Recommissioning my 82 RX7

Minor update.

When I first got the car running, I was driving it without the passenger seat in place. After a while, my wife started asking when she could go for a ride. I stalled a bit explaining she needed to be available with my truck as a recovery plan, but eventually, I tossed the passenger seat in and took her along.

I was a bit overzealous though, and neglected to complete a repair of the seat slider catch on the passenger seat. So, her first ride consisted mainly of her attempting to brace herself and keep the seat from sliding forward or backward at every light and stop sign. This seemed to make it impossible for her to appreciate the awesomeness of riding in my beloved RX7 again for the first time in 15 yrs. 

I had bought these seats used and the previous owner had done a very hackish and ill conceived fix.. The mechanism has a wire torsion spring that keeps tension on the lever and keeps the latch in place. The latch is connected to the lever with a roll pin.

On the passenger seat, under previous ownership the roll pin had gone missing, and the PO had uninstalled the torsion spring and re-purposed it as bailing wire to replace the function of the roll pin. This was a partial fix, the seat would latch in place, it just might not stay latched as well as one would like.

I had removed the spring and straightened it, but neglected to re-install the spring or a roll pin.

So, out the seat came, and  I implemented a fix that is less of a hack and more functional. Unfortunately no before pics, but I straightened out the spring, and inserted the end of a nail to take the place of the missing roll pin. I plan to install an actual pin and paint the assembly once the seats come out for a new carpet install.

repaired latch on the right, unmolested drivers side version on the left. I ziptied the spring in place, because it wasn't completely back to original form, and I thought it might come loose. But really, I think it would have been fine.

Another not update but statement of intent. I learned that the Deal's Gap Rotary Rally is in a couple of weeks, and I'm planning to trailer the car up there for the event. Never been to one of these, but it sounds like almost 200 cars will be there, so I'm excited to check it out.

I have a multi item list of must do's and should do's, and a small pile of parts waiting for me once I get back from Easter holiday travel.

Ticking a few things off my list to get ready for the Deal's Gap trip.

Since the first start, the motor has been leaking a little coolant from behind the water pump housing. It would leak about a quart on my longest outings (~50 miles). I had been putting off taking care of it and just topping off before each drive. I got that taken care of this week. Not sure why it was leaking, but I cleaned up the mating surfaces and replaced the gasket, and all seems good now.

I also had been running without a coolant level sensor because the radiator I am using is an ebay aluminum direct replacement for the stock rad, but the mounting bung for the coolant sensor was 1/4" NPT instead of the oddball metric thread of the stock piece. It was a little hard to find a replacement searching on thread size, but I found one at a company called Hewitt Industries. Great service and I got it in two days from the west coast. With all the supply chain issues, I had asked in my order to call me if the part was on backorder. I got a call 5 minutes after ordering that the part was in stock and would ship that day. Works perfectly.

Another item checked off: Somehow over the years, I lost the transmission wiring harness for the car, and had up til now been without reverse lights. Set about fixing that recently, and pulled the switch from the trans and tested it...and it's bad, high resistance when the switch is made. Ordered a replacement (for $180, oof) and it looked just a wee bit different! Double checked my order, and this part is listed as fitting my trans. I was skeptical the ginormous new part would work because the plunger length isn't quite the same and wasn't sure it would thread in because the hex body is 30mm vs 24mm and it sits very close to the transmission case. But indeed it did fit and with a patch wire into the main harness connector, I had reverse lights. I bought some LED replacements that are supposed to be 300% brighter. You can see the new light on the left. Pic was taken in daylight, but it is indeed noticeably brighter and a much cooler color temp. No more backing out of my long driveway at night sticking my head out the open driver's door!

Next item was good to clear up but kind of a dumb mistake on my part. The top mount intercooler didn't really fit properly, not sitting level - the driver's side sitting too low, and unable to install the support bracket on that side. I had thought that I had bent the large bracket that holds the intercooler and other things and also serves as the front lifting eye for the engine. I thought I had bent it by lifting the engine without all the things bolted to it - namely the intake manifold which greatly stiffens the part. But it turns out that I had grabbed the wrong lower hose for the intercooler - I failed to notice that one of three similar hoses was actually about 3/4 inch longer on one leg. Unsurprisingly, with the correct hose, it's much better and the driver's side bracket now lines up great instead of being impossible to fit into place. With that sorted I can start to get the gasket installed that goes between the hood and IC

So, even though the new tires greatly improved the situation, the car had quite a lot of rattles, especially over rough pavement. So, I been trying to chase those down over the past few days. Still definitely not tight as a drum (or modern car), but much improved. Actually really good on smooth roads and highways. Pavement ripples and potholes definitely still bring out some lack of refinement.

