 degree 4" coupler runs off the TB towards the passenger side, into piece of tubing, through a 4>3.5 reducer into the MAF, and a K&N KNN-RU-3130 filter.

There's a bunch of other little E36 M3 too that I'm forgetting or isn't worth mentioning. Getting really close to firing it up, though! Pretty much just have to wire it and flash the ECU to make it play nice in it's new home.

Adding some random pictures...

 Here's the intake, just waiting on the 11/16 hole saw I ordered to get here to drill a hole for the IAT sensor.

 Current state of the engine bay. Nice closeup of my fingers there too (oops.)

 Today's project, sorting this mess out. Got a little bit of a start last night.

I also spent some time working on the instrument cluster last night. The RX7 comes equipped with a cable driven speedo, whereas the T56 has no provisions for a mechanical speedo drive. There are doohickeys out there to convert the electronic speed signal from the PCM to a mechanical output, but the grassroots solution is to swap a speedometer from a 3rd Gen Integra into the cluster.

 Here's what we're working with. You can see they're both similar in size and top out around 145mph.

 I unscrewed the gauge face from the Integra and reset the odometer.

 The cluster housing needed some trimming to fit, which I made quick work of with the Dremel.

 I popped the gauge face off of the RX7 speedometer as well and screwed that to the Integra guts. Even though the Acura face was attached in a completely different manner, there was still a set of holes there that lined up perfectly with the Mazda gauge face. Amazingly easy. 

 And here it is, looks almost stock. I'll paint the needle white to match. Thinking I'll attach it to the housing with some plastic rods trimmed to length, screwed to the gauge face at one end, and glued to the housing at the other.

That's incredibly cool about the Integra speedo! Do they have Mfr markings? Are they both Denso units that just happened to be electronic vs mechanical versions of the same basic design? I see a "YNS Inc" marking on the Mazda gauge face, but the googles don't tell me anything... Not that I'm about to do anything practical with the info, I'm just always fascinated by accidental compatibility between car parts.

In reply to Ransom:

It seems to be just a happy coincidence. Like you said, the Mazda is marked "YNS Inc", but the Acura unit is definitely a Denso. Lots of other differences too, they definitely do not look the same at all from the back side, the face just happens to bolt up.

Quick update: Very hot and sweaty weekend in the garage, but the good news is the wiring is now 95% complete. Just have to run the wire for the oil pressure gauge and hook up the reverse lights to the tranny. Oh, and fix the plug for the MAP sensor that I yanked the wires out of when pulling on the harness for more slack . Really wasn't bad though, probably spent more time figuring out how to route stuff than anything. Glad I spent the money to have Ronin do the hard parts.

I am going to be watching this build. I love LS swaps. And don't be discouraged about the time frame. The LS swap into my Corolla took me 2 1/2 years. And it had a SBC in it prior to that. You are flying on this build. And as for the battery kill switch, I personally would only wire it up just to kill the motor and fuel pump. They are only looking to hear the motor die when they use that switch. I am not familiar with the rear end that is in that car but I would thing a solid axle swap is going to be in the future. I used an axle from a 96' Explorer when I was building my Corolla. 8.8 with 3.73 and factory 31 spline axles. I had to cut 7" out of the total length to get it to fit though. 4.10 was an option, but 26" tires and 4.10 @ 60mph was a little much. I have heard 28's will fit.

Love the build. And I will be watching.

There is actually a mostly bolt in kit to use an 8.8 IRS out of an explorer.

There is also the option of the Turbo rear diff and axles. They put up to most any abuse (with the exception of sticky tires and repeated drag launches).

In reply to DEATHTRAP:

Thanks for the words of encouragement! I guess these things never go fast enough for one's own liking. It's just killing me since I haven't auto xed in a year plus now due to the Camaro's demise and people poorly scheduling their weddings last summer. I'm dying to drive something in anger and my Jeep isn't really good at that

I think Granny's actually offers a solid axle swap kit to put the 8.8 in one, but I ain't puttin no stick axle in this thing. The 8.8 IRS swap would be great, strong as hell and gearing options galore, but that's also probably a $2k+ ordeal all said and done. I think the TII diff is going to be my ultimate solution for a rear, but the plan is take make the N/A diff last as long as possible first.

In the axle assembly itself, I think I had about $700-#800 in it total. Most of which was the custom length Moser axles. I think it cost me about $120ish to pull it from a salvage yard. I used the factory Toyota brackets too. Now the IRS stuff will probably be a little trickier. But if an IRS center section will bolt in, that sounds a little easier and hardly any fab work. And yes, thinks don't go as planned on some of these projects. I did months of fab and planning before I pulled my motor. Thought it would be only about 6 weeks. Then the opportunity to make more changes presented itself again and again.

It runs!!!! It berkeleying runs!!!! Bahahaha!

Played around in HPTuners for a couple of evenings last week deleting all the relevant fault codes and such and had a tune ready to go in. Thought it would be a matter of just a couple hours yesterday draining the gas, putting fresh gas in, loading the tune, and bleeding the clutch, but instead spent most of my working time this weekend just trying to bleed the stupid clutch. Finally broke down and bought a Mittyvac today, which did the trick (should have bought one years ago.)

Then I loaded the tune aaand...nothing. Wasn't getting fuel pressure. Some quick diagnosis revealed that I had forgotten the stupid fuse for the fuel pump, so I threw that in and it fired right Up! So psyched!

Took a video, so I'll have to figure out where to host that and how to post it. I guess the great Photoberkit fiasco has ruined the rest of this build thread as well, which is why I haven't bothered posting updates recently, so I'll have to correct that as well eventually.

Still lots of details to iron out before it's 100% roadworthy, but I've now cleared the biggest hurdle. Time to go consume some celebratory beverages!

It lives!!!

I use Imgur now to update my threads.

Great job getting it running!