13b swap?
 

ok, so im down a rotor on my 12a, and im thinking its actually going to be cheaper to put in a 13b for now (until i can rebuild my 12a). as bad as this may sound, there is an '84 gls-se with a good LOOKING 13b that i can get my hands on really cheap. im sure i can get the wiring harness and fuel pump off it, what all else would i need? do the motor mounts change?

and at some point, i want to go back to the 12a with a turbo setup, so anything i do id like to keep reversible... can i just put the 13b in there and use the 12a ignition system? will it work the same?

My 2 cents. First off, the 12a may not be re-buildable. You won't know until you get it all apart. Housings for 12a's are getting very dear. Do that first, see what you've got, and go from there. It all is a matter of time and money. You can switch back to the 12a if you want, but that to me seems to be a lot of work to do twice. Changing the wiring back and forth doesn't sound easy to me, but hopefully someone who has done it can chime in and let you know what you are in for. Good luck with it.

if you want a 13B, get the 13B. if you want the 12A, then just work on getting a running 12A together. putting the 13B in with the intention of switching back to the 12A really makes no sense at the end of the day. everything you do with a 13B installation (depending on possible welding for the exhaust) is reversible.

i know it doesnt make much sense to do it twice, but the setup i want for the 12a is gna take a while to get together, i figured 13b for now, and once i get my ideal 12a together i would swap it back in. i gotta have my rotary!!! like a week ago!

The easiest route would be to just buy another 12a shortblock to swap with yours. Then you can pull apart the original and see what can be salvaged and decide what kind of build you want to do while still having a car to drive.

Swapping in a 13b is quite a project in itself. The tank is different, the fuel system will need to be upgraded to handle EFI, and then you've got the electronic mess to deal with. It's probably easier to drop in the 13b and do a carb setup, but that's still an expensive and time-consuming option.

I got a 12a that ran fine I'd sell you. Got a few videos of it starting and running right before I pulled it.

I've done the swap to 13B and, as much as I enjoyed the challenge, it wasn't easy or cheap. Swapping the harness requires pulling the dash - loads of fun. Don't forget you'll need a new exhaust header since the 13B is longer and the bolts don't match up to the 12A system. I bought the RB 12A-13B motor mount conversion bracket from Racing Beat but some guys who are handier than me have "converted" the 12A mount by drilling some longer holes. I wanted it to look good so I opted for the shiny RB bracket. I think my biggest problem was the fuel system. For that I swapped the fuel tank, purchased new pumps & filter and installed a new (larger) send line (purchased from a forum member who had a SE parts car). Maybe you have access to a shop with proper tools and equipment, but for me the DIYer, doing all that work to convert to a 13B and THEN switching it back to 12A in the future seems a bit crazy. Good luck on whatever you decide.

12a irons, -se rotating assy/housings, slotted motor mount, 13b header, rx4 intake manifold, 12a ignition, 12a nikki... enjoy your newfound torque.


Isaac

My dream motor.

ok, not to sound dumb, but what is so "special" about that setup? like how does it give more torque/power?

I took the 13b manifold welded outlet 2 holes. Redrilled and tapped 10 x 1.25mm holes. Voila 12a exhaust bolts up just fine :) took about 15 minutes.

Love pulling dashes :) lol I work at Toyota and I pulled a lot of instrument panels for some really silly stuff on sienna mini vans.

funnily enough this is the exact setup i have on my car... i wasnt aware that i possessed anyone's "dream motor" haha

it's not the "doing it twice" that makes no sense to me, it's the part where you want a 12A, but you're going to install a 13B to get there. the fact that you're asking all of this says to me that you will have to acquire the 13B and whatever else you will need to install it (it can be simple or complicated. that's really just a product of how you want to run it.) and the time, effort and money that it will take to get that together, I can't imagine it's not just easier waiting to get a 12A and then moving from there to your ultimate goal.

my guess: compared to a stock 12A, the increased displacement and inherent better velocity (possibly AFRs, too) will yield better torque. remember the displacement is increased on the same ports.

yeah i think im just going to rebuild the 12a.. i gotta take it apart first lol