Successes so far:

Add anti rattle clips to the rear brakes and caliper lube - cured a clicking sound that would go away under light brake pressure. Also, eliminated some groaning noises from the rear brakes under light braking at parking lot speeds. I didn't have the clips handy when I installed the brakes, so good to get that knocked out.

Add rubber tube around key areas of the metal fuel lines - The clips I'm using don't snug down the lines to the body in a couple of places, and there was a section of return line that wasn't very secure at all that was banging against another hard line. I think this one was one of the main rattles I was hearing.

Tightened an upper control link that I had not fully torqued.

Driver's side window - the rubber/felt window channel was knackered and even missing in some spots allowing the glass to bang around in the channel. Amazingly, all the rubber window seals are still available to buy, so I swapped out the driver's side pieces. The passenger side isn't nearly as bad, and the door panel is currently installed, so I will tackle that one later.

Today's focus was getting airflow over the Intercooler. On the 2nd Gen TII cars, there is a big rubber "accordion" gasket bolted to the hood that seals the IC to the hood under the hood scoop. I have  the gasket, just needed a way to attach it to my 1st gen hood.

The gasket:

The hole it needs to cover:

Built a frame out of 1/2" square tube using the gasket frame as a template, I think half inch will give the right amount of compression on the gasket:

The fit between pieces was actually pretty bad. Had a hard time getting square cuts that were 22.5 degrees. I worked the pieces to tighten up each joint

a bit after this photo was taken:

Then welded her up:

Then welded in bolts as studs to mount the gasket. Need to do a bit more welding tomorrow to close up the sidewall around a couple of the studs, then paint. I get the special panel bonding foam delivered tomorrow to attach it to the hood.

Writing this up with a few pictures, seems like such a simple part. But man I spent a lot of time getting those stupid little corner cuts to the dimensions I needed.This took me way longer than I thought it would - my fab skills are weak, lol.

My dad was huge into rotary Mazdas.  I can remember having 3+ RX-2s and -3s while living in an apartment even.  He had an RX-7 as soon as they arrived in '79.  This thread brings back memories.  Thank you for sharing!  Dad had one of the 1st turbo IIs in the US too.  He flew to CA to take delivery right off the ship.

Wish I had noticed this from the beginning.  A good friend of mine took a similar path.  First gen RX-7 in high school/college that he eventually brought to lots of track events.  Then he bought a crashed TII and swapped in the motor around '99 or so.  He actually made money on the deal, which lead to a steady secondary income selling RX7 parts on various mailing lists.  All the local junkyards knew him.  

He still has it, though it hasn't been down off the lift in years as far as we can tell (we often give him a hard time about it, as friends do :) ).

In reply to mfennell :

Yeah, I realize I'm about 15-20 years behind the trend on this one, though I did actually buy the motor 15 yrs ago, just now got around to stuffing it in 

A few pics of the intercooler frame installed. Also painted the hood satin black to match the newly affixed hood scoop.

To attach the frame, I used some extra special 3M goop suitable for "anti flutter" that is supposed to stay flexible and not shrink so it does not dimple the hood skin - not that that would matter much, this hood came off a decommissioned racecar... it's uh...been through some things.

Very carefully selected weights used during the curing process, lol.

being painted:

Gasket in place

It's probably too small for airflow, but I really like how this scoop looks

A quick pic next to the racecar before loading up to head out for the Deals Gap Rotary Rally

I wish I could say I planned this, but a cool little detail. The graphic on the intercooler peeks out from under the hood scoop

Overall, I'm calling the Deals Gap rotary rally a success. 

I had hoped to get a new tune loaded that would allow a little more fun, but my tuner saw some issues with fuel pressure, so I'm still in boost jail and had to just cruise around at light throttle and not much boost. Still a good time and the car didn't miss a beat.

Weather was great, met a couple of GRM'ers - and a bunch of other rotorheads. There was one other T2 swapped FB there, but I never found the owner.

A couple of pics from Fontana Dam area:

And a rotary BERKELY! Really nicely done. 

Quick update on my trusty (and a little crusty) rx7.

I drive the car pretty regularly for errands and such - and it really hasn't missed a beat. I do have a decent list of things I need/want to sort out over the winter.

I also need to do a bunch of interior work, which I am hoping to get started on in Dec or January.

I still don't have the car fully tuned so no full throttle and limited to 4-5 lbs of boost. Between other distractions and my tuner being pretty flaky on schedule, progress has been slow. I was actually scheduled to do a dyno tuning session tomorrow at a local shop, but my tuner flaked and we had to reschedule for next week. Aggravating, and that's after getting the special spark plugs he wanted me to use overnighted from Japan (well ok, actually just next day aired from Nevada, but still ).

