Contemplating starting my rx-3 project. I've been doing some research, articles and threads here on the rx-7 club forum. I have a good amount of experience working on cars but almost none on rotaries. I have a 1973 rx-3 purchased a few years ago. It had a TII in it at one time. No motor now. TII trans still in place. I have a S5 TII engine that I would like to swap in. I think that the previous owner of the car had the TII motor mounted in the car by using a front cover off of an older car. So for mounting the engine I am considering 3 options.
1) GSL SE front cover. Looking at the S5 motor appears that the turbo oil drain back is in the front cover. Also S5 utilizes a electronic OMP. So these issues would have to be overcome. Any suggestions would be appreciated.
2)Modifying the S5 front cover, welding bosses to bolt the motor mount.
3)Making a custom cross member to P/U S5/S4 FC mounts, I did own a rx3 project that was set up this way, although I never saw an engine in it. Looking at it might not be enough room to clear steering linkage.
I have read differing accounts of what oil pan would work. Someone at one of local rotary shops told me that I need a old school 13b oil pan or an aftermarket. Also GSLSE? So far the rest of my plan as it is. Use stock S5 wiring harness and ECU eliminating unused circuits. Modify stock gas tank to accept the S5 fuel pump and sender. Any helpful info would be appreciated.

 

Gsl-se front cover and oil pan is your best bet.you will have to modify the front cover for the turbo oil return line.if I were you I would run s4 stock Ecu instead of the s5,I hate the s5 just because it needs the electric omp hooked up or else it will go into limp mode and won't run.

You can use s5 Ecu but will need electric omp hooked up to the harness and tucked away somewhere on the car just so the Ecu is happy(only if you use gsl-se front cover).

What I do normally if running s5 motor is put gsl-se front cover and oil pan
Run all s4 electronics ,injectors,throttle body with TPS,water thermo sensor,afm,etc.
I get a s4 rx7 chassis harness and modify it to power up the Ecu,leading and trailing coils,and crank angle sensor.

I guess I'm just used to running the s4 turbo Ecu and works well for me,my 12a is running all s4 turbo components with hybrid stock turbo at 10 pounds off boost with no problems.

 

U can use either 12A or 13B GSLSE front cover. U are going to need a GSLSE oil pan and turn it around plus drill new holes on it.. also u are going to have to extend the oil pick tube..

 

^only on a rx2.
Rx3 has sump in front so the gsl-se pan and oil pick up is perfect for it.

 

Any pictures of the car?
A rx3 is on my to buy list,but first I'm trying to hunt down a 67 fastback mustang lol.

 

Ok, I'll try to get some pics up soon.

 

I do have a 66 fastback.

 

I owned a 68 fastback about 8 years ago but sold it and boy do I regret it now.im searching now for 67 or 68 fastback but prefer the 67.

Is this the same rx3 you were selling not so long ago?

 

I agree 67 cleaner look, no side marker lights, although sidemarkers are a good safety feature. No, I did sell that one. This is another one that I've had for awhile.

 

Here are a few pics,

 

very nice project

 

looks good... very nice starting point

 

Very nice find, car appears to be straight.

 

GSL-SE front cover and oil pan. have someone weld a bung on it for oil return. or drill and tap and use thread sealant.

s5 motors have the good rear iron, i have an s4 in my rx3. i went standalone on my rx3 so no reccomendatins on ecus from me.


got any pics of the trans tunnel? did they hack it up for the TII trans?

you have a good jump on the swap thats for sure.

 

Ok, thanks everyone for the positive comments. I'll go with recommendations gslse front cover/oil pan.

 

12-a front cover will do fine. gsl-se front cover is just a forum hype lol

 

nice 3...you guys out west are so blessed

 

Very nice RX-3, gunna keep an eye on this one. One day, I will have a turbo'd 3, one day.

Sent using RX7Club for Android.

 

I've been doing some work on the old mazda recently. My goal for now is just to get it running. Maybe kinda "rat rod" style. Mechanically sound but cosmetically as it is.

 

I going to try to chronicle the build on here. This is my first Mazda project. Pulled from my TII. Ive got a gsl se front cover and oil pan. I was thinking about this universal no weld for the turbo oil return.
Also the omp can I adapt a s4 or gsl se omp? I know that I have to keep the s5 omp wired into the harness.

 

I'm thinking brakes, stock for now. I made this because I did not have anyone around to help me bleed. It works. The booster holds vacuum. Callipers are stuck. Brake disks are not available but they look ok. I think i'll just bead blast the rust off and run em. I think I'll run a gsl se master( cause I have one already), after market adjustable proportioning valve. I'm also thinking that might get braided steel brake lines made up.

 

For omp run the gsl-se with the cover that way you can use any s4 or s5 turbo omp lines without any mod.if you run the s5 ecu and harness just hav the omp plugged in and tucked away where it won't get in the way.

 

Cool, thanks for the info. I've been looking at your build threads for ideas. How do you do your turbo oil return lines? Drill and tap timing cover for AN/NPT adapter?

 

You can drill and tap or what I do is weld the AN fitting on the front cover so there will be no leaks.

 

Dave, thanks for the advice/ info.