anjhindul

My 12a GSL recently died I put 1200 into trying to resurrect her but the rear rotor will not hold compression after 3 complete rebuilds including replacing the rotors and retooled atkins housings OH WELL. I want to do a 13b conversion with fuel injection now. I know I will need

exhaust,
fuel pump,
and I believe I need to get a gsl-se front cover and oilpan.
I have the 13b block with water pump alternator etc.

Am I missing anything? I heard the FC 13b will bolt right on to the old FB trany, is this true? Do I need to do anything with the clutch? I seem to remember reading SOMETHING about this but can't remember or find it after 2 hours of using search!!

Thanks in advance for all advice

doogy2

iTrader: (2)

Well u can take your front cover and oil pickup off your 12a if u have a good vice and a big hammer u can just use the 12a mount and straighten it out

GySgtFrank

iTrader: (4)

OK, you asked for it, so here goes with my opinion.

There are lots of ways to do this swap and people have come up with a lot of different solutions. Firstly, just how much effort are you willing to put into your project before you ever see it run again? The EFI portion is not a straightforward swap, as you need to upgrade pretty much every supporting system to make it work. Unless you REALLY want or need the EFI, then staying carbureted will be far easier and probably cheaper to do.

You have the basics to get the 13B in there, the GSL SE oil pan and front cover. You can use a 12A front cover, but the oil metering pump is different than the 13B pump. If you're deleting the OMP and premixing, this is not a problem. If you want the working OMP then the 13B GSL SE cover is required. The easiest route on the engine mount, unless you're a glutton for measuring and fabrication, is to get the Racing Beat 13B front mount. It places the engine in the chassis at the correct position and height.

The naturally aspirated (NA) 13B will bolt up to your earlier transmission fine and there should be no problems with the clutch as long as you use the flywheel (or equivalent counterweight) for the engine you plan to use. The TII engines used a larger flywheel and different transmission so they do not bolt up to the earlier transmissions while using the TII flywheel. The slave cylinders are also slightly different between the TII and naturally aspirated cars.

If you have to have the EFI, a stand alone ECU and supporting fuel system (pretty much everything including replacement or major modifications to the fuel tank) will be the easiest route. Note that easiest is a relative term here. Ignition upgrades are also highly recommended. You can swap in the entire stock 13B EFI, fuel, and ignition systems, but it requires a lot of modifications from one end of the car to the other (ask me how I know ) Exhaust is pretty straightforward if you use the Racing Beat or equivalent header. If your engine is a NA S4 you can use the header with the secondary actuator tube to operate your secondaries. The S5 will require you to use the air pump or some equivalent system to operate the secondaries. The FB driveshaft should not be a problem if you stay with your transmission or a NA FC transmission. Using a TII transmission will require a TII flywheel (or counterweight), TII slave cylinder, and incur it's own set of modifications. The FB driveshaft will not fit. From what others have said the FB cooling system is adequate for a NA 13B. I went with the FC system but I guess it's not absolutely necessary.

Not trying to rain on your parade, but letting you know to carefully plan out what you want and can accomplish, as well as how you're going to do it, BEFORE you start the tear down. This project can get overwhelming quickly if not taken in preplanned stages. Most importantly keep it fun by not needing to have it done on a certain schedule. As usual it will cost more and take FAR longer than you might want to believe.

Have fun with your project.

anjhindul

Well Thank you GySgyFrank! most interesting read. I was planning on an early 13b and I wanted the mechanical fuel injection instead of the EFI just to simplify the swap. I was planning on one of the older 13b's the first 1985 FI ones I heard they are mechanically injected.

I am glad I asked on here before I actually started this project... looks like I want a new car that RUNS before I start! haha this could take an entire year... or four!

