Hey guys! So, I'm starting on the journey of restoring a 79 Rx7. I actually started with an 84 GS, low mile, automatic, interesting white checkered fabric interior. Once I discovered the extent of the rust damage to my 84, went back and forth on fabricating the framerails, then found a 79 shell without rust which I am retrieving at the end of the week.

Now, I know not everything from my 84 will swap to the 79. I need to swap:

Lights
Glass
Interior
Dash
Bumpers
Drivetrain
Sunroof(both are original sunroof cars)

What problems will I run into swapping these parts? I've been told the taillights won't swap but the glass will. I'm sure there are other issues I will run into. I don't plan on swapping any of the stereo equipment anyway, I'm aware those Clarion amplifiers behind the seats are some weird little things.

Thanks guys. I appreciate the help.

 

All will fit but to fit tail lights you will need to fit the rear panel off the 84

 

All will fit? You have NO IDEA how relieved I am Thank you.

Is fitting the rear panel just a matter of drilling holes to run the studs through? I haven't dug into the taillight assembly on the 84 yet.

 

The tail lights are longer and different shape on the 84 and u need to cut of the rear panel and fit to the 79 rx7

 

How much wiring harness hacking should I plan on? Am I looking at more or less plug and play on the motor? How about the dash? The 79 still has an intact wiring harness.

 

Keep all the wiring 79 except the distributor.
Use the 79 intake and carb.
Use the 84 exhaust.
Use the 79 trans.
Use the 84 engine with flywheel
Use the 79 dash - don't mess with the 1984 dash - it will fit but doing all the wiring to make it work isn't worth it.
Use the 84 front spindles and brakes
Use the 84 rear end if it has disc. (and drive shaft)

 

That's where it gets tricky. The 79 is gutted save for rear end, dash, and wiring harness and the dash looks rough from the pics. I was planning on aftermarket carb and exhaust, so that takes that off the list. I'm not sure what I'm looking at with the ECU and that rats nest of wires near the carb. Also unsure on ignition. I'm beginning to see why the 79 dash is necessary. Is there a way to make the 84 auto trans play nice with the 79 shell or am I out of luck there?

 

The auto will fit ok bur may need to modify the rear mount and I would swap the complete 84 wiring loom and dash assy in to the 79 body

 

Ok guys, here's where I'm at.

I'm getting most of the dash with the 79. Using the 79 wiring harness. Swapping seats carpet and door panels out of the 84. Engine out of the 84 with aftermarket carb and exhaust. I'm buying a transmission and drive shaft out of a manual 79 on the other side of the state. I'm using the 79 rear end. I'm using the windshield and rear glass out of the 84. I'm using the bumpers off the 84(do I need fenders with that?). I'll need to source a manual flywheel, clutch assy, and counterweight for the 84 engine. I'll need to source a set of tails, and moonroof glass from a 79. Have I missed anything? Thanks for the help guys.

. .

 

If you use the 84 bumper, you will want the fenders also. You might as well get the rear bumper from the 84 so it matches the front.

No counter weight needed. The manual trans does not have one.

 

I got my 79 home last night. Long drive with a trailer, almost dropped it off the edge in Chicago over a violent section of road. Also bought a 79 manual trans.

I'm hoping to swap both bumpers, both doors, and the front fenders from the 84. Will the doors bolt up too? Seems easier than trying to fix the issues with the ones on the car.

I'm also concerned that I'm missing a lot of dash trim. Could someone please link me to a clear picture of a 79 dash? What is the cross reference for use in the 79 dash? Is it 79 only, or 79-80?

 

The doors are a direct bolt on. If the 84 has power windows, you'll need to wire that yourself. The 79/80 did not have power windows.

As for the dash, the 79-83 used the same dash cap. The 84/85 dash parts are not compatible with 79-83.

 

Thanks. Do you know if the bezel in the center of the dash 79-83 is the same too? How about glovebox?

I fit up the 84 doors to the 79 today. Are the power mirrors plug and play or do I need to do some splicing? The doors I got on the 79 did not have mirrors on them. I notice some wires going places I didn't expect in a door that only has power mirrors(84, manual locks and crank windows). Can anyone enlighten me on what's going on with the extra wires in the 84 door? The driver side has an extra harness but the passenger side does not. Are the 4 pin power mirror harnesses the same as the 79? Or am I all sorts of backwards?

 

I THINK the center bezel will work 79-83 but I'm not 100%. I do know there are differences with the competent configuration.

Power mirrors on a 1979/1980 are rare. Best to use the 84/85 switch and find a place to mount it.

1984/85 door electronics can contain power mirrors/windows/lock illumination. Yours may or may not have the mirrors or illumination. No first gen had power locks. The door probably has the wires to accommodate the features I listed but my not have them installed.

I think it's time you dug in to the wiring for the 79 and 84 to compare the two where you have questions. We would have to do the same digging and it might as well be you.

Foxed.ca - Mazda RX-7 Manuals

 

I was going to ask about manuals. Thanks.

Might be simpler to run manual mirrors, never got the power mirrors troubleshot on the 84. Looks to be a lot of non power mirrors around eBay for not much $.

I'm sure I'll be back here before long. Thanks for your help so far.

 

I got one more question for y'all. I got a new 79 manual starter and a 79 manual trans. Motor is an 84 12a. What fly wheels can I use?

 

You will need a 79 flywheel

 

The shaft on the motor will fit in a 79 flywheel?




This is a manual flywheel, right?

 

You will want to used a flywheel that matches the front counter weight. In your case a 83-85 flywheel. Using the wrong flywheel can cause vibrations in the engine.you can also just leave the rear auto counter weight that is on there and install a aftermarket flywheel that will Bolt on you will also need to install a pilot bearing and seal.

 

Would it be a bad idea to use a 79 counterweight and fly wheel?

 

I would advise against it. I'm not big on mixing and matching parts of the rotating assembly. You can mix 79-80 f/r counterweights with 81-82 rotors and vise versa. But the 83-85 rotors are much lighter. It's not what the were design to balance.

 

So is there a way I could run my 79 manual trans, 79 manual or 84 auto starter, aftermarket fly wheel and 84 engine with auto counter weights?

 

I hate to beat a dead horse, but I wanna be sure I know I've got this right.

Could I run

84 engine

84 front and rear counterweight from automatic setup

Racing Beat 74-82 Lightweight Steel Flywheel

Racing Beat Clutch and Pressure plate

1979 12a starter


And do that without causing damage to the rotating assembly?

 

Yes if you have a 84 engine with 84 front and rear auto counterweights you can run a 74-82 lightweight flywheel with a 79 12a manual starter but you will need the appropriate clutch 74-82 . Don't forget to add a pilot bearing. You can also used a 83-85 light weight flywheel no problem the difference is the pressure plates and disk diameter. If you haven't already ordered a flywheel I would use a 83-85 . If your set in using a 74-82 flywheel I have a new aluminum one that's been sitting in a box for about 10 years That I can sell you for half of what racing beat charges. But it's missing the hardware.