I did take the opportunity over the weekend to put it on the scales and was pleasantly surprised. I was expecting it to be at least 100 lbs heavier. Once the rest of the interior is in and the AC added, I still should be well under 2500 lbs.

That hood scoop looks really clean.

The intercooler gasket frame is a neat solution. I may end up asking you for the dimensions, since finding a Turbo II hood near me is proving challenging. I really don't want to cut my NA hood, but I may end up taking that route eventually.

WondrousBread said:

That hood scoop looks really clean.

 

The intercooler gasket frame is a neat solution. I may end up asking you for the dimensions, since finding a Turbo II hood near me is proving challenging. I really don't want to cut my NA hood, but I may end up taking that route eventually.

I like the look of it a lot, but the opening is much smaller than a stock TII scoop. This was intended as a temporary measure. I have the composite bezel from a TII hood scoop, and I intend to modify the hood to essentially have a TII hood scoop that accepts that bezel. Easiest way is to cut the enitre scoop and mounting structure for the bezel out of a TII hood and graft into the FB hood, but I haven't really found anything local and shipping is expensive, plus steel TII hoods are pretty rare compared to AL ones.

I can share any info you like on the support frame. I made it to mate up to the stock TII accordian gasket, but If I were you, I'd plan to bite the bullet and purchase a TII hood. Unless you want a significant fabrication project.

BTW, I saved the original hood and cut up a spare one because I might eventually go with a front mount intercooler since the stock top mount is a limiting factor as you increase boost. That would have been plan A except I'd rather not relo my battery and I definitely need to retain A/C in the sunny south, which are both difficult with a FMIC.

sevenracer said:

I like the look of it a lot, but the opening is much smaller than a stock TII scoop. This was intended as a temporary measure. I have the composite bezel from a TII hood scoop, and I intend to modify the hood to essentially have a TII hood scoop that accepts that bezel. Easiest way is to cut the enitre scoop and mounting structure for the bezel out of a TII hood and graft into the FB hood, but I haven't really found anything local and shipping is expensive, plus steel TII hoods are pretty rare compared to AL ones.

 There used to be fiberglass TII scoop replicas available online (including both the scoop and the molded line that runs into the hood). I can try to find the website for you, but last I saw it was pretty out-of-date. Not sure if the owner still maintains it or offers the product anymore.

I can share any info you like on the support frame. I made it to mate up to the stock TII accordian gasket, but If I were you, I'd plan to bite the bullet and purchase a TII hood. Unless you want a significant fabrication project.

I've been planning to buy a TII hood for awhile, just can't actually get my hands on one. I know one guy who has a couple but isn't selling since he wants the spares (understandable).

I messaged a local-ish guy on IG who bought a parts car, asking if he needed the hood. Turns out he bought the entire car JUST for the TII hood.

Then there's one guy 5 minutes away from me who has one, but he isn't selling until at least the spring because he needs to test his car on the track to see if his turbo melts his current fiberglass hood. And after seeing the size of his turbo, I believe it actually might melt the hood.

 BTW, I saved the original hood and cut up a spare one because I might eventually go with a front mount intercooler since the stock top mount is a limiting factor as you increase boost. That would have been plan A except I'd rather not relo my battery and I definitely need to retain A/C in the sunny south, which are both difficult with a FMIC.

That's why I want the top-mount. I don't like cutting holes in the car to run the pipes, and it's a compromise as far as cooling.

The other option is a V-mount, but then I have all that fabrication to relocate the rad, the battery, mount the IC, lose the stock intake, add ducting, etc. You might not be able to run the stock AC lines and condenser location. And to do it without a hood-vent (which I really don't want) you need to get really clever to get all that heat out.

The IC & hood situation has turned out to be the most challenging part of the whole swap.

EDIT: The page looks different, so maybe it has been updated recently: https://www.blacktiemotors.net/product/fc-rx7-tii-style-hood-scoop-vent

It would still need quite a bit of work to blend it to the hood though.

Those pannasports, what size are they?  It looks like they're staggered but i could just be the picture. 

In reply to 79rex :

They're all 15X7's, but 2 different "model years". The fronts have a smooth painted finish and more modern center caps, and the rears have a grain in the casting. The rears also have a wider lip, which makes it look like a staggered setup - not sure if that's just styling or a different offset.