I have always premixed my fuel. A little extra oil isn't ever going to hurt a rotary engine.

doogy2

iTrader: (2)

I think you are confused the mechanical and electronic is the omp all of them are electrical fuel injected

82transam

iTrader: (18)

No Rotary ever had a mechanical fuel injection system, like doogy said, they are all EFI....

turbogslse

iTrader: (3)

I know you're thinking the 13B route, but it makes me wonder why after 3 rebuilds the motor won't hold compression. It sounds like something was amiss on the rebuild. Have you done many rebuilds before, or was this your first? If your first, did you have someone who was experienced go over the parts with you that you're rebuilding with? Just saying from my own experience, that parts which looked fine to me were junk after I learned more about what works and what doesn't from my experienced builder. Just trying to be helpful here, because in the end it might be far easier to tear down the 12A, port it, fix the compression issue and be on your way. Not that going the "long way" via a 13B swap wouldn't be fun or worthwhile, I'm not one to talk.

doogy2

iTrader: (2)

Just by a intake and card for the 13b and be done

doogy2

iTrader: (2)

I ment carb

doogy2

iTrader: (2)

A good webber will get you nice power with a header

anjhindul

Thank you for your input I replaced ALL seals. all oil, water jacket, APEX springs/corner/side seals, OIL control rings/seals I replaced the rotors and the housings with retooled from Atkins. the only part of the engine (block) that didn't get replaced was the irons, front cover, OPP. I did not machine the irons but I would be very surprised if they needed it to the point I would get compression around 5-15psi in 2/3 strokes and one of 40-60psi even after how horrible the engine died. plus the inconsistent stroke pressure doesn't point to the irons but to an APEX.

Yes this was my first second and third rebuild lol!

turbogslse

iTrader: (3)

Yep, plenty that can be done on a 12A or 13B with aftermarket carb. I think of the project this way:

1. Fix the 12A and get it running - least resistance (although may be frustrating 4th time around, I get that)
2. Find a good running GSL-SE motor & wiring harness and swap that in. You don't mention the year, but if your GSL is a 84 or 85, then you're probably going to have an easier time of it than if it were an 83 or 82 GSL. It's a project for sure, could be done in a weekend with a full donor car. But then, if you have a full donor GSL-SE....
3. You'd probably want a 4 port 13B to use one of the aftermarket carbs. There are older 4 port 13B's from pre-RX-7s, not sure the quantity/quality of those. Might be a hunt if you don't have a good lead or supplier.

Anyhow, some food for thought.
Dave

turbogslse

iTrader: (3)

Interesting. Sounds like you did all the right stuff. Esp if you got the rotors from atkins, and used new apex seals. The only thing left would be some seat time. I know that my son's motor had some initial starting issues because we used used housings with new seals, and the seals were bypassing gasses in the housing - but I doubt that he's down to 15psi, probably more like 80. Gradually it's getting better.

Anyhow, after thinking about all this advice, what direction are you leaning?

doogy2

iTrader: (2)

In my race car I just did a 6port dime a doesn't and put a set of Webber's and a header works good and really simple used the 12a dizzy and Hooke the fuel lines up and remove all the emission stuff and a buch more power then stock. Just an option

anjhindul

well the 12a usually runs around 65-80 and I can get her started with a cup of oil but then she A smokes out the neighborhood and B has no power I tried to seat her before and went about 1500miles with no change in the compression is it possible for the irons to cause this kind of a problem for 2/3 of the cycles?

anjhindul

Turbogslse, I just found a running 1985 13b for 1000! sweet! owner says it has a flooding problem when left sitting... all I need to do is install my normal fuel cutoff switch/security switch I am thinking of grabbing it ASAP and doing my first custom EFI setup. anyone have any advice on stock setup (I don't really want 450 HP! haha) customization of EFI? what controller to use, all suggestions or even presetups if anyone has them for a stock 85 13b

Sh00bs

iTrader: (8)

whats going on! just stumbled upon this thread as i've begun my process in pulling my 12a to 13b swap as well! i have a 13b from '85 that's sitting at a friends house in WV (im in MD) im going to grab in another week or so. my nikki was giving me trouble after i replaced the O rings and gasket due to a coolant leak and then while carb was off stipped it but vaccuum hoses are messing me up and planning to turbo down the road so would rather go with efi.
anyway here's what i have so far:
hood removed, intake off, cables off, gas lines off, wiring harness off and labeled, exhuast unbolted and driveshaft unbolted. just drain the coolant and a few more hoses then engine mounts and she should be free!
with an '85 13b, engine mount adapters will still be needed, yes? I'm going to manassas this weekend for a meet and grabbing a LSD as well to install while the tranny is out. Planning to turbo as well down the road after i get the swap done and everything working correctly. Since i'll be going boost later, should i just upgrade my flywheel now to save me from the PITA later and it would just be overkill with the n/a engine for the time being.
can someone recommend a good fuel pump to upgrade to?

Best of luck with your swap! hopefully we would could help each other through the process