Funny story - when I met the guy to buy 4 used Panasports wheels years ago, he shows up with 6 wheels. He had bought 4 of the older style wheels from someone, but 2 of the wheels had been damaged with the centers completely broken out of the hoops. Someone had welded them back together - each spoke had a big, fat aluminum weld bead where they fractured! He bought them anyway, but chickened out on using them - and bought the 2 new ones. He offered the 2 extra wheels to me, and I took them but eventually tossed them.

Great thread man i just found it. Glad you got her back on the road. Only took a whole year! Makes me excited for my own car. 

sevenracer said:

A few pics of the intercooler frame installed. Also painted the hood satin black to match the newly affixed hood scoop.

To attach the frame, I used some extra special 3M goop suitable for "anti flutter" that is supposed to stay flexible and not shrink so it does not dimple the hood skin - not that that would matter much, this hood came off a decommissioned racecar... it's uh...been through some things.

Very carefully selected weights used during the curing process, lol.

being painted:

Gasket in place

It's probably too small for airflow, but I really like how this scoop looks

A quick pic next to the racecar before loading up to head out for the Deals Gap Rotary Rally

I wish I could say I planned this, but a cool little detail. The graphic on the intercooler peeks out from under the hood scoop

On the #53 race car. Are you running the stock + 13" wheels. If so what size tire are you running?

In reply to chiquito1228 :

I store the car on stock wheels/junk tires. I race with 205 60 13's on 13X7 wheels. I think some people used to run 224 45 13 Hoosiers in my class before we went to a spec Toyo tire, but I don't know how they made them fit. I get some tire rub with 205's if I set the rear too low.

I have raced with 205 60 13 Toyo RA1's on stock 13X5.5 rims, and it works but is not optimal.

This Thanksgiving, I'd just like to say I'm thankful for boooooost. 

Dyno day yesterday went pretty well - actually kind of too well. Going into this project, I wasn't looking for huge power. I would have been disappointed with less than 200whp, and was hoping for 220 or so. Actual number on the first pull...umm....275whp and about 260tq. At 8psi. This I was not expecting.

I say it went a little too well, because my fuel pump is not keeping up - fuel pressure is falling off at upper rpm. And all of this is just on the stock wastegate spring, no boost control.

Also, the stock intercooler seems to be insufficent, at least stationary on a dyno.

So the dyno session ended very early with the following takeaways:

1. Redline set at 5900 for now to keep the motor safe.

2. Need to upgrade the pump and add an aftermarket fuel pressure regulator. Tuner guy seemed very certain I am running out of fuel pump. I have a Summit copy of a Walbro 255 which should easily support these power levels, so I am suspicious of the stock FPR. But I'm a newb in all this, so what do I know. I guess it doesn't really matter because the current pump is annoyingly loud and on my list of things to change. I am researching if it is viable to add the FPR in series after the the stock FPR. Otherwise, I need a different fuel rail.

3. Need to decide if I pursue a front mount intercooler - I am dreading opening this can of worms because lots of fab required, and the battery likely has to move, and AC becomes much harder.

4. I probably need to start sourcing a taller rear gear. 1st and 2nd gears are used up pretty quick.

Is that on the stock turbocharger?

That number seems really high. Most people say the stock turbo runs out of steam at around 250 wheel, depending on a number of factors. And that's at like 14psi.

275 wheel puts you at at least 300 crank, which is a lot from the stock turbo. Stranger things have happened though :)

300 crank is about 220-230 at the wheels depending on dyno.  Drivetrain losses are on the order of 30%.

WondrousBread said:

Is that on the stock turbocharger?

That number seems really high. Most people say the stock turbo runs out of steam at around 250 wheel, depending on a number of factors. And that's at like 14psi.

275 wheel puts you at at least 300 crank, which is a lot from the stock turbo. Stranger things have happened though :)

Stock turbo as far as I can tell. The motor was a jdm import I purchased about 15 yrs ago. Everything looked stock.

I agree is seems way higher than expected. I guess the simplest explanation would be the dyno was measuring high. I guess another possibility is the MAP was reading low? The intake and exhaust are significantly less restricted than stock.

I did question the tuner about how high it was, and he just asked if I was sure it was a stock turbo. This was all on a Mustang dyno.

The actual number isn't really that important. I mainly want good reliability and drivability. And it's pretty good on that front at this point.

In reply to sevenracer :

I knew a guy who had purchased several JDM import engines, and he said he rarely found one that was 100% stock. He said lots of them in Japan had been modified with hybrid turbines, clipped exhaust wheels, etc. Not sure how common it really is, but it's certainly possible yours isn't stock.

At the end of the day you're happy with it, which is what matters

In reply to sevenracer :

Thank you so hard to find 4x110. I was just thinking of running the oem